evtexture

basicsr/metrics/psnr_ssim.py

+import cv2
+import numpy as np
+import torch
+import torch.nn.functional as F
+
+from basicsr.metrics.metric_util import reorder_image, to_y_channel
+from basicsr.utils.color_util import rgb2ycbcr_pt
+from basicsr.utils.registry import METRIC_REGISTRY
+
+
+@METRIC_REGISTRY.register()
+def calculate_psnr(img, img2, crop_border, input_order='HWC', test_y_channel=False, **kwargs):
+    """Calculate PSNR (Peak Signal-to-Noise Ratio).
+
+    Reference: https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio
+
+    Args:
+        img (ndarray): Images with range [0, 255].
+        img2 (ndarray): Images with range [0, 255].
+        crop_border (int): Cropped pixels in each edge of an image. These pixels are not involved in the calculation.
+        input_order (str): Whether the input order is 'HWC' or 'CHW'. Default: 'HWC'.
+        test_y_channel (bool): Test on Y channel of YCbCr. Default: False.
+
+    Returns:
+        float: PSNR result.
+    """
+
+    assert img.shape == img2.shape, (f'Image shapes are different: {img.shape}, {img2.shape}.')
+    if input_order not in ['HWC', 'CHW']:
+        raise ValueError(f'Wrong input_order {input_order}. Supported input_orders are "HWC" and "CHW"')
+    img = reorder_image(img, input_order=input_order)
+    img2 = reorder_image(img2, input_order=input_order)
+
+    if crop_border != 0:
+        img = img[crop_border:-crop_border, crop_border:-crop_border, ...]
+        img2 = img2[crop_border:-crop_border, crop_border:-crop_border, ...]
+
+    if test_y_channel:
+        img = to_y_channel(img)
+        img2 = to_y_channel(img2)
+
+    img = img.astype(np.float64)
+    img2 = img2.astype(np.float64)
+
+    mse = np.mean((img - img2)**2)
+    if mse == 0:
+        return float('inf')
+    return 10. * np.log10(255. * 255. / mse)
+
+
+@METRIC_REGISTRY.register()
+def calculate_psnr_pt(img, img2, crop_border, test_y_channel=False, **kwargs):
+    """Calculate PSNR (Peak Signal-to-Noise Ratio) (PyTorch version).
+
+    Reference: https://en.wikipedia.org/wiki/Peak_signal-to-noise_ratio
+
+    Args:
+        img (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+        img2 (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+        crop_border (int): Cropped pixels in each edge of an image. These pixels are not involved in the calculation.
+        test_y_channel (bool): Test on Y channel of YCbCr. Default: False.
+
+    Returns:
+        float: PSNR result.
+    """
+
+    assert img.shape == img2.shape, (f'Image shapes are different: {img.shape}, {img2.shape}.')
+
+    if crop_border != 0:
+        img = img[:, :, crop_border:-crop_border, crop_border:-crop_border]
+        img2 = img2[:, :, crop_border:-crop_border, crop_border:-crop_border]
+
+    if test_y_channel:
+        img = rgb2ycbcr_pt(img, y_only=True)
+        img2 = rgb2ycbcr_pt(img2, y_only=True)
+
+    img = img.to(torch.float64)
+    img2 = img2.to(torch.float64)
+
+    mse = torch.mean((img - img2)**2, dim=[1, 2, 3])
+    return 10. * torch.log10(1. / (mse + 1e-8))
+
+
+@METRIC_REGISTRY.register()
+def calculate_ssim(img, img2, crop_border, input_order='HWC', test_y_channel=False, **kwargs):
+    """Calculate SSIM (structural similarity).
+
+    ``Paper: Image quality assessment: From error visibility to structural similarity``
+
+    The results are the same as that of the official released MATLAB code in
+    https://ece.uwaterloo.ca/~z70wang/research/ssim/.
+
+    For three-channel images, SSIM is calculated for each channel and then
+    averaged.
+
+    Args:
+        img (ndarray): Images with range [0, 255].
+        img2 (ndarray): Images with range [0, 255].
+        crop_border (int): Cropped pixels in each edge of an image. These pixels are not involved in the calculation.
+        input_order (str): Whether the input order is 'HWC' or 'CHW'.
+            Default: 'HWC'.
+        test_y_channel (bool): Test on Y channel of YCbCr. Default: False.
+
+    Returns:
+        float: SSIM result.
+    """
+
+    assert img.shape == img2.shape, (f'Image shapes are different: {img.shape}, {img2.shape}.')
+    if input_order not in ['HWC', 'CHW']:
+        raise ValueError(f'Wrong input_order {input_order}. Supported input_orders are "HWC" and "CHW"')
+    img = reorder_image(img, input_order=input_order)
+    img2 = reorder_image(img2, input_order=input_order)
+
+    if crop_border != 0:
+        img = img[crop_border:-crop_border, crop_border:-crop_border, ...]
+        img2 = img2[crop_border:-crop_border, crop_border:-crop_border, ...]
+
+    if test_y_channel:
+        img = to_y_channel(img)
+        img2 = to_y_channel(img2)
+
+    img = img.astype(np.float64)
+    img2 = img2.astype(np.float64)
+
+    ssims = []
+    for i in range(img.shape[2]):
+        ssims.append(_ssim(img[..., i], img2[..., i]))
+    return np.array(ssims).mean()
+
+
+@METRIC_REGISTRY.register()
+def calculate_ssim_pt(img, img2, crop_border, test_y_channel=False, **kwargs):
+    """Calculate SSIM (structural similarity) (PyTorch version).
+
+    ``Paper: Image quality assessment: From error visibility to structural similarity``
+
+    The results are the same as that of the official released MATLAB code in
+    https://ece.uwaterloo.ca/~z70wang/research/ssim/.
+
+    For three-channel images, SSIM is calculated for each channel and then
+    averaged.
+
+    Args:
+        img (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+        img2 (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+        crop_border (int): Cropped pixels in each edge of an image. These pixels are not involved in the calculation.
+        test_y_channel (bool): Test on Y channel of YCbCr. Default: False.
+
+    Returns:
+        float: SSIM result.
+    """
+
+    assert img.shape == img2.shape, (f'Image shapes are different: {img.shape}, {img2.shape}.')
+
+    if crop_border != 0:
+        img = img[:, :, crop_border:-crop_border, crop_border:-crop_border]
+        img2 = img2[:, :, crop_border:-crop_border, crop_border:-crop_border]
+
+    if test_y_channel:
+        img = rgb2ycbcr_pt(img, y_only=True)
+        img2 = rgb2ycbcr_pt(img2, y_only=True)
+
+    img = img.to(torch.float64)
+    img2 = img2.to(torch.float64)
+
+    ssim = _ssim_pth(img * 255., img2 * 255.)
+    return ssim
+
+
+def _ssim(img, img2):
+    """Calculate SSIM (structural similarity) for one channel images.
+
+    It is called by func:`calculate_ssim`.
+
+    Args:
+        img (ndarray): Images with range [0, 255] with order 'HWC'.
+        img2 (ndarray): Images with range [0, 255] with order 'HWC'.
+
+    Returns:
+        float: SSIM result.
+    """
+
+    c1 = (0.01 * 255)**2
+    c2 = (0.03 * 255)**2
+    kernel = cv2.getGaussianKernel(11, 1.5)
+    window = np.outer(kernel, kernel.transpose())
+
+    mu1 = cv2.filter2D(img, -1, window)[5:-5, 5:-5]  # valid mode for window size 11
+    mu2 = cv2.filter2D(img2, -1, window)[5:-5, 5:-5]
+    mu1_sq = mu1**2
+    mu2_sq = mu2**2
+    mu1_mu2 = mu1 * mu2
+    sigma1_sq = cv2.filter2D(img**2, -1, window)[5:-5, 5:-5] - mu1_sq
+    sigma2_sq = cv2.filter2D(img2**2, -1, window)[5:-5, 5:-5] - mu2_sq
+    sigma12 = cv2.filter2D(img * img2, -1, window)[5:-5, 5:-5] - mu1_mu2
+
+    ssim_map = ((2 * mu1_mu2 + c1) * (2 * sigma12 + c2)) / ((mu1_sq + mu2_sq + c1) * (sigma1_sq + sigma2_sq + c2))
+    return ssim_map.mean()
+
+
+def _ssim_pth(img, img2):
+    """Calculate SSIM (structural similarity) (PyTorch version).
+
+    It is called by func:`calculate_ssim_pt`.
+
+    Args:
+        img (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+        img2 (Tensor): Images with range [0, 1], shape (n, 3/1, h, w).
+
+    Returns:
+        float: SSIM result.
+    """
+    c1 = (0.01 * 255)**2
+    c2 = (0.03 * 255)**2
+
+    kernel = cv2.getGaussianKernel(11, 1.5)
+    window = np.outer(kernel, kernel.transpose())
+    window = torch.from_numpy(window).view(1, 1, 11, 11).expand(img.size(1), 1, 11, 11).to(img.dtype).to(img.device)
+
+    mu1 = F.conv2d(img, window, stride=1, padding=0, groups=img.shape[1])  # valid mode
+    mu2 = F.conv2d(img2, window, stride=1, padding=0, groups=img2.shape[1])  # valid mode
+    mu1_sq = mu1.pow(2)
+    mu2_sq = mu2.pow(2)
+    mu1_mu2 = mu1 * mu2
+    sigma1_sq = F.conv2d(img * img, window, stride=1, padding=0, groups=img.shape[1]) - mu1_sq
+    sigma2_sq = F.conv2d(img2 * img2, window, stride=1, padding=0, groups=img.shape[1]) - mu2_sq
+    sigma12 = F.conv2d(img * img2, window, stride=1, padding=0, groups=img.shape[1]) - mu1_mu2
+
+    cs_map = (2 * sigma12 + c2) / (sigma1_sq + sigma2_sq + c2)
+    ssim_map = ((2 * mu1_mu2 + c1) / (mu1_sq + mu2_sq + c1)) * cs_map
+    return ssim_map.mean([1, 2, 3])

basicsr/models/__init__.py

+import importlib
+from copy import deepcopy
+from os import path as osp
+
+from basicsr.utils import get_root_logger, scandir
+from basicsr.utils.registry import MODEL_REGISTRY
+
+__all__ = ['build_model']
+
+# automatically scan and import model modules for registry
+# scan all the files under the 'models' folder and collect files ending with '_model.py'
+model_folder = osp.dirname(osp.abspath(__file__))
+model_filenames = [osp.splitext(osp.basename(v))[0] for v in scandir(model_folder) if v.endswith('_model.py')]
+# import all the model modules
+_model_modules = [importlib.import_module(f'basicsr.models.{file_name}') for file_name in model_filenames]
+
+
+def build_model(opt):
+    """Build model from options.
+
+    Args:
+        opt (dict): Configuration. It must contain:
+            model_type (str): Model type.
+    """
+    opt = deepcopy(opt)
+    model = MODEL_REGISTRY.get(opt['model_type'])(opt)
+    logger = get_root_logger()
+    logger.info(f'Model [{model.__class__.__name__}] is created.')
+    return model

basicsr/models/base_model.py

+import os
+import time
+import torch
+from collections import OrderedDict
+from copy import deepcopy
+from torch.nn.parallel import DataParallel, DistributedDataParallel
+
+from basicsr.models import lr_scheduler as lr_scheduler
+from basicsr.utils import get_root_logger
+from basicsr.utils.dist_util import master_only
+
+
+class BaseModel():
+    """Base model."""
+
+    def __init__(self, opt):
+        self.opt = opt
+        self.device = torch.device('cuda' if opt['num_gpu'] != 0 else 'cpu')
+        self.is_train = opt['is_train']
+        self.schedulers = []
+        self.optimizers = []
+
+    def feed_data(self, data):
+        pass
+
+    def optimize_parameters(self):
+        pass
+
+    def get_current_visuals(self):
+        pass
+
+    def save(self, epoch, current_iter):
+        """Save networks and training state."""
+        pass
+
+    def validation(self, dataloader, current_iter, tb_logger, save_img=False):
+        """Validation function.
+
+        Args:
+            dataloader (torch.utils.data.DataLoader): Validation dataloader.
+            current_iter (int): Current iteration.
+            tb_logger (tensorboard logger): Tensorboard logger.
+            save_img (bool): Whether to save images. Default: False.
+        """
+        if self.opt['dist']:
+            self.dist_validation(dataloader, current_iter, tb_logger, save_img)
+        else:
+            self.nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def _initialize_best_metric_results(self, dataset_name):
+        """Initialize the best metric results dict for recording the best metric value and iteration."""
+        if hasattr(self, 'best_metric_results') and dataset_name in self.best_metric_results:
+            return
+        elif not hasattr(self, 'best_metric_results'):
+            self.best_metric_results = dict()
+
+        # add a dataset record
+        record = dict()
+        for metric, content in self.opt['val']['metrics'].items():
+            better = content.get('better', 'higher')
+            init_val = float('-inf') if better == 'higher' else float('inf')
+            record[metric] = dict(better=better, val=init_val, iter=-1)
+        self.best_metric_results[dataset_name] = record
+
+    def _update_best_metric_result(self, dataset_name, metric, val, current_iter):
+        if self.best_metric_results[dataset_name][metric]['better'] == 'higher':
+            if val >= self.best_metric_results[dataset_name][metric]['val']:
+                self.best_metric_results[dataset_name][metric]['val'] = val
+                self.best_metric_results[dataset_name][metric]['iter'] = current_iter
+        else:
+            if val <= self.best_metric_results[dataset_name][metric]['val']:
+                self.best_metric_results[dataset_name][metric]['val'] = val
+                self.best_metric_results[dataset_name][metric]['iter'] = current_iter
+
+    def model_ema(self, decay=0.999):
+        net_g = self.get_bare_model(self.net_g)
+
+        net_g_params = dict(net_g.named_parameters())
+        net_g_ema_params = dict(self.net_g_ema.named_parameters())
+
+        for k in net_g_ema_params.keys():
+            net_g_ema_params[k].data.mul_(decay).add_(net_g_params[k].data, alpha=1 - decay)
+
+    def get_current_log(self):
+        return self.log_dict
+
+    def model_to_device(self, net):
+        """Model to device. It also warps models with DistributedDataParallel
+        or DataParallel.
+
+        Args:
+            net (nn.Module)
+        """
+        net = net.to(self.device)
+        if self.opt['dist']:
+            find_unused_parameters = self.opt.get('find_unused_parameters', False)
+            net = DistributedDataParallel(
+                net, device_ids=[torch.cuda.current_device()], find_unused_parameters=find_unused_parameters)
+        elif self.opt['num_gpu'] > 1:
+            net = DataParallel(net)
+        return net
+
+    def get_optimizer(self, optim_type, params, lr, **kwargs):
+        if optim_type == 'Adam':
+            optimizer = torch.optim.Adam(params, lr, **kwargs)
+        elif optim_type == 'AdamW':
+            optimizer = torch.optim.AdamW(params, lr, **kwargs)
+        elif optim_type == 'Adamax':
+            optimizer = torch.optim.Adamax(params, lr, **kwargs)
+        elif optim_type == 'SGD':
+            optimizer = torch.optim.SGD(params, lr, **kwargs)
+        elif optim_type == 'ASGD':
+            optimizer = torch.optim.ASGD(params, lr, **kwargs)
+        elif optim_type == 'RMSprop':
+            optimizer = torch.optim.RMSprop(params, lr, **kwargs)
+        elif optim_type == 'Rprop':
+            optimizer = torch.optim.Rprop(params, lr, **kwargs)
+        else:
+            raise NotImplementedError(f'optimizer {optim_type} is not supported yet.')
+        return optimizer
+
+    def setup_schedulers(self):
+        """Set up schedulers."""
+        train_opt = self.opt['train']
+        scheduler_type = train_opt['scheduler'].pop('type')
+        if scheduler_type in ['MultiStepLR', 'MultiStepRestartLR']:
+            for optimizer in self.optimizers:
+                self.schedulers.append(lr_scheduler.MultiStepRestartLR(optimizer, **train_opt['scheduler']))
+        elif scheduler_type == 'CosineAnnealingRestartLR':
+            for optimizer in self.optimizers:
+                self.schedulers.append(lr_scheduler.CosineAnnealingRestartLR(optimizer, **train_opt['scheduler']))
+        else:
+            raise NotImplementedError(f'Scheduler {scheduler_type} is not implemented yet.')
+
+    def get_bare_model(self, net):
+        """Get bare model, especially under wrapping with
+        DistributedDataParallel or DataParallel.
+        """
+        if isinstance(net, (DataParallel, DistributedDataParallel)):
+            net = net.module
+        return net
+
+    @master_only
+    def print_network(self, net):
+        """Print the str and parameter number of a network.
+
+        Args:
+            net (nn.Module)
+        """
+        if isinstance(net, (DataParallel, DistributedDataParallel)):
+            net_cls_str = f'{net.__class__.__name__} - {net.module.__class__.__name__}'
+        else:
+            net_cls_str = f'{net.__class__.__name__}'
+
+        net = self.get_bare_model(net)
+        net_str = str(net)
+        net_params = sum(map(lambda x: x.numel(), net.parameters()))
+
+        logger = get_root_logger()
+        logger.info(f'Network: {net_cls_str}, with parameters: {net_params:,d}')
+        logger.info(net_str)
+
+    def _set_lr(self, lr_groups_l):
+        """Set learning rate for warm-up.
+
+        Args:
+            lr_groups_l (list): List for lr_groups, each for an optimizer.
+        """
+        for optimizer, lr_groups in zip(self.optimizers, lr_groups_l):
+            for param_group, lr in zip(optimizer.param_groups, lr_groups):
+                param_group['lr'] = lr
+
+    def _get_init_lr(self):
+        """Get the initial lr, which is set by the scheduler.
+        """
+        init_lr_groups_l = []
+        for optimizer in self.optimizers:
+            init_lr_groups_l.append([v['initial_lr'] for v in optimizer.param_groups])
+        return init_lr_groups_l
+
+    def update_learning_rate(self, current_iter, warmup_iter=-1):
+        """Update learning rate.
+
+        Args:
+            current_iter (int): Current iteration.
+            warmup_iter (int)： Warm-up iter numbers. -1 for no warm-up.
+                Default： -1.
+        """
+        if current_iter > 1:
+            for scheduler in self.schedulers:
+                scheduler.step()
+        # set up warm-up learning rate
+        if current_iter < warmup_iter:
+            # get initial lr for each group
+            init_lr_g_l = self._get_init_lr()
+            # modify warming-up learning rates
+            # currently only support linearly warm up
+            warm_up_lr_l = []
+            for init_lr_g in init_lr_g_l:
+                warm_up_lr_l.append([v / warmup_iter * current_iter for v in init_lr_g])
+            # set learning rate
+            self._set_lr(warm_up_lr_l)
+
+    def get_current_learning_rate(self):
+        return [param_group['lr'] for param_group in self.optimizers[0].param_groups]
+
+    @master_only
+    def save_network(self, net, net_label, current_iter, param_key='params'):
+        """Save networks.
+
+        Args:
+            net (nn.Module | list[nn.Module]): Network(s) to be saved.
+            net_label (str): Network label.
+            current_iter (int): Current iter number.
+            param_key (str | list[str]): The parameter key(s) to save network.
+                Default: 'params'.
+        """
+        if current_iter == -1:
+            current_iter = 'latest'
+        save_filename = f'{net_label}_{current_iter}.pth'
+        save_path = os.path.join(self.opt['path']['models'], save_filename)
+
+        net = net if isinstance(net, list) else [net]
+        param_key = param_key if isinstance(param_key, list) else [param_key]
+        assert len(net) == len(param_key), 'The lengths of net and param_key should be the same.'
+
+        save_dict = {}
+        for net_, param_key_ in zip(net, param_key):
+            net_ = self.get_bare_model(net_)
+            state_dict = net_.state_dict()
+            for key, param in state_dict.items():
+                if key.startswith('module.'):  # remove unnecessary 'module.'
+                    key = key[7:]
+                state_dict[key] = param.cpu()
+            save_dict[param_key_] = state_dict
+
+        # avoid occasional writing errors
+        retry = 3
+        while retry > 0:
+            try:
+                torch.save(save_dict, save_path)
+            except Exception as e:
+                logger = get_root_logger()
+                logger.warning(f'Save model error: {e}, remaining retry times: {retry - 1}')
+                time.sleep(1)
+            else:
+                break
+            finally:
+                retry -= 1
+        if retry == 0:
+            logger.warning(f'Still cannot save {save_path}. Just ignore it.')
+            # raise IOError(f'Cannot save {save_path}.')
+
+    def _print_different_keys_loading(self, crt_net, load_net, strict=True):
+        """Print keys with different name or different size when loading models.
+
+        1. Print keys with different names.
+        2. If strict=False, print the same key but with different tensor size.
+            It also ignore these keys with different sizes (not load).
+
+        Args:
+            crt_net (torch model): Current network.
+            load_net (dict): Loaded network.
+            strict (bool): Whether strictly loaded. Default: True.
+        """
+        crt_net = self.get_bare_model(crt_net)
+        crt_net = crt_net.state_dict()
+        crt_net_keys = set(crt_net.keys())
+        load_net_keys = set(load_net.keys())
+
+        logger = get_root_logger()
+        if crt_net_keys != load_net_keys:
+            logger.warning('Current net - loaded net:')
+            for v in sorted(list(crt_net_keys - load_net_keys)):
+                logger.warning(f'  {v}')
+            logger.warning('Loaded net - current net:')
+            for v in sorted(list(load_net_keys - crt_net_keys)):
+                logger.warning(f'  {v}')
+
+        # check the size for the same keys
+        if not strict:
+            common_keys = crt_net_keys & load_net_keys
+            for k in common_keys:
+                if crt_net[k].size() != load_net[k].size():
+                    logger.warning(f'Size different, ignore [{k}]: crt_net: '
+                                   f'{crt_net[k].shape}; load_net: {load_net[k].shape}')
+                    load_net[k + '.ignore'] = load_net.pop(k)
+
+    def load_network(self, net, load_path, strict=True, param_key='params'):
+        """Load network.
+
+        Args:
+            load_path (str): The path of networks to be loaded.
+            net (nn.Module): Network.
+            strict (bool): Whether strictly loaded.
+            param_key (str): The parameter key of loaded network. If set to
+                None, use the root 'path'.
+                Default: 'params'.
+        """
+        logger = get_root_logger()
+        net = self.get_bare_model(net)
+        load_net = torch.load(load_path, map_location=lambda storage, loc: storage)
+        if param_key is not None:
+            if param_key not in load_net and 'params' in load_net:
+                param_key = 'params'
+                logger.info('Loading: params_ema does not exist, use params.')
+            load_net = load_net[param_key]
+        logger.info(f'Loading {net.__class__.__name__} model from {load_path}, with param key: [{param_key}].')
+        # remove unnecessary 'module.'
+        for k, v in deepcopy(load_net).items():
+            if k.startswith('module.'):
+                load_net[k[7:]] = v
+                load_net.pop(k)
+        self._print_different_keys_loading(net, load_net, strict)
+        net.load_state_dict(load_net, strict=strict)
+
+    @master_only
+    def save_training_state(self, epoch, current_iter):
+        """Save training states during training, which will be used for
+        resuming.
+
+        Args:
+            epoch (int): Current epoch.
+            current_iter (int): Current iteration.
+        """
+        if current_iter != -1:
+            state = {'epoch': epoch, 'iter': current_iter, 'optimizers': [], 'schedulers': []}
+            for o in self.optimizers:
+                state['optimizers'].append(o.state_dict())
+            for s in self.schedulers:
+                state['schedulers'].append(s.state_dict())
+            save_filename = f'{current_iter}.state'
+            save_path = os.path.join(self.opt['path']['training_states'], save_filename)
+
+            # avoid occasional writing errors
+            retry = 3
+            while retry > 0:
+                try:
+                    torch.save(state, save_path)
+                except Exception as e:
+                    logger = get_root_logger()
+                    logger.warning(f'Save training state error: {e}, remaining retry times: {retry - 1}')
+                    time.sleep(1)
+                else:
+                    break
+                finally:
+                    retry -= 1
+            if retry == 0:
+                logger.warning(f'Still cannot save {save_path}. Just ignore it.')
+                # raise IOError(f'Cannot save {save_path}.')
+
+    def resume_training(self, resume_state):
+        """Reload the optimizers and schedulers for resumed training.
+
+        Args:
+            resume_state (dict): Resume state.
+        """
+        resume_optimizers = resume_state['optimizers']
+        resume_schedulers = resume_state['schedulers']
+        assert len(resume_optimizers) == len(self.optimizers), 'Wrong lengths of optimizers'
+        assert len(resume_schedulers) == len(self.schedulers), 'Wrong lengths of schedulers'
+        for i, o in enumerate(resume_optimizers):
+            self.optimizers[i].load_state_dict(o)
+        for i, s in enumerate(resume_schedulers):
+            self.schedulers[i].load_state_dict(s)
+
+    def reduce_loss_dict(self, loss_dict):
+        """reduce loss dict.
+
+        In distributed training, it averages the losses among different GPUs .
+
+        Args:
+            loss_dict (OrderedDict): Loss dict.
+        """
+        with torch.no_grad():
+            if self.opt['dist']:
+                keys = []
+                losses = []
+                for name, value in loss_dict.items():
+                    keys.append(name)
+                    losses.append(value)
+                losses = torch.stack(losses, 0)
+                torch.distributed.reduce(losses, dst=0)
+                if self.opt['rank'] == 0:
+                    losses /= self.opt['world_size']
+                loss_dict = {key: loss for key, loss in zip(keys, losses)}
+
+            log_dict = OrderedDict()
+            for name, value in loss_dict.items():
+                log_dict[name] = value.mean().item()
+
+            return log_dict

basicsr/models/e2vsr_model.py

+import torch
+from collections import Counter
+from collections import OrderedDict
+from os import path as osp
+from torch import distributed as dist
+from tqdm import tqdm
+
+from basicsr.metrics import calculate_metric
+from basicsr.utils import get_root_logger, imwrite, tensor2img
+from basicsr.data.transforms import mod_crop
+from basicsr.utils.dist_util import get_dist_info
+from basicsr.utils.registry import MODEL_REGISTRY
+from .video_base_model import VideoBaseModel
+from torchvision import utils as vutils
+
+
+@MODEL_REGISTRY.register()
+class E2VSRModel(VideoBaseModel):
+
+    def __init__(self, opt):
+        super(E2VSRModel, self).__init__(opt)
+        self.scale = opt['scale']
+        if self.is_train:
+            self.fix_flow_iter = opt['train'].get('fix_flow')
+
+    def feed_data(self, data, flag='train'):
+        self.lq = data['lq'].to(self.device)
+        self.voxels_f = data['voxels_f'].to(self.device)
+        self.voxels_b = data['voxels_b'].to(self.device)
+        if 'gt' in data:
+            self.gt = data['gt'].to(self.device)
+
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        flow_lr_mul = train_opt.get('flow_lr_mul', 1)
+        logger = get_root_logger()
+        logger.info(f'Multiple the learning rate for flow network with {flow_lr_mul}.')
+        if flow_lr_mul == 1:
+            optim_params = self.net_g.parameters()
+        else:  # separate flow params and normal params for different lr
+            normal_params = []
+            flow_params = []
+            for name, param in self.net_g.named_parameters():
+                # if 'spynet' in name or (self.is_pretrain and 'unet' in name):
+                if 'spynet' in name:
+                    flow_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+                {
+                    'params': flow_params,
+                    'lr': train_opt['optim_g']['lr'] * flow_lr_mul
+                },
+            ]
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def optimize_parameters(self, current_iter):
+        if self.fix_flow_iter:
+            logger = get_root_logger()
+            if current_iter == 1:
+                logger.info(f'Fix flow network and feature extractor for {self.fix_flow_iter} iters.')
+                for name, param in self.net_g.named_parameters():
+                    # if 'spynet' in name or 'edvr' in name or (self.is_pretrain and 'unet' in name):
+                    if 'spynet' in name or 'edvr' in name:
+                        param.requires_grad_(False)
+            elif current_iter == self.fix_flow_iter:
+                logger.warning('Train all the parameters.')
+                self.net_g.requires_grad_(True)
+
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq, self.voxels_f, self.voxels_b)
+
+        l_total = 0
+        loss_dict = OrderedDict()
+        # pixel loss
+        if self.cri_pix:
+            l_pix = self.cri_pix(self.output, self.gt)
+            l_total += l_pix
+            loss_dict['l_pix'] = l_pix
+        # perceptual loss
+        if self.cri_perceptual:
+            l_percep, l_style = self.cri_perceptual(self.output, self.gt)
+            if l_percep is not None:
+                l_total += l_percep
+                loss_dict['l_percep'] = l_percep
+            if l_style is not None:
+                l_total += l_style
+                loss_dict['l_style'] = l_style
+
+        loss_dict['l_total'] = l_total
+        l_total.backward()
+        self.optimizer_g.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset = dataloader.dataset
+        dataset_name = dataset.opt['name']
+        with_metrics = self.opt['val']['metrics'] is not None
+        # initialize self.metric_results
+        # It is a dict: {
+        #    'folder1': tensor (num_frame x len(metrics)),
+        #    'folder2': tensor (num_frame x len(metrics))
+        # }
+        if with_metrics:
+            # if not hasattr(self, 'metric_results'):  # only execute in the first run
+            self.metric_results = {}
+            num_frame_each_folder = Counter(dataset.data_info['folder'])
+            for folder, num_frame in num_frame_each_folder.items():
+                self.metric_results[folder] = torch.zeros(
+                    num_frame, len(self.opt['val']['metrics']), dtype=torch.float32, device='cuda')
+            # initialize the best metric results
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        rank, world_size = get_dist_info()
+        if with_metrics:
+            for _, tensor in self.metric_results.items():
+                tensor.zero_()
+
+        metric_data = dict()
+        num_folders = len(dataset)
+        num_pad = (world_size - (num_folders % world_size)) % world_size
+        if rank == 0:
+            pbar = tqdm(total=len(dataset), unit='folder')
+        # Will evaluate (num_folders + num_pad) times, but only the first num_folders results will be recorded.
+        # (To avoid wait-dead)
+        for i in range(rank, num_folders + num_pad, world_size):
+            idx = min(i, num_folders - 1)
+            val_data = dataset[idx]
+            folder = val_data['folder']
+
+            # compute outputs
+            val_data['lq'].unsqueeze_(0)
+            val_data['gt'].unsqueeze_(0)
+            val_data['voxels_f'].unsqueeze_(0)
+            val_data['voxels_b'].unsqueeze_(0)
+            self.feed_data(val_data,  flag='val')
+            val_data['lq'].squeeze_(0)
+            val_data['gt'].squeeze_(0)
+            val_data['voxels_f'].squeeze_(0)
+            val_data['voxels_b'].squeeze_(0)
+
+            self.test()
+            visuals = self.get_current_visuals()
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            del self.voxels_f
+            del self.voxels_b
+            if 'gt' in visuals:
+                del self.gt
+            torch.cuda.empty_cache()
+
+            # evaluate
+            if i < num_folders:
+                for idx in range(visuals['result'].size(1)):
+                    result_img = visuals['result'][0, idx, :, :, :]
+                    result_img = tensor2img([result_img])  # uint8, bgr
+                    # metric_data['img'] = result_img
+                    # if 'gt' in visuals:
+                    #     gt = visuals['gt'][0, idx, :, :, :]
+                    #     gt_img = tensor2img([gt])  # uint8, bgr
+                    #     gt_img = mod_crop(gt_img, self.scale)
+                    #     metric_data['img2'] = gt_img
+
+                    # # calculate metrics
+                    # if with_metrics:
+                    #     for metric_idx, opt_ in enumerate(self.opt['val']['metrics'].values()):
+                    #         result = calculate_metric(metric_data, opt_)
+                    #         self.metric_results[folder][idx, metric_idx] += result
+
+                    if save_img:
+                        if self.opt['is_train']:
+                            raise NotImplementedError('saving image is not supported during training.')
+                        else:
+                            # temp_psnr = self.metric_results[folder][idx, 0]
+                            # img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                            #                     osp.splitext(folder)[0],
+                            #                     f"{idx:06d}_{temp_psnr:.4f}_{self.opt['name']}.png")
+                            img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                osp.splitext(folder)[0],
+                                                f"{idx:06d}_{self.opt['name']}.png")
+                        imwrite(result_img, img_path)
+
+                # progress bar
+                if rank == 0:
+                    for _ in range(world_size):
+                        pbar.update(1)
+                        pbar.set_description(f'Folder: {folder}')
+
+        if rank == 0:
+            pbar.close()
+
+        if with_metrics:
+            if self.opt['dist']:
+                # collect data among GPUs
+                for _, tensor in self.metric_results.items():
+                    dist.reduce(tensor, 0)
+                dist.barrier()
+
+            if rank == 0:
+                self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def test(self):
+        n = self.lq.size(1)
+        self.net_g.eval()
+
+        with torch.no_grad():
+            self.output = self.net_g(self.lq, self.voxels_f, self.voxels_b)
+
+        self.net_g.train()
+
+    def get_current_visuals(self):
+        out_dict = OrderedDict()
+        out_dict['lq'] = self.lq.detach().cpu()
+        out_dict['result'] = self.output.detach().cpu()
+        if hasattr(self, 'gt'):
+            out_dict['gt'] = self.gt.detach().cpu()
+        return out_dict
+
+    def _log_validation_metric_values(self, current_iter, dataset_name, tb_logger):
+        # ----------------- calculate the average values for each folder, and for each metric  ----------------- #
+        # average all frames for each sub-folder
+        # metric_results_avg is a dict:{
+        #    folder example: 'people_dynamic_wave/split0'
+        #    'folder1': tensor (len(metrics)),
+        #    'folder2': tensor (len(metrics))
+        # }
+        metric_results_avg = {
+            folder: torch.mean(tensor, dim=0).cpu()
+            for (folder, tensor) in self.metric_results.items()
+        }
+
+        # cnt_folder is a dict:{
+        #    'folder1': int (len(folder1))
+        #    'folder2': int (len(folder2))
+        # }
+        cnt_folder = {folder: tensor.size(0) for (folder, tensor) in self.metric_results.items()}
+        # total_avg_results is a dict: {
+        #    'metric1': float,
+        #    'metric2': float
+        # }
+        total_avg_results = {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+        for folder, tensor in metric_results_avg.items():
+            for metric_idx, metric in enumerate(total_avg_results.keys()):
+                total_avg_results[metric] += tensor[metric_idx].item() * cnt_folder[folder]
+
+        total_samples_length = 0
+        for folder, length in cnt_folder.items():
+            total_samples_length += length
+
+        # average among folders
+        for metric in total_avg_results.keys():
+            total_avg_results[metric] /= total_samples_length
+            # update the best metric result
+            self._update_best_metric_result(dataset_name, metric, total_avg_results[metric], current_iter)
+
+        # ------------------------------------------ log the metric ------------------------------------------ #
+        log_str = f'Validation {dataset_name}\n'
+
+        for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+            log_str += f'\t # {metric}: {value:.4f}'
+            for folder, tensor in metric_results_avg.items():
+                report_folder = folder.split('.')[0]
+                log_str += f'\t # {report_folder}: {tensor[metric_idx].item():.4f}'
+            if hasattr(self, 'best_metric_results'):
+                log_str += (f'\n\t    Best: {self.best_metric_results[dataset_name][metric]["val"]:.4f} @ '
+                            f'{self.best_metric_results[dataset_name][metric]["iter"]} iter')
+            log_str += '\n'
+
+        logger = get_root_logger()
+        logger.info(log_str)
+        if tb_logger:
+            for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+                tb_logger.add_scalar(f'metrics/{metric}', value, current_iter)
+                for folder, tensor in metric_results_avg.items():
+                    tb_logger.add_scalar(f'metrics/{metric}/{folder}', tensor[metric_idx].item(), current_iter)
\ No newline at end of file

basicsr/models/lr_scheduler.py

+import math
+from collections import Counter
+from torch.optim.lr_scheduler import _LRScheduler
+
+
+class MultiStepRestartLR(_LRScheduler):
+    """ MultiStep with restarts learning rate scheme.
+
+    Args:
+        optimizer (torch.nn.optimizer): Torch optimizer.
+        milestones (list): Iterations that will decrease learning rate.
+        gamma (float): Decrease ratio. Default: 0.1.
+        restarts (list): Restart iterations. Default: [0].
+        restart_weights (list): Restart weights at each restart iteration.
+            Default: [1].
+        last_epoch (int): Used in _LRScheduler. Default: -1.
+    """
+
+    def __init__(self, optimizer, milestones, gamma=0.1, restarts=(0, ), restart_weights=(1, ), last_epoch=-1):
+        self.milestones = Counter(milestones)
+        self.gamma = gamma
+        self.restarts = restarts
+        self.restart_weights = restart_weights
+        assert len(self.restarts) == len(self.restart_weights), 'restarts and their weights do not match.'
+        super(MultiStepRestartLR, self).__init__(optimizer, last_epoch)
+
+    def get_lr(self):
+        if self.last_epoch in self.restarts:
+            weight = self.restart_weights[self.restarts.index(self.last_epoch)]
+            return [group['initial_lr'] * weight for group in self.optimizer.param_groups]
+        if self.last_epoch not in self.milestones:
+            return [group['lr'] for group in self.optimizer.param_groups]
+        return [group['lr'] * self.gamma**self.milestones[self.last_epoch] for group in self.optimizer.param_groups]
+
+
+def get_position_from_periods(iteration, cumulative_period):
+    """Get the position from a period list.
+
+    It will return the index of the right-closest number in the period list.
+    For example, the cumulative_period = [100, 200, 300, 400],
+    if iteration == 50, return 0;
+    if iteration == 210, return 2;
+    if iteration == 300, return 2.
+
+    Args:
+        iteration (int): Current iteration.
+        cumulative_period (list[int]): Cumulative period list.
+
+    Returns:
+        int: The position of the right-closest number in the period list.
+    """
+    for i, period in enumerate(cumulative_period):
+        if iteration <= period:
+            return i
+
+
+class CosineAnnealingRestartLR(_LRScheduler):
+    """ Cosine annealing with restarts learning rate scheme.
+
+    An example of config:
+    periods = [10, 10, 10, 10]
+    restart_weights = [1, 0.5, 0.5, 0.5]
+    eta_min=1e-7
+
+    It has four cycles, each has 10 iterations. At 10th, 20th, 30th, the
+    scheduler will restart with the weights in restart_weights.
+
+    Args:
+        optimizer (torch.nn.optimizer): Torch optimizer.
+        periods (list): Period for each cosine anneling cycle.
+        restart_weights (list): Restart weights at each restart iteration.
+            Default: [1].
+        eta_min (float): The minimum lr. Default: 0.
+        last_epoch (int): Used in _LRScheduler. Default: -1.
+    """
+
+    def __init__(self, optimizer, periods, restart_weights=(1, ), eta_min=0, last_epoch=-1):
+        self.periods = periods
+        self.restart_weights = restart_weights
+        self.eta_min = eta_min
+        assert (len(self.periods) == len(
+            self.restart_weights)), 'periods and restart_weights should have the same length.'
+        self.cumulative_period = [sum(self.periods[0:i + 1]) for i in range(0, len(self.periods))]
+        super(CosineAnnealingRestartLR, self).__init__(optimizer, last_epoch)
+
+    def get_lr(self):
+        idx = get_position_from_periods(self.last_epoch, self.cumulative_period)
+        current_weight = self.restart_weights[idx]
+        nearest_restart = 0 if idx == 0 else self.cumulative_period[idx - 1]
+        current_period = self.periods[idx]
+
+        return [
+            self.eta_min + current_weight * 0.5 * (base_lr - self.eta_min) *
+            (1 + math.cos(math.pi * ((self.last_epoch - nearest_restart) / current_period)))
+            for base_lr in self.base_lrs
+        ]

basicsr/models/sr_model.py

+import torch
+from collections import OrderedDict
+from os import path as osp
+from tqdm import tqdm
+
+from basicsr.archs import build_network
+from basicsr.losses import build_loss
+from basicsr.metrics import calculate_metric
+from basicsr.utils import get_root_logger, imwrite, tensor2img
+from basicsr.utils.registry import MODEL_REGISTRY
+from .base_model import BaseModel
+
+
+@MODEL_REGISTRY.register()
+class SRModel(BaseModel):
+    """Base SR model for single image super-resolution."""
+
+    def __init__(self, opt):
+        super(SRModel, self).__init__(opt)
+
+        # define network
+        self.net_g = build_network(opt['network_g'])
+        self.net_g = self.model_to_device(self.net_g)
+        self.print_network(self.net_g)
+
+        # load pretrained models
+        load_path = self.opt['path'].get('pretrain_network_g', None)
+        if load_path is not None:
+            param_key = self.opt['path'].get('param_key_g', 'params')
+            self.load_network(self.net_g, load_path, self.opt['path'].get('strict_load_g', True), param_key)
+
+        if self.is_train:
+            self.init_training_settings()
+
+    def init_training_settings(self):
+        self.net_g.train()
+        train_opt = self.opt['train']
+
+        self.ema_decay = train_opt.get('ema_decay', 0)
+        if self.ema_decay > 0:
+            logger = get_root_logger()
+            logger.info(f'Use Exponential Moving Average with decay: {self.ema_decay}')
+            # define network net_g with Exponential Moving Average (EMA)
+            # net_g_ema is used only for testing on one GPU and saving
+            # There is no need to wrap with DistributedDataParallel
+            self.net_g_ema = build_network(self.opt['network_g']).to(self.device)
+            # load pretrained model
+            load_path = self.opt['path'].get('pretrain_network_g', None)
+            if load_path is not None:
+                self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema')
+            else:
+                self.model_ema(0)  # copy net_g weight
+            self.net_g_ema.eval()
+
+        # define losses
+        if train_opt.get('pixel_opt'):
+            self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device)
+        else:
+            self.cri_pix = None
+
+        if train_opt.get('perceptual_opt'):
+            self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device)
+        else:
+            self.cri_perceptual = None
+
+        if self.cri_pix is None and self.cri_perceptual is None:
+            raise ValueError('Both pixel and perceptual losses are None.')
+
+        # set up optimizers and schedulers
+        self.setup_optimizers()
+        self.setup_schedulers()
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        optim_params = []
+        for k, v in self.net_g.named_parameters():
+            if v.requires_grad:
+                optim_params.append(v)
+            else:
+                logger = get_root_logger()
+                logger.warning(f'Params {k} will not be optimized.')
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def feed_data(self, data):
+        self.lq = data['lq'].to(self.device)
+        if 'gt' in data:
+            self.gt = data['gt'].to(self.device)
+
+    def optimize_parameters(self, current_iter):
+        self.optimizer_g.zero_grad()
+        self.output = self.net_g(self.lq)
+
+        l_total = 0
+        loss_dict = OrderedDict()
+        # pixel loss
+        if self.cri_pix:
+            l_pix = self.cri_pix(self.output, self.gt)
+            l_total += l_pix
+            loss_dict['l_pix'] = l_pix
+        # perceptual loss
+        if self.cri_perceptual:
+            l_percep, l_style = self.cri_perceptual(self.output, self.gt)
+            if l_percep is not None:
+                l_total += l_percep
+                loss_dict['l_percep'] = l_percep
+            if l_style is not None:
+                l_total += l_style
+                loss_dict['l_style'] = l_style
+
+        l_total.backward()
+        self.optimizer_g.step()
+
+        self.log_dict = self.reduce_loss_dict(loss_dict)
+
+        if self.ema_decay > 0:
+            self.model_ema(decay=self.ema_decay)
+
+    def test(self):
+        if hasattr(self, 'net_g_ema'):
+            self.net_g_ema.eval()
+            with torch.no_grad():
+                self.output = self.net_g_ema(self.lq)
+        else:
+            self.net_g.eval()
+            with torch.no_grad():
+                self.output = self.net_g(self.lq)
+            self.net_g.train()
+
+    def test_selfensemble(self):
+        # TODO: to be tested
+        # 8 augmentations
+        # modified from https://github.com/thstkdgus35/EDSR-PyTorch
+
+        def _transform(v, op):
+            # if self.precision != 'single': v = v.float()
+            v2np = v.data.cpu().numpy()
+            if op == 'v':
+                tfnp = v2np[:, :, :, ::-1].copy()
+            elif op == 'h':
+                tfnp = v2np[:, :, ::-1, :].copy()
+            elif op == 't':
+                tfnp = v2np.transpose((0, 1, 3, 2)).copy()
+
+            ret = torch.Tensor(tfnp).to(self.device)
+            # if self.precision == 'half': ret = ret.half()
+
+            return ret
+
+        # prepare augmented data
+        lq_list = [self.lq]
+        for tf in 'v', 'h', 't':
+            lq_list.extend([_transform(t, tf) for t in lq_list])
+
+        # inference
+        if hasattr(self, 'net_g_ema'):
+            self.net_g_ema.eval()
+            with torch.no_grad():
+                out_list = [self.net_g_ema(aug) for aug in lq_list]
+        else:
+            self.net_g.eval()
+            with torch.no_grad():
+                out_list = [self.net_g_ema(aug) for aug in lq_list]
+            self.net_g.train()
+
+        # merge results
+        for i in range(len(out_list)):
+            if i > 3:
+                out_list[i] = _transform(out_list[i], 't')
+            if i % 4 > 1:
+                out_list[i] = _transform(out_list[i], 'h')
+            if (i % 4) % 2 == 1:
+                out_list[i] = _transform(out_list[i], 'v')
+        output = torch.cat(out_list, dim=0)
+
+        self.output = output.mean(dim=0, keepdim=True)
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        if self.opt['rank'] == 0:
+            self.nondist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset_name = dataloader.dataset.opt['name']
+        with_metrics = self.opt['val'].get('metrics') is not None
+        use_pbar = self.opt['val'].get('pbar', False)
+
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+            # initialize the best metric results for each dataset_name (supporting multiple validation datasets)
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        if with_metrics:
+            self.metric_results = {metric: 0 for metric in self.metric_results}
+
+        metric_data = dict()
+        if use_pbar:
+            pbar = tqdm(total=len(dataloader), unit='image')
+
+        for idx, val_data in enumerate(dataloader):
+            img_name = osp.splitext(osp.basename(val_data['lq_path'][0]))[0]
+            self.feed_data(val_data)
+            self.test()
+
+            visuals = self.get_current_visuals()
+            sr_img = tensor2img([visuals['result']])
+            metric_data['img'] = sr_img
+            if 'gt' in visuals:
+                gt_img = tensor2img([visuals['gt']])
+                metric_data['img2'] = gt_img
+                del self.gt
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            torch.cuda.empty_cache()
+
+            if save_img:
+                if self.opt['is_train']:
+                    save_img_path = osp.join(self.opt['path']['visualization'], img_name,
+                                             f'{img_name}_{current_iter}.png')
+                else:
+                    if self.opt['val']['suffix']:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["val"]["suffix"]}.png')
+                    else:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name,
+                                                 f'{img_name}_{self.opt["name"]}.png')
+                imwrite(sr_img, save_img_path)
+
+            if with_metrics:
+                # calculate metrics
+                for name, opt_ in self.opt['val']['metrics'].items():
+                    self.metric_results[name] += calculate_metric(metric_data, opt_)
+            if use_pbar:
+                pbar.update(1)
+                pbar.set_description(f'Test {img_name}')
+        if use_pbar:
+            pbar.close()
+
+        if with_metrics:
+            for metric in self.metric_results.keys():
+                self.metric_results[metric] /= (idx + 1)
+                # update the best metric result
+                self._update_best_metric_result(dataset_name, metric, self.metric_results[metric], current_iter)
+
+            self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def _log_validation_metric_values(self, current_iter, dataset_name, tb_logger):
+        log_str = f'Validation {dataset_name}\n'
+        for metric, value in self.metric_results.items():
+            log_str += f'\t # {metric}: {value:.4f}'
+            if hasattr(self, 'best_metric_results'):
+                log_str += (f'\tBest: {self.best_metric_results[dataset_name][metric]["val"]:.4f} @ '
+                            f'{self.best_metric_results[dataset_name][metric]["iter"]} iter')
+            log_str += '\n'
+
+        logger = get_root_logger()
+        logger.info(log_str)
+        if tb_logger:
+            for metric, value in self.metric_results.items():
+                tb_logger.add_scalar(f'metrics/{dataset_name}/{metric}', value, current_iter)
+
+    def get_current_visuals(self):
+        out_dict = OrderedDict()
+        out_dict['lq'] = self.lq.detach().cpu()
+        out_dict['result'] = self.output.detach().cpu()
+        if hasattr(self, 'gt'):
+            out_dict['gt'] = self.gt.detach().cpu()
+        return out_dict
+
+    def save(self, epoch, current_iter):
+        if hasattr(self, 'net_g_ema'):
+            self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema'])
+        else:
+            self.save_network(self.net_g, 'net_g', current_iter)
+        self.save_training_state(epoch, current_iter)

basicsr/models/video_base_model.py

+import torch
+from collections import Counter
+from os import path as osp
+from torch import distributed as dist
+from tqdm import tqdm
+
+from basicsr.metrics import calculate_metric
+from basicsr.utils import get_root_logger, imwrite, tensor2img
+from basicsr.utils.dist_util import get_dist_info
+from basicsr.utils.registry import MODEL_REGISTRY
+from .sr_model import SRModel
+
+
+@MODEL_REGISTRY.register()
+class VideoBaseModel(SRModel):
+    """Base video SR model."""
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset = dataloader.dataset
+        dataset_name = dataset.opt['name']
+        with_metrics = self.opt['val']['metrics'] is not None
+        # initialize self.metric_results
+        # It is a dict: {
+        #    'folder1': tensor (num_frame x len(metrics)),
+        #    'folder2': tensor (num_frame x len(metrics))
+        # }
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {}
+                num_frame_each_folder = Counter(dataset.data_info['folder'])
+                for folder, num_frame in num_frame_each_folder.items():
+                    self.metric_results[folder] = torch.zeros(
+                        num_frame, len(self.opt['val']['metrics']), dtype=torch.float32, device='cuda')
+            # initialize the best metric results
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        rank, world_size = get_dist_info()
+        if with_metrics:
+            for _, tensor in self.metric_results.items():
+                tensor.zero_()
+
+        metric_data = dict()
+        # record all frames (border and center frames)
+        if rank == 0:
+            pbar = tqdm(total=len(dataset), unit='frame')
+        for idx in range(rank, len(dataset), world_size):
+            val_data = dataset[idx]
+            val_data['lq'].unsqueeze_(0)
+            val_data['gt'].unsqueeze_(0)
+            folder = val_data['folder']
+            frame_idx, max_idx = val_data['idx'].split('/')
+            lq_path = val_data['lq_path']
+
+            self.feed_data(val_data)
+            self.test()
+            visuals = self.get_current_visuals()
+            result_img = tensor2img([visuals['result']])
+            metric_data['img'] = result_img
+            if 'gt' in visuals:
+                gt_img = tensor2img([visuals['gt']])
+                metric_data['img2'] = gt_img
+                del self.gt
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            torch.cuda.empty_cache()
+
+            if save_img:
+                if self.opt['is_train']:
+                    raise NotImplementedError('saving image is not supported during training.')
+                else:
+                    if 'vimeo' in dataset_name.lower():  # vimeo90k dataset
+                        split_result = lq_path.split('/')
+                        img_name = f'{split_result[-3]}_{split_result[-2]}_{split_result[-1].split(".")[0]}'
+                    else:  # other datasets, e.g., REDS, Vid4
+                        img_name = osp.splitext(osp.basename(lq_path))[0]
+
+                    if self.opt['val']['suffix']:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                 f'{img_name}_{self.opt["val"]["suffix"]}.png')
+                    else:
+                        save_img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                 f'{img_name}_{self.opt["name"]}.png')
+                imwrite(result_img, save_img_path)
+
+            if with_metrics:
+                # calculate metrics
+                for metric_idx, opt_ in enumerate(self.opt['val']['metrics'].values()):
+                    result = calculate_metric(metric_data, opt_)
+                    self.metric_results[folder][int(frame_idx), metric_idx] += result
+
+            # progress bar
+            if rank == 0:
+                for _ in range(world_size):
+                    pbar.update(1)
+                    pbar.set_description(f'Test {folder}: {int(frame_idx) + world_size}/{max_idx}')
+        if rank == 0:
+            pbar.close()
+
+        if with_metrics:
+            if self.opt['dist']:
+                # collect data among GPUs
+                for _, tensor in self.metric_results.items():
+                    dist.reduce(tensor, 0)
+                dist.barrier()
+            else:
+                pass  # assume use one gpu in non-dist testing
+
+            if rank == 0:
+                self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def nondist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        logger = get_root_logger()
+        logger.warning('nondist_validation is not implemented. Run dist_validation.')
+        self.dist_validation(dataloader, current_iter, tb_logger, save_img)
+
+    def _log_validation_metric_values(self, current_iter, dataset_name, tb_logger):
+        # ----------------- calculate the average values for each folder, and for each metric  ----------------- #
+        # average all frames for each sub-folder
+        # metric_results_avg is a dict:{
+        #    'folder1': tensor (len(metrics)),
+        #    'folder2': tensor (len(metrics))
+        # }
+        metric_results_avg = {
+            folder: torch.mean(tensor, dim=0).cpu()
+            for (folder, tensor) in self.metric_results.items()
+        }
+        # total_avg_results is a dict: {
+        #    'metric1': float,
+        #    'metric2': float
+        # }
+        total_avg_results = {metric: 0 for metric in self.opt['val']['metrics'].keys()}
+        for folder, tensor in metric_results_avg.items():
+            for idx, metric in enumerate(total_avg_results.keys()):
+                total_avg_results[metric] += metric_results_avg[folder][idx].item()
+        # average among folders
+        for metric in total_avg_results.keys():
+            total_avg_results[metric] /= len(metric_results_avg)
+            # update the best metric result
+            self._update_best_metric_result(dataset_name, metric, total_avg_results[metric], current_iter)
+
+        # ------------------------------------------ log the metric ------------------------------------------ #
+        log_str = f'Validation {dataset_name}\n'
+        for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+            log_str += f'\t # {metric}: {value:.4f}'
+            for folder, tensor in metric_results_avg.items():
+                log_str += f'\t # {folder}: {tensor[metric_idx].item():.4f}'
+            if hasattr(self, 'best_metric_results'):
+                log_str += (f'\n\t    Best: {self.best_metric_results[dataset_name][metric]["val"]:.4f} @ '
+                            f'{self.best_metric_results[dataset_name][metric]["iter"]} iter')
+            log_str += '\n'
+
+        logger = get_root_logger()
+        logger.info(log_str)
+        if tb_logger:
+            for metric_idx, (metric, value) in enumerate(total_avg_results.items()):
+                tb_logger.add_scalar(f'metrics/{metric}', value, current_iter)
+                for folder, tensor in metric_results_avg.items():
+                    tb_logger.add_scalar(f'metrics/{metric}/{folder}', tensor[metric_idx].item(), current_iter)

basicsr/models/video_recurrent_model.py

+import torch
+from collections import Counter
+from os import path as osp
+from torch import distributed as dist
+from tqdm import tqdm
+
+from basicsr.metrics import calculate_metric
+from basicsr.utils import get_root_logger, imwrite, tensor2img
+from basicsr.utils.dist_util import get_dist_info
+from basicsr.utils.registry import MODEL_REGISTRY
+from .video_base_model import VideoBaseModel
+
+
+@MODEL_REGISTRY.register()
+class VideoRecurrentModel(VideoBaseModel):
+
+    def __init__(self, opt):
+        super(VideoRecurrentModel, self).__init__(opt)
+        if self.is_train:
+            self.fix_flow_iter = opt['train'].get('fix_flow')
+
+    def setup_optimizers(self):
+        train_opt = self.opt['train']
+        flow_lr_mul = train_opt.get('flow_lr_mul', 1)
+        logger = get_root_logger()
+        logger.info(f'Multiple the learning rate for flow network with {flow_lr_mul}.')
+        if flow_lr_mul == 1:
+            optim_params = self.net_g.parameters()
+        else:  # separate flow params and normal params for different lr
+            normal_params = []
+            flow_params = []
+            for name, param in self.net_g.named_parameters():
+                if 'spynet' in name:
+                    flow_params.append(param)
+                else:
+                    normal_params.append(param)
+            optim_params = [
+                {  # add normal params first
+                    'params': normal_params,
+                    'lr': train_opt['optim_g']['lr']
+                },
+                {
+                    'params': flow_params,
+                    'lr': train_opt['optim_g']['lr'] * flow_lr_mul
+                },
+            ]
+
+        optim_type = train_opt['optim_g'].pop('type')
+        self.optimizer_g = self.get_optimizer(optim_type, optim_params, **train_opt['optim_g'])
+        self.optimizers.append(self.optimizer_g)
+
+    def optimize_parameters(self, current_iter):
+        if self.fix_flow_iter:
+            logger = get_root_logger()
+            if current_iter == 1:
+                logger.info(f'Fix flow network and feature extractor for {self.fix_flow_iter} iters.')
+                for name, param in self.net_g.named_parameters():
+                    if 'spynet' in name or 'edvr' in name:
+                        param.requires_grad_(False)
+            elif current_iter == self.fix_flow_iter:
+                logger.warning('Train all the parameters.')
+                self.net_g.requires_grad_(True)
+
+        super(VideoRecurrentModel, self).optimize_parameters(current_iter)
+
+    def dist_validation(self, dataloader, current_iter, tb_logger, save_img):
+        dataset = dataloader.dataset
+        dataset_name = dataset.opt['name']
+        with_metrics = self.opt['val']['metrics'] is not None
+        # initialize self.metric_results
+        # It is a dict: {
+        #    'folder1': tensor (num_frame x len(metrics)),
+        #    'folder2': tensor (num_frame x len(metrics))
+        # }
+        if with_metrics:
+            if not hasattr(self, 'metric_results'):  # only execute in the first run
+                self.metric_results = {}
+                num_frame_each_folder = Counter(dataset.data_info['folder'])
+                for folder, num_frame in num_frame_each_folder.items():
+                    self.metric_results[folder] = torch.zeros(
+                        num_frame, len(self.opt['val']['metrics']), dtype=torch.float32, device='cuda')
+            # initialize the best metric results
+            self._initialize_best_metric_results(dataset_name)
+        # zero self.metric_results
+        rank, world_size = get_dist_info()
+        if with_metrics:
+            for _, tensor in self.metric_results.items():
+                tensor.zero_()
+
+        metric_data = dict()
+        num_folders = len(dataset)
+        num_pad = (world_size - (num_folders % world_size)) % world_size
+        if rank == 0:
+            pbar = tqdm(total=len(dataset), unit='folder')
+        # Will evaluate (num_folders + num_pad) times, but only the first num_folders results will be recorded.
+        # (To avoid wait-dead)
+        for i in range(rank, num_folders + num_pad, world_size):
+            idx = min(i, num_folders - 1)
+            val_data = dataset[idx]
+            folder = val_data['folder']
+
+            # compute outputs
+            val_data['lq'].unsqueeze_(0)
+            val_data['gt'].unsqueeze_(0)
+            self.feed_data(val_data)
+            val_data['lq'].squeeze_(0)
+            val_data['gt'].squeeze_(0)
+
+            self.test()
+            visuals = self.get_current_visuals()
+
+            # tentative for out of GPU memory
+            del self.lq
+            del self.output
+            if 'gt' in visuals:
+                del self.gt
+            torch.cuda.empty_cache()
+
+            if self.center_frame_only:
+                visuals['result'] = visuals['result'].unsqueeze(1)
+                if 'gt' in visuals:
+                    visuals['gt'] = visuals['gt'].unsqueeze(1)
+
+            # evaluate
+            if i < num_folders:
+                for idx in range(visuals['result'].size(1)):
+                    result = visuals['result'][0, idx, :, :, :]
+                    result_img = tensor2img([result])  # uint8, bgr
+                    metric_data['img'] = result_img
+                    if 'gt' in visuals:
+                        gt = visuals['gt'][0, idx, :, :, :]
+                        gt_img = tensor2img([gt])  # uint8, bgr
+                        metric_data['img2'] = gt_img
+
+                    if save_img:
+                        if self.opt['is_train']:
+                            raise NotImplementedError('saving image is not supported during training.')
+                        else:
+                            if self.center_frame_only:  # vimeo-90k
+                                clip_ = val_data['lq_path'].split('/')[-3]
+                                seq_ = val_data['lq_path'].split('/')[-2]
+                                name_ = f'{clip_}_{seq_}'
+                                img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                    f"{name_}_{self.opt['name']}.png")
+                            else:  # others
+                                img_path = osp.join(self.opt['path']['visualization'], dataset_name, folder,
+                                                    f"{idx:08d}_{self.opt['name']}.png")
+                            # image name only for REDS dataset
+                        imwrite(result_img, img_path)
+
+                    # calculate metrics
+                    if with_metrics:
+                        for metric_idx, opt_ in enumerate(self.opt['val']['metrics'].values()):
+                            result = calculate_metric(metric_data, opt_)
+                            self.metric_results[folder][idx, metric_idx] += result
+
+                # progress bar
+                if rank == 0:
+                    for _ in range(world_size):
+                        pbar.update(1)
+                        pbar.set_description(f'Folder: {folder}')
+
+        if rank == 0:
+            pbar.close()
+
+        if with_metrics:
+            if self.opt['dist']:
+                # collect data among GPUs
+                for _, tensor in self.metric_results.items():
+                    dist.reduce(tensor, 0)
+                dist.barrier()
+
+            if rank == 0:
+                self._log_validation_metric_values(current_iter, dataset_name, tb_logger)
+
+    def test(self):
+        n = self.lq.size(1)
+        self.net_g.eval()
+
+        flip_seq = self.opt['val'].get('flip_seq', False)
+        self.center_frame_only = self.opt['val'].get('center_frame_only', False)
+
+        if flip_seq:
+            self.lq = torch.cat([self.lq, self.lq.flip(1)], dim=1)
+
+        with torch.no_grad():
+            self.output = self.net_g(self.lq)
+
+        if flip_seq:
+            output_1 = self.output[:, :n, :, :, :]
+            output_2 = self.output[:, n:, :, :, :].flip(1)
+            self.output = 0.5 * (output_1 + output_2)
+
+        if self.center_frame_only:
+            self.output = self.output[:, n // 2, :, :, :]
+
+        self.net_g.train()

basicsr/ops/dcn/__init__.py

+from .deform_conv import (DeformConv, DeformConvPack, ModulatedDeformConv, ModulatedDeformConvPack, deform_conv,
+                          modulated_deform_conv)
+
+__all__ = [
+    'DeformConv', 'DeformConvPack', 'ModulatedDeformConv', 'ModulatedDeformConvPack', 'deform_conv',
+    'modulated_deform_conv'
+]

basicsr/ops/dcn/deform_conv.py

+import math
+import os
+import torch
+from torch import nn as nn
+from torch.autograd import Function
+from torch.autograd.function import once_differentiable
+from torch.nn import functional as F
+from torch.nn.modules.utils import _pair, _single
+
+BASICSR_JIT = os.getenv('BASICSR_JIT')
+if BASICSR_JIT == 'True':
+    from torch.utils.cpp_extension import load
+    module_path = os.path.dirname(__file__)
+    deform_conv_ext = load(
+        'deform_conv',
+        sources=[
+            os.path.join(module_path, 'src', 'deform_conv_ext.cpp'),
+            os.path.join(module_path, 'src', 'deform_conv_cuda.cpp'),
+            os.path.join(module_path, 'src', 'deform_conv_cuda_kernel.cu'),
+        ],
+    )
+else:
+    try:
+        from . import deform_conv_ext
+    except ImportError:
+        pass
+        # avoid annoying print output
+        # print(f'Cannot import deform_conv_ext. Error: {error}. You may need to: \n '
+        #       '1. compile with BASICSR_EXT=True. or\n '
+        #       '2. set BASICSR_JIT=True during running')
+
+
+class DeformConvFunction(Function):
+
+    @staticmethod
+    def forward(ctx,
+                input,
+                offset,
+                weight,
+                stride=1,
+                padding=0,
+                dilation=1,
+                groups=1,
+                deformable_groups=1,
+                im2col_step=64):
+        if input is not None and input.dim() != 4:
+            raise ValueError(f'Expected 4D tensor as input, got {input.dim()}D tensor instead.')
+        ctx.stride = _pair(stride)
+        ctx.padding = _pair(padding)
+        ctx.dilation = _pair(dilation)
+        ctx.groups = groups
+        ctx.deformable_groups = deformable_groups
+        ctx.im2col_step = im2col_step
+
+        ctx.save_for_backward(input, offset, weight)
+
+        output = input.new_empty(DeformConvFunction._output_size(input, weight, ctx.padding, ctx.dilation, ctx.stride))
+
+        ctx.bufs_ = [input.new_empty(0), input.new_empty(0)]  # columns, ones
+
+        if not input.is_cuda:
+            raise NotImplementedError
+        else:
+            cur_im2col_step = min(ctx.im2col_step, input.shape[0])
+            assert (input.shape[0] % cur_im2col_step) == 0, 'im2col step must divide batchsize'
+            deform_conv_ext.deform_conv_forward(input, weight,
+                                                offset, output, ctx.bufs_[0], ctx.bufs_[1], weight.size(3),
+                                                weight.size(2), ctx.stride[1], ctx.stride[0], ctx.padding[1],
+                                                ctx.padding[0], ctx.dilation[1], ctx.dilation[0], ctx.groups,
+                                                ctx.deformable_groups, cur_im2col_step)
+        return output
+
+    @staticmethod
+    @once_differentiable
+    def backward(ctx, grad_output):
+        input, offset, weight = ctx.saved_tensors
+
+        grad_input = grad_offset = grad_weight = None
+
+        if not grad_output.is_cuda:
+            raise NotImplementedError
+        else:
+            cur_im2col_step = min(ctx.im2col_step, input.shape[0])
+            assert (input.shape[0] % cur_im2col_step) == 0, 'im2col step must divide batchsize'
+
+            if ctx.needs_input_grad[0] or ctx.needs_input_grad[1]:
+                grad_input = torch.zeros_like(input)
+                grad_offset = torch.zeros_like(offset)
+                deform_conv_ext.deform_conv_backward_input(input, offset, grad_output, grad_input,
+                                                           grad_offset, weight, ctx.bufs_[0], weight.size(3),
+                                                           weight.size(2), ctx.stride[1], ctx.stride[0], ctx.padding[1],
+                                                           ctx.padding[0], ctx.dilation[1], ctx.dilation[0], ctx.groups,
+                                                           ctx.deformable_groups, cur_im2col_step)
+
+            if ctx.needs_input_grad[2]:
+                grad_weight = torch.zeros_like(weight)
+                deform_conv_ext.deform_conv_backward_parameters(input, offset, grad_output, grad_weight,
+                                                                ctx.bufs_[0], ctx.bufs_[1], weight.size(3),
+                                                                weight.size(2), ctx.stride[1], ctx.stride[0],
+                                                                ctx.padding[1], ctx.padding[0], ctx.dilation[1],
+                                                                ctx.dilation[0], ctx.groups, ctx.deformable_groups, 1,
+                                                                cur_im2col_step)
+
+        return (grad_input, grad_offset, grad_weight, None, None, None, None, None)
+
+    @staticmethod
+    def _output_size(input, weight, padding, dilation, stride):
+        channels = weight.size(0)
+        output_size = (input.size(0), channels)
+        for d in range(input.dim() - 2):
+            in_size = input.size(d + 2)
+            pad = padding[d]
+            kernel = dilation[d] * (weight.size(d + 2) - 1) + 1
+            stride_ = stride[d]
+            output_size += ((in_size + (2 * pad) - kernel) // stride_ + 1, )
+        if not all(map(lambda s: s > 0, output_size)):
+            raise ValueError(f'convolution input is too small (output would be {"x".join(map(str, output_size))})')
+        return output_size
+
+
+class ModulatedDeformConvFunction(Function):
+
+    @staticmethod
+    def forward(ctx,
+                input,
+                offset,
+                mask,
+                weight,
+                bias=None,
+                stride=1,
+                padding=0,
+                dilation=1,
+                groups=1,
+                deformable_groups=1):
+        ctx.stride = stride
+        ctx.padding = padding
+        ctx.dilation = dilation
+        ctx.groups = groups
+        ctx.deformable_groups = deformable_groups
+        ctx.with_bias = bias is not None
+        if not ctx.with_bias:
+            bias = input.new_empty(1)  # fake tensor
+        if not input.is_cuda:
+            raise NotImplementedError
+        if weight.requires_grad or mask.requires_grad or offset.requires_grad or input.requires_grad:
+            ctx.save_for_backward(input, offset, mask, weight, bias)
+        output = input.new_empty(ModulatedDeformConvFunction._infer_shape(ctx, input, weight))
+        ctx._bufs = [input.new_empty(0), input.new_empty(0)]
+        deform_conv_ext.modulated_deform_conv_forward(input, weight, bias, ctx._bufs[0], offset, mask, output,
+                                                      ctx._bufs[1], weight.shape[2], weight.shape[3], ctx.stride,
+                                                      ctx.stride, ctx.padding, ctx.padding, ctx.dilation, ctx.dilation,
+                                                      ctx.groups, ctx.deformable_groups, ctx.with_bias)
+        return output
+
+    @staticmethod
+    @once_differentiable
+    def backward(ctx, grad_output):
+        if not grad_output.is_cuda:
+            raise NotImplementedError
+        input, offset, mask, weight, bias = ctx.saved_tensors
+        grad_input = torch.zeros_like(input)
+        grad_offset = torch.zeros_like(offset)
+        grad_mask = torch.zeros_like(mask)
+        grad_weight = torch.zeros_like(weight)
+        grad_bias = torch.zeros_like(bias)
+        deform_conv_ext.modulated_deform_conv_backward(input, weight, bias, ctx._bufs[0], offset, mask, ctx._bufs[1],
+                                                       grad_input, grad_weight, grad_bias, grad_offset, grad_mask,
+                                                       grad_output, weight.shape[2], weight.shape[3], ctx.stride,
+                                                       ctx.stride, ctx.padding, ctx.padding, ctx.dilation, ctx.dilation,
+                                                       ctx.groups, ctx.deformable_groups, ctx.with_bias)
+        if not ctx.with_bias:
+            grad_bias = None
+
+        return (grad_input, grad_offset, grad_mask, grad_weight, grad_bias, None, None, None, None, None)
+
+    @staticmethod
+    def _infer_shape(ctx, input, weight):
+        n = input.size(0)
+        channels_out = weight.size(0)
+        height, width = input.shape[2:4]
+        kernel_h, kernel_w = weight.shape[2:4]
+        height_out = (height + 2 * ctx.padding - (ctx.dilation * (kernel_h - 1) + 1)) // ctx.stride + 1
+        width_out = (width + 2 * ctx.padding - (ctx.dilation * (kernel_w - 1) + 1)) // ctx.stride + 1
+        return n, channels_out, height_out, width_out
+
+
+deform_conv = DeformConvFunction.apply
+modulated_deform_conv = ModulatedDeformConvFunction.apply
+
+
+class DeformConv(nn.Module):
+
+    def __init__(self,
+                 in_channels,
+                 out_channels,
+                 kernel_size,
+                 stride=1,
+                 padding=0,
+                 dilation=1,
+                 groups=1,
+                 deformable_groups=1,
+                 bias=False):
+        super(DeformConv, self).__init__()
+
+        assert not bias
+        assert in_channels % groups == 0, f'in_channels {in_channels} is not divisible by groups {groups}'
+        assert out_channels % groups == 0, f'out_channels {out_channels} is not divisible by groups {groups}'
+
+        self.in_channels = in_channels
+        self.out_channels = out_channels
+        self.kernel_size = _pair(kernel_size)
+        self.stride = _pair(stride)
+        self.padding = _pair(padding)
+        self.dilation = _pair(dilation)
+        self.groups = groups
+        self.deformable_groups = deformable_groups
+        # enable compatibility with nn.Conv2d
+        self.transposed = False
+        self.output_padding = _single(0)
+
+        self.weight = nn.Parameter(torch.Tensor(out_channels, in_channels // self.groups, *self.kernel_size))
+
+        self.reset_parameters()
+
+    def reset_parameters(self):
+        n = self.in_channels
+        for k in self.kernel_size:
+            n *= k
+        stdv = 1. / math.sqrt(n)
+        self.weight.data.uniform_(-stdv, stdv)
+
+    def forward(self, x, offset):
+        # To fix an assert error in deform_conv_cuda.cpp:128
+        # input image is smaller than kernel
+        input_pad = (x.size(2) < self.kernel_size[0] or x.size(3) < self.kernel_size[1])
+        if input_pad:
+            pad_h = max(self.kernel_size[0] - x.size(2), 0)
+            pad_w = max(self.kernel_size[1] - x.size(3), 0)
+            x = F.pad(x, (0, pad_w, 0, pad_h), 'constant', 0).contiguous()
+            offset = F.pad(offset, (0, pad_w, 0, pad_h), 'constant', 0).contiguous()
+        out = deform_conv(x, offset, self.weight, self.stride, self.padding, self.dilation, self.groups,
+                          self.deformable_groups)
+        if input_pad:
+            out = out[:, :, :out.size(2) - pad_h, :out.size(3) - pad_w].contiguous()
+        return out
+
+
+class DeformConvPack(DeformConv):
+    """A Deformable Conv Encapsulation that acts as normal Conv layers.
+
+    Args:
+        in_channels (int): Same as nn.Conv2d.
+        out_channels (int): Same as nn.Conv2d.
+        kernel_size (int or tuple[int]): Same as nn.Conv2d.
+        stride (int or tuple[int]): Same as nn.Conv2d.
+        padding (int or tuple[int]): Same as nn.Conv2d.
+        dilation (int or tuple[int]): Same as nn.Conv2d.
+        groups (int): Same as nn.Conv2d.
+        bias (bool or str): If specified as `auto`, it will be decided by the
+            norm_cfg. Bias will be set as True if norm_cfg is None, otherwise
+            False.
+    """
+
+    _version = 2
+
+    def __init__(self, *args, **kwargs):
+        super(DeformConvPack, self).__init__(*args, **kwargs)
+
+        self.conv_offset = nn.Conv2d(
+            self.in_channels,
+            self.deformable_groups * 2 * self.kernel_size[0] * self.kernel_size[1],
+            kernel_size=self.kernel_size,
+            stride=_pair(self.stride),
+            padding=_pair(self.padding),
+            dilation=_pair(self.dilation),
+            bias=True)
+        self.init_offset()
+
+    def init_offset(self):
+        self.conv_offset.weight.data.zero_()
+        self.conv_offset.bias.data.zero_()
+
+    def forward(self, x):
+        offset = self.conv_offset(x)
+        return deform_conv(x, offset, self.weight, self.stride, self.padding, self.dilation, self.groups,
+                           self.deformable_groups)
+
+
+class ModulatedDeformConv(nn.Module):
+
+    def __init__(self,
+                 in_channels,
+                 out_channels,
+                 kernel_size,
+                 stride=1,
+                 padding=0,
+                 dilation=1,
+                 groups=1,
+                 deformable_groups=1,
+                 bias=True):
+        super(ModulatedDeformConv, self).__init__()
+        self.in_channels = in_channels
+        self.out_channels = out_channels
+        self.kernel_size = _pair(kernel_size)
+        self.stride = stride
+        self.padding = padding
+        self.dilation = dilation
+        self.groups = groups
+        self.deformable_groups = deformable_groups
+        self.with_bias = bias
+        # enable compatibility with nn.Conv2d
+        self.transposed = False
+        self.output_padding = _single(0)
+
+        self.weight = nn.Parameter(torch.Tensor(out_channels, in_channels // groups, *self.kernel_size))
+        if bias:
+            self.bias = nn.Parameter(torch.Tensor(out_channels))
+        else:
+            self.register_parameter('bias', None)
+        self.init_weights()
+
+    def init_weights(self):
+        n = self.in_channels
+        for k in self.kernel_size:
+            n *= k
+        stdv = 1. / math.sqrt(n)
+        self.weight.data.uniform_(-stdv, stdv)
+        if self.bias is not None:
+            self.bias.data.zero_()
+
+    def forward(self, x, offset, mask):
+        return modulated_deform_conv(x, offset, mask, self.weight, self.bias, self.stride, self.padding, self.dilation,
+                                     self.groups, self.deformable_groups)
+
+
+class ModulatedDeformConvPack(ModulatedDeformConv):
+    """A ModulatedDeformable Conv Encapsulation that acts as normal Conv layers.
+
+    Args:
+        in_channels (int): Same as nn.Conv2d.
+        out_channels (int): Same as nn.Conv2d.
+        kernel_size (int or tuple[int]): Same as nn.Conv2d.
+        stride (int or tuple[int]): Same as nn.Conv2d.
+        padding (int or tuple[int]): Same as nn.Conv2d.
+        dilation (int or tuple[int]): Same as nn.Conv2d.
+        groups (int): Same as nn.Conv2d.
+        bias (bool or str): If specified as `auto`, it will be decided by the
+            norm_cfg. Bias will be set as True if norm_cfg is None, otherwise
+            False.
+    """
+
+    _version = 2
+
+    def __init__(self, *args, **kwargs):
+        super(ModulatedDeformConvPack, self).__init__(*args, **kwargs)
+
+        self.conv_offset = nn.Conv2d(
+            self.in_channels,
+            self.deformable_groups * 3 * self.kernel_size[0] * self.kernel_size[1],
+            kernel_size=self.kernel_size,
+            stride=_pair(self.stride),
+            padding=_pair(self.padding),
+            dilation=_pair(self.dilation),
+            bias=True)
+        self.init_weights()
+
+    def init_weights(self):
+        super(ModulatedDeformConvPack, self).init_weights()
+        if hasattr(self, 'conv_offset'):
+            self.conv_offset.weight.data.zero_()
+            self.conv_offset.bias.data.zero_()
+
+    def forward(self, x):
+        out = self.conv_offset(x)
+        o1, o2, mask = torch.chunk(out, 3, dim=1)
+        offset = torch.cat((o1, o2), dim=1)
+        mask = torch.sigmoid(mask)
+        return modulated_deform_conv(x, offset, mask, self.weight, self.bias, self.stride, self.padding, self.dilation,
+                                     self.groups, self.deformable_groups)

basicsr/ops/dcn/src/deform_conv_cuda.cpp

+// modify from
+// https://github.com/chengdazhi/Deformable-Convolution-V2-PyTorch/blob/mmdetection/mmdet/ops/dcn/src/deform_conv_cuda.c
+
+#include <torch/extension.h>
+#include <ATen/DeviceGuard.h>
+
+#include <cmath>
+#include <vector>
+
+void deformable_im2col(const at::Tensor data_im, const at::Tensor data_offset,
+                       const int channels, const int height, const int width,
+                       const int ksize_h, const int ksize_w, const int pad_h,
+                       const int pad_w, const int stride_h, const int stride_w,
+                       const int dilation_h, const int dilation_w,
+                       const int parallel_imgs, const int deformable_group,
+                       at::Tensor data_col);
+
+void deformable_col2im(const at::Tensor data_col, const at::Tensor data_offset,
+                       const int channels, const int height, const int width,
+                       const int ksize_h, const int ksize_w, const int pad_h,
+                       const int pad_w, const int stride_h, const int stride_w,
+                       const int dilation_h, const int dilation_w,
+                       const int parallel_imgs, const int deformable_group,
+                       at::Tensor grad_im);
+
+void deformable_col2im_coord(
+    const at::Tensor data_col, const at::Tensor data_im,
+    const at::Tensor data_offset, const int channels, const int height,
+    const int width, const int ksize_h, const int ksize_w, const int pad_h,
+    const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w, const int parallel_imgs,
+    const int deformable_group, at::Tensor grad_offset);
+
+void modulated_deformable_im2col_cuda(
+    const at::Tensor data_im, const at::Tensor data_offset,
+    const at::Tensor data_mask, const int batch_size, const int channels,
+    const int height_im, const int width_im, const int height_col,
+    const int width_col, const int kernel_h, const int kenerl_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w, const int deformable_group,
+    at::Tensor data_col);
+
+void modulated_deformable_col2im_cuda(
+    const at::Tensor data_col, const at::Tensor data_offset,
+    const at::Tensor data_mask, const int batch_size, const int channels,
+    const int height_im, const int width_im, const int height_col,
+    const int width_col, const int kernel_h, const int kenerl_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w, const int deformable_group,
+    at::Tensor grad_im);
+
+void modulated_deformable_col2im_coord_cuda(
+    const at::Tensor data_col, const at::Tensor data_im,
+    const at::Tensor data_offset, const at::Tensor data_mask,
+    const int batch_size, const int channels, const int height_im,
+    const int width_im, const int height_col, const int width_col,
+    const int kernel_h, const int kenerl_w, const int pad_h, const int pad_w,
+    const int stride_h, const int stride_w, const int dilation_h,
+    const int dilation_w, const int deformable_group, at::Tensor grad_offset,
+    at::Tensor grad_mask);
+
+void shape_check(at::Tensor input, at::Tensor offset, at::Tensor *gradOutput,
+                 at::Tensor weight, int kH, int kW, int dH, int dW, int padH,
+                 int padW, int dilationH, int dilationW, int group,
+                 int deformable_group) {
+  TORCH_CHECK(weight.ndimension() == 4,
+           "4D weight tensor (nOutputPlane,nInputPlane,kH,kW) expected, "
+           "but got: %s",
+           weight.ndimension());
+
+  TORCH_CHECK(weight.is_contiguous(), "weight tensor has to be contiguous");
+
+  TORCH_CHECK(kW > 0 && kH > 0,
+           "kernel size should be greater than zero, but got kH: %d kW: %d", kH,
+           kW);
+
+  TORCH_CHECK((weight.size(2) == kH && weight.size(3) == kW),
+           "kernel size should be consistent with weight, ",
+           "but got kH: %d kW: %d weight.size(2): %d, weight.size(3): %d", kH,
+           kW, weight.size(2), weight.size(3));
+
+  TORCH_CHECK(dW > 0 && dH > 0,
+           "stride should be greater than zero, but got dH: %d dW: %d", dH, dW);
+
+  TORCH_CHECK(
+      dilationW > 0 && dilationH > 0,
+      "dilation should be greater than 0, but got dilationH: %d dilationW: %d",
+      dilationH, dilationW);
+
+  int ndim = input.ndimension();
+  int dimf = 0;
+  int dimh = 1;
+  int dimw = 2;
+
+  if (ndim == 4) {
+    dimf++;
+    dimh++;
+    dimw++;
+  }
+
+  TORCH_CHECK(ndim == 3 || ndim == 4, "3D or 4D input tensor expected but got: %s",
+           ndim);
+
+  long nInputPlane = weight.size(1) * group;
+  long inputHeight = input.size(dimh);
+  long inputWidth = input.size(dimw);
+  long nOutputPlane = weight.size(0);
+  long outputHeight =
+      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;
+  long outputWidth =
+      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
+
+  TORCH_CHECK(nInputPlane % deformable_group == 0,
+           "input channels must divide deformable group size");
+
+  if (outputWidth < 1 || outputHeight < 1)
+    AT_ERROR(
+        "Given input size: (%ld x %ld x %ld). "
+        "Calculated output size: (%ld x %ld x %ld). Output size is too small",
+        nInputPlane, inputHeight, inputWidth, nOutputPlane, outputHeight,
+        outputWidth);
+
+  TORCH_CHECK(input.size(1) == nInputPlane,
+           "invalid number of input planes, expected: %d, but got: %d",
+           nInputPlane, input.size(1));
+
+  TORCH_CHECK((inputHeight >= kH && inputWidth >= kW),
+           "input image is smaller than kernel");
+
+  TORCH_CHECK((offset.size(2) == outputHeight && offset.size(3) == outputWidth),
+           "invalid spatial size of offset, expected height: %d width: %d, but "
+           "got height: %d width: %d",
+           outputHeight, outputWidth, offset.size(2), offset.size(3));
+
+  TORCH_CHECK((offset.size(1) == deformable_group * 2 * kH * kW),
+           "invalid number of channels of offset");
+
+  if (gradOutput != NULL) {
+    TORCH_CHECK(gradOutput->size(dimf) == nOutputPlane,
+             "invalid number of gradOutput planes, expected: %d, but got: %d",
+             nOutputPlane, gradOutput->size(dimf));
+
+    TORCH_CHECK((gradOutput->size(dimh) == outputHeight &&
+              gradOutput->size(dimw) == outputWidth),
+             "invalid size of gradOutput, expected height: %d width: %d , but "
+             "got height: %d width: %d",
+             outputHeight, outputWidth, gradOutput->size(dimh),
+             gradOutput->size(dimw));
+  }
+}
+
+int deform_conv_forward_cuda(at::Tensor input, at::Tensor weight,
+                             at::Tensor offset, at::Tensor output,
+                             at::Tensor columns, at::Tensor ones, int kW,
+                             int kH, int dW, int dH, int padW, int padH,
+                             int dilationW, int dilationH, int group,
+                             int deformable_group, int im2col_step) {
+  // todo: resize columns to include im2col: done
+  // todo: add im2col_step as input
+  // todo: add new output buffer and transpose it to output (or directly
+  // transpose output) todo: possibly change data indexing because of
+  // parallel_imgs
+
+  shape_check(input, offset, NULL, weight, kH, kW, dH, dW, padH, padW,
+              dilationH, dilationW, group, deformable_group);
+  at::DeviceGuard guard(input.device());
+
+  input = input.contiguous();
+  offset = offset.contiguous();
+  weight = weight.contiguous();
+
+  int batch = 1;
+  if (input.ndimension() == 3) {
+    // Force batch
+    batch = 0;
+    input.unsqueeze_(0);
+    offset.unsqueeze_(0);
+  }
+
+  // todo: assert batchsize dividable by im2col_step
+
+  long batchSize = input.size(0);
+  long nInputPlane = input.size(1);
+  long inputHeight = input.size(2);
+  long inputWidth = input.size(3);
+
+  long nOutputPlane = weight.size(0);
+
+  long outputWidth =
+      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
+  long outputHeight =
+      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;
+
+  TORCH_CHECK((offset.size(0) == batchSize), "invalid batch size of offset");
+
+  output = output.view({batchSize / im2col_step, im2col_step, nOutputPlane,
+                        outputHeight, outputWidth});
+  columns = at::zeros(
+      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
+      input.options());
+
+  if (ones.ndimension() != 2 ||
+      ones.size(0) * ones.size(1) < outputHeight * outputWidth) {
+    ones = at::ones({outputHeight, outputWidth}, input.options());
+  }
+
+  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
+                      inputHeight, inputWidth});
+  offset =
+      offset.view({batchSize / im2col_step, im2col_step,
+                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  at::Tensor output_buffer =
+      at::zeros({batchSize / im2col_step, nOutputPlane,
+                 im2col_step * outputHeight, outputWidth},
+                output.options());
+
+  output_buffer = output_buffer.view(
+      {output_buffer.size(0), group, output_buffer.size(1) / group,
+       output_buffer.size(2), output_buffer.size(3)});
+
+  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
+    deformable_im2col(input[elt], offset[elt], nInputPlane, inputHeight,
+                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
+                      dilationW, im2col_step, deformable_group, columns);
+
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+    weight = weight.view({group, weight.size(0) / group, weight.size(1),
+                          weight.size(2), weight.size(3)});
+
+    for (int g = 0; g < group; g++) {
+      output_buffer[elt][g] = output_buffer[elt][g]
+                                  .flatten(1)
+                                  .addmm_(weight[g].flatten(1), columns[g])
+                                  .view_as(output_buffer[elt][g]);
+    }
+  }
+
+  output_buffer = output_buffer.view(
+      {output_buffer.size(0), output_buffer.size(1) * output_buffer.size(2),
+       output_buffer.size(3), output_buffer.size(4)});
+
+  output_buffer = output_buffer.view({batchSize / im2col_step, nOutputPlane,
+                                      im2col_step, outputHeight, outputWidth});
+  output_buffer.transpose_(1, 2);
+  output.copy_(output_buffer);
+  output = output.view({batchSize, nOutputPlane, outputHeight, outputWidth});
+
+  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
+  offset = offset.view(
+      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  if (batch == 0) {
+    output = output.view({nOutputPlane, outputHeight, outputWidth});
+    input = input.view({nInputPlane, inputHeight, inputWidth});
+    offset = offset.view({offset.size(1), offset.size(2), offset.size(3)});
+  }
+
+  return 1;
+}
+
+int deform_conv_backward_input_cuda(at::Tensor input, at::Tensor offset,
+                                    at::Tensor gradOutput, at::Tensor gradInput,
+                                    at::Tensor gradOffset, at::Tensor weight,
+                                    at::Tensor columns, int kW, int kH, int dW,
+                                    int dH, int padW, int padH, int dilationW,
+                                    int dilationH, int group,
+                                    int deformable_group, int im2col_step) {
+  shape_check(input, offset, &gradOutput, weight, kH, kW, dH, dW, padH, padW,
+              dilationH, dilationW, group, deformable_group);
+  at::DeviceGuard guard(input.device());
+
+  input = input.contiguous();
+  offset = offset.contiguous();
+  gradOutput = gradOutput.contiguous();
+  weight = weight.contiguous();
+
+  int batch = 1;
+
+  if (input.ndimension() == 3) {
+    // Force batch
+    batch = 0;
+    input = input.view({1, input.size(0), input.size(1), input.size(2)});
+    offset = offset.view({1, offset.size(0), offset.size(1), offset.size(2)});
+    gradOutput = gradOutput.view(
+        {1, gradOutput.size(0), gradOutput.size(1), gradOutput.size(2)});
+  }
+
+  long batchSize = input.size(0);
+  long nInputPlane = input.size(1);
+  long inputHeight = input.size(2);
+  long inputWidth = input.size(3);
+
+  long nOutputPlane = weight.size(0);
+
+  long outputWidth =
+      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
+  long outputHeight =
+      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;
+
+  TORCH_CHECK((offset.size(0) == batchSize), 3, "invalid batch size of offset");
+  gradInput = gradInput.view({batchSize, nInputPlane, inputHeight, inputWidth});
+  columns = at::zeros(
+      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
+      input.options());
+
+  // change order of grad output
+  gradOutput = gradOutput.view({batchSize / im2col_step, im2col_step,
+                                nOutputPlane, outputHeight, outputWidth});
+  gradOutput.transpose_(1, 2);
+
+  gradInput = gradInput.view({batchSize / im2col_step, im2col_step, nInputPlane,
+                              inputHeight, inputWidth});
+  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
+                      inputHeight, inputWidth});
+  gradOffset = gradOffset.view({batchSize / im2col_step, im2col_step,
+                                deformable_group * 2 * kH * kW, outputHeight,
+                                outputWidth});
+  offset =
+      offset.view({batchSize / im2col_step, im2col_step,
+                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
+    // divide into groups
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+    weight = weight.view({group, weight.size(0) / group, weight.size(1),
+                          weight.size(2), weight.size(3)});
+    gradOutput = gradOutput.view(
+        {gradOutput.size(0), group, gradOutput.size(1) / group,
+         gradOutput.size(2), gradOutput.size(3), gradOutput.size(4)});
+
+    for (int g = 0; g < group; g++) {
+      columns[g] = columns[g].addmm_(weight[g].flatten(1).transpose(0, 1),
+                                     gradOutput[elt][g].flatten(1), 0.0f, 1.0f);
+    }
+
+    columns =
+        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
+    gradOutput = gradOutput.view(
+        {gradOutput.size(0), gradOutput.size(1) * gradOutput.size(2),
+         gradOutput.size(3), gradOutput.size(4), gradOutput.size(5)});
+
+    deformable_col2im_coord(columns, input[elt], offset[elt], nInputPlane,
+                            inputHeight, inputWidth, kH, kW, padH, padW, dH, dW,
+                            dilationH, dilationW, im2col_step, deformable_group,
+                            gradOffset[elt]);
+
+    deformable_col2im(columns, offset[elt], nInputPlane, inputHeight,
+                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
+                      dilationW, im2col_step, deformable_group, gradInput[elt]);
+  }
+
+  gradOutput.transpose_(1, 2);
+  gradOutput =
+      gradOutput.view({batchSize, nOutputPlane, outputHeight, outputWidth});
+
+  gradInput = gradInput.view({batchSize, nInputPlane, inputHeight, inputWidth});
+  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
+  gradOffset = gradOffset.view(
+      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+  offset = offset.view(
+      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  if (batch == 0) {
+    gradOutput = gradOutput.view({nOutputPlane, outputHeight, outputWidth});
+    input = input.view({nInputPlane, inputHeight, inputWidth});
+    gradInput = gradInput.view({nInputPlane, inputHeight, inputWidth});
+    offset = offset.view({offset.size(1), offset.size(2), offset.size(3)});
+    gradOffset =
+        gradOffset.view({offset.size(1), offset.size(2), offset.size(3)});
+  }
+
+  return 1;
+}
+
+int deform_conv_backward_parameters_cuda(
+    at::Tensor input, at::Tensor offset, at::Tensor gradOutput,
+    at::Tensor gradWeight,  // at::Tensor gradBias,
+    at::Tensor columns, at::Tensor ones, int kW, int kH, int dW, int dH,
+    int padW, int padH, int dilationW, int dilationH, int group,
+    int deformable_group, float scale, int im2col_step) {
+  // todo: transpose and reshape outGrad
+  // todo: reshape columns
+  // todo: add im2col_step as input
+
+  shape_check(input, offset, &gradOutput, gradWeight, kH, kW, dH, dW, padH,
+              padW, dilationH, dilationW, group, deformable_group);
+  at::DeviceGuard guard(input.device());
+
+  input = input.contiguous();
+  offset = offset.contiguous();
+  gradOutput = gradOutput.contiguous();
+
+  int batch = 1;
+
+  if (input.ndimension() == 3) {
+    // Force batch
+    batch = 0;
+    input = input.view(
+        at::IntList({1, input.size(0), input.size(1), input.size(2)}));
+    gradOutput = gradOutput.view(
+        {1, gradOutput.size(0), gradOutput.size(1), gradOutput.size(2)});
+  }
+
+  long batchSize = input.size(0);
+  long nInputPlane = input.size(1);
+  long inputHeight = input.size(2);
+  long inputWidth = input.size(3);
+
+  long nOutputPlane = gradWeight.size(0);
+
+  long outputWidth =
+      (inputWidth + 2 * padW - (dilationW * (kW - 1) + 1)) / dW + 1;
+  long outputHeight =
+      (inputHeight + 2 * padH - (dilationH * (kH - 1) + 1)) / dH + 1;
+
+  TORCH_CHECK((offset.size(0) == batchSize), "invalid batch size of offset");
+
+  columns = at::zeros(
+      {nInputPlane * kW * kH, im2col_step * outputHeight * outputWidth},
+      input.options());
+
+  gradOutput = gradOutput.view({batchSize / im2col_step, im2col_step,
+                                nOutputPlane, outputHeight, outputWidth});
+  gradOutput.transpose_(1, 2);
+
+  at::Tensor gradOutputBuffer = at::zeros_like(gradOutput);
+  gradOutputBuffer =
+      gradOutputBuffer.view({batchSize / im2col_step, nOutputPlane, im2col_step,
+                             outputHeight, outputWidth});
+  gradOutputBuffer.copy_(gradOutput);
+  gradOutputBuffer =
+      gradOutputBuffer.view({batchSize / im2col_step, nOutputPlane,
+                             im2col_step * outputHeight, outputWidth});
+
+  gradOutput.transpose_(1, 2);
+  gradOutput =
+      gradOutput.view({batchSize, nOutputPlane, outputHeight, outputWidth});
+
+  input = input.view({batchSize / im2col_step, im2col_step, nInputPlane,
+                      inputHeight, inputWidth});
+  offset =
+      offset.view({batchSize / im2col_step, im2col_step,
+                   deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  for (int elt = 0; elt < batchSize / im2col_step; elt++) {
+    deformable_im2col(input[elt], offset[elt], nInputPlane, inputHeight,
+                      inputWidth, kH, kW, padH, padW, dH, dW, dilationH,
+                      dilationW, im2col_step, deformable_group, columns);
+
+    // divide into group
+    gradOutputBuffer = gradOutputBuffer.view(
+        {gradOutputBuffer.size(0), group, gradOutputBuffer.size(1) / group,
+         gradOutputBuffer.size(2), gradOutputBuffer.size(3)});
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+    gradWeight =
+        gradWeight.view({group, gradWeight.size(0) / group, gradWeight.size(1),
+                         gradWeight.size(2), gradWeight.size(3)});
+
+    for (int g = 0; g < group; g++) {
+      gradWeight[g] = gradWeight[g]
+                          .flatten(1)
+                          .addmm_(gradOutputBuffer[elt][g].flatten(1),
+                                  columns[g].transpose(1, 0), 1.0, scale)
+                          .view_as(gradWeight[g]);
+    }
+    gradOutputBuffer = gradOutputBuffer.view(
+        {gradOutputBuffer.size(0),
+         gradOutputBuffer.size(1) * gradOutputBuffer.size(2),
+         gradOutputBuffer.size(3), gradOutputBuffer.size(4)});
+    columns =
+        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
+    gradWeight = gradWeight.view({gradWeight.size(0) * gradWeight.size(1),
+                                  gradWeight.size(2), gradWeight.size(3),
+                                  gradWeight.size(4)});
+  }
+
+  input = input.view({batchSize, nInputPlane, inputHeight, inputWidth});
+  offset = offset.view(
+      {batchSize, deformable_group * 2 * kH * kW, outputHeight, outputWidth});
+
+  if (batch == 0) {
+    gradOutput = gradOutput.view({nOutputPlane, outputHeight, outputWidth});
+    input = input.view({nInputPlane, inputHeight, inputWidth});
+  }
+
+  return 1;
+}
+
+void modulated_deform_conv_cuda_forward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor output, at::Tensor columns,
+    int kernel_h, int kernel_w, const int stride_h, const int stride_w,
+    const int pad_h, const int pad_w, const int dilation_h,
+    const int dilation_w, const int group, const int deformable_group,
+    const bool with_bias) {
+  TORCH_CHECK(input.is_contiguous(), "input tensor has to be contiguous");
+  TORCH_CHECK(weight.is_contiguous(), "weight tensor has to be contiguous");
+  at::DeviceGuard guard(input.device());
+
+  const int batch = input.size(0);
+  const int channels = input.size(1);
+  const int height = input.size(2);
+  const int width = input.size(3);
+
+  const int channels_out = weight.size(0);
+  const int channels_kernel = weight.size(1);
+  const int kernel_h_ = weight.size(2);
+  const int kernel_w_ = weight.size(3);
+
+  if (kernel_h_ != kernel_h || kernel_w_ != kernel_w)
+    AT_ERROR("Input shape and kernel shape won't match: (%d x %d vs %d x %d).",
+             kernel_h_, kernel_w, kernel_h_, kernel_w_);
+  if (channels != channels_kernel * group)
+    AT_ERROR("Input shape and kernel channels won't match: (%d vs %d).",
+             channels, channels_kernel * group);
+
+  const int height_out =
+      (height + 2 * pad_h - (dilation_h * (kernel_h - 1) + 1)) / stride_h + 1;
+  const int width_out =
+      (width + 2 * pad_w - (dilation_w * (kernel_w - 1) + 1)) / stride_w + 1;
+
+  if (ones.ndimension() != 2 ||
+      ones.size(0) * ones.size(1) < height_out * width_out) {
+    // Resize plane and fill with ones...
+    ones = at::ones({height_out, width_out}, input.options());
+  }
+
+  // resize output
+  output = output.view({batch, channels_out, height_out, width_out}).zero_();
+  // resize temporary columns
+  columns =
+      at::zeros({channels * kernel_h * kernel_w, 1 * height_out * width_out},
+                input.options());
+
+  output = output.view({output.size(0), group, output.size(1) / group,
+                        output.size(2), output.size(3)});
+
+  for (int b = 0; b < batch; b++) {
+    modulated_deformable_im2col_cuda(
+        input[b], offset[b], mask[b], 1, channels, height, width, height_out,
+        width_out, kernel_h, kernel_w, pad_h, pad_w, stride_h, stride_w,
+        dilation_h, dilation_w, deformable_group, columns);
+
+    // divide into group
+    weight = weight.view({group, weight.size(0) / group, weight.size(1),
+                          weight.size(2), weight.size(3)});
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+
+    for (int g = 0; g < group; g++) {
+      output[b][g] = output[b][g]
+                         .flatten(1)
+                         .addmm_(weight[g].flatten(1), columns[g])
+                         .view_as(output[b][g]);
+    }
+
+    weight = weight.view({weight.size(0) * weight.size(1), weight.size(2),
+                          weight.size(3), weight.size(4)});
+    columns =
+        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
+  }
+
+  output = output.view({output.size(0), output.size(1) * output.size(2),
+                        output.size(3), output.size(4)});
+
+  if (with_bias) {
+    output += bias.view({1, bias.size(0), 1, 1});
+  }
+}
+
+void modulated_deform_conv_cuda_backward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor columns,
+    at::Tensor grad_input, at::Tensor grad_weight, at::Tensor grad_bias,
+    at::Tensor grad_offset, at::Tensor grad_mask, at::Tensor grad_output,
+    int kernel_h, int kernel_w, int stride_h, int stride_w, int pad_h,
+    int pad_w, int dilation_h, int dilation_w, int group, int deformable_group,
+    const bool with_bias) {
+  TORCH_CHECK(input.is_contiguous(), "input tensor has to be contiguous");
+  TORCH_CHECK(weight.is_contiguous(), "weight tensor has to be contiguous");
+  at::DeviceGuard guard(input.device());
+
+  const int batch = input.size(0);
+  const int channels = input.size(1);
+  const int height = input.size(2);
+  const int width = input.size(3);
+
+  const int channels_kernel = weight.size(1);
+  const int kernel_h_ = weight.size(2);
+  const int kernel_w_ = weight.size(3);
+  if (kernel_h_ != kernel_h || kernel_w_ != kernel_w)
+    AT_ERROR("Input shape and kernel shape won't match: (%d x %d vs %d x %d).",
+             kernel_h_, kernel_w, kernel_h_, kernel_w_);
+  if (channels != channels_kernel * group)
+    AT_ERROR("Input shape and kernel channels won't match: (%d vs %d).",
+             channels, channels_kernel * group);
+
+  const int height_out =
+      (height + 2 * pad_h - (dilation_h * (kernel_h - 1) + 1)) / stride_h + 1;
+  const int width_out =
+      (width + 2 * pad_w - (dilation_w * (kernel_w - 1) + 1)) / stride_w + 1;
+
+  if (ones.ndimension() != 2 ||
+      ones.size(0) * ones.size(1) < height_out * width_out) {
+    // Resize plane and fill with ones...
+    ones = at::ones({height_out, width_out}, input.options());
+  }
+
+  grad_input = grad_input.view({batch, channels, height, width});
+  columns = at::zeros({channels * kernel_h * kernel_w, height_out * width_out},
+                      input.options());
+
+  grad_output =
+      grad_output.view({grad_output.size(0), group, grad_output.size(1) / group,
+                        grad_output.size(2), grad_output.size(3)});
+
+  for (int b = 0; b < batch; b++) {
+    // divide int group
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+    weight = weight.view({group, weight.size(0) / group, weight.size(1),
+                          weight.size(2), weight.size(3)});
+
+    for (int g = 0; g < group; g++) {
+      columns[g].addmm_(weight[g].flatten(1).transpose(0, 1),
+                        grad_output[b][g].flatten(1), 0.0f, 1.0f);
+    }
+
+    columns =
+        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
+    weight = weight.view({weight.size(0) * weight.size(1), weight.size(2),
+                          weight.size(3), weight.size(4)});
+
+    // gradient w.r.t. input coordinate data
+    modulated_deformable_col2im_coord_cuda(
+        columns, input[b], offset[b], mask[b], 1, channels, height, width,
+        height_out, width_out, kernel_h, kernel_w, pad_h, pad_w, stride_h,
+        stride_w, dilation_h, dilation_w, deformable_group, grad_offset[b],
+        grad_mask[b]);
+    // gradient w.r.t. input data
+    modulated_deformable_col2im_cuda(
+        columns, offset[b], mask[b], 1, channels, height, width, height_out,
+        width_out, kernel_h, kernel_w, pad_h, pad_w, stride_h, stride_w,
+        dilation_h, dilation_w, deformable_group, grad_input[b]);
+
+    // gradient w.r.t. weight, dWeight should accumulate across the batch and
+    // group
+    modulated_deformable_im2col_cuda(
+        input[b], offset[b], mask[b], 1, channels, height, width, height_out,
+        width_out, kernel_h, kernel_w, pad_h, pad_w, stride_h, stride_w,
+        dilation_h, dilation_w, deformable_group, columns);
+
+    columns = columns.view({group, columns.size(0) / group, columns.size(1)});
+    grad_weight = grad_weight.view({group, grad_weight.size(0) / group,
+                                    grad_weight.size(1), grad_weight.size(2),
+                                    grad_weight.size(3)});
+    if (with_bias)
+      grad_bias = grad_bias.view({group, grad_bias.size(0) / group});
+
+    for (int g = 0; g < group; g++) {
+      grad_weight[g] =
+          grad_weight[g]
+              .flatten(1)
+              .addmm_(grad_output[b][g].flatten(1), columns[g].transpose(0, 1))
+              .view_as(grad_weight[g]);
+      if (with_bias) {
+        grad_bias[g] =
+            grad_bias[g]
+                .view({-1, 1})
+                .addmm_(grad_output[b][g].flatten(1), ones.view({-1, 1}))
+                .view(-1);
+      }
+    }
+
+    columns =
+        columns.view({columns.size(0) * columns.size(1), columns.size(2)});
+    grad_weight = grad_weight.view({grad_weight.size(0) * grad_weight.size(1),
+                                    grad_weight.size(2), grad_weight.size(3),
+                                    grad_weight.size(4)});
+    if (with_bias)
+      grad_bias = grad_bias.view({grad_bias.size(0) * grad_bias.size(1)});
+  }
+  grad_output = grad_output.view({grad_output.size(0) * grad_output.size(1),
+                                  grad_output.size(2), grad_output.size(3),
+                                  grad_output.size(4)});
+}

basicsr/ops/dcn/src/deform_conv_cuda_kernel.cu

+/*!
+ ******************* BEGIN Caffe Copyright Notice and Disclaimer ****************
+ *
+ * COPYRIGHT
+ *
+ * All contributions by the University of California:
+ * Copyright (c) 2014-2017 The Regents of the University of California (Regents)
+ * All rights reserved.
+ *
+ * All other contributions:
+ * Copyright (c) 2014-2017, the respective contributors
+ * All rights reserved.
+ *
+ * Caffe uses a shared copyright model: each contributor holds copyright over
+ * their contributions to Caffe. The project versioning records all such
+ * contribution and copyright details. If a contributor wants to further mark
+ * their specific copyright on a particular contribution, they should indicate
+ * their copyright solely in the commit message of the change when it is
+ * committed.
+ *
+ * LICENSE
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * CONTRIBUTION AGREEMENT
+ *
+ * By contributing to the BVLC/caffe repository through pull-request, comment,
+ * or otherwise, the contributor releases their content to the
+ * license and copyright terms herein.
+ *
+ ***************** END Caffe Copyright Notice and Disclaimer ********************
+ *
+ * Copyright (c) 2018 Microsoft
+ * Licensed under The MIT License [see LICENSE for details]
+ * \file modulated_deformable_im2col.cuh
+ * \brief Function definitions of converting an image to
+ * column matrix based on kernel, padding, dilation, and offset.
+ * These functions are mainly used in deformable convolution operators.
+ * \ref: https://arxiv.org/abs/1703.06211
+ * \author Yuwen Xiong, Haozhi Qi, Jifeng Dai, Xizhou Zhu, Han Hu, Dazhi Cheng
+ */
+
+// modified from https://github.com/chengdazhi/Deformable-Convolution-V2-PyTorch/blob/mmdetection/mmdet/ops/dcn/src/deform_conv_cuda_kernel.cu
+
+#include <ATen/ATen.h>
+#include <ATen/cuda/CUDAContext.h>
+#include <THC/THCAtomics.cuh>
+#include <stdio.h>
+#include <math.h>
+#include <float.h>
+
+using namespace at;
+
+#define CUDA_KERNEL_LOOP(i, n)                                 \
+  for (int i = blockIdx.x * blockDim.x + threadIdx.x; i < (n); \
+       i += blockDim.x * gridDim.x)
+
+const int CUDA_NUM_THREADS = 1024;
+const int kMaxGridNum = 65535;
+
+inline int GET_BLOCKS(const int N)
+{
+  return std::min(kMaxGridNum, (N + CUDA_NUM_THREADS - 1) / CUDA_NUM_THREADS);
+}
+
+template <typename scalar_t>
+__device__ scalar_t deformable_im2col_bilinear(const scalar_t *bottom_data, const int data_width,
+                                               const int height, const int width, scalar_t h, scalar_t w)
+{
+
+  int h_low = floor(h);
+  int w_low = floor(w);
+  int h_high = h_low + 1;
+  int w_high = w_low + 1;
+
+  scalar_t lh = h - h_low;
+  scalar_t lw = w - w_low;
+  scalar_t hh = 1 - lh, hw = 1 - lw;
+
+  scalar_t v1 = 0;
+  if (h_low >= 0 && w_low >= 0)
+    v1 = bottom_data[h_low * data_width + w_low];
+  scalar_t v2 = 0;
+  if (h_low >= 0 && w_high <= width - 1)
+    v2 = bottom_data[h_low * data_width + w_high];
+  scalar_t v3 = 0;
+  if (h_high <= height - 1 && w_low >= 0)
+    v3 = bottom_data[h_high * data_width + w_low];
+  scalar_t v4 = 0;
+  if (h_high <= height - 1 && w_high <= width - 1)
+    v4 = bottom_data[h_high * data_width + w_high];
+
+  scalar_t w1 = hh * hw, w2 = hh * lw, w3 = lh * hw, w4 = lh * lw;
+
+  scalar_t val = (w1 * v1 + w2 * v2 + w3 * v3 + w4 * v4);
+  return val;
+}
+
+template <typename scalar_t>
+__device__ scalar_t get_gradient_weight(scalar_t argmax_h, scalar_t argmax_w,
+                                        const int h, const int w, const int height, const int width)
+{
+
+  if (argmax_h <= -1 || argmax_h >= height || argmax_w <= -1 || argmax_w >= width)
+  {
+    //empty
+    return 0;
+  }
+
+  int argmax_h_low = floor(argmax_h);
+  int argmax_w_low = floor(argmax_w);
+  int argmax_h_high = argmax_h_low + 1;
+  int argmax_w_high = argmax_w_low + 1;
+
+  scalar_t weight = 0;
+  if (h == argmax_h_low && w == argmax_w_low)
+    weight = (h + 1 - argmax_h) * (w + 1 - argmax_w);
+  if (h == argmax_h_low && w == argmax_w_high)
+    weight = (h + 1 - argmax_h) * (argmax_w + 1 - w);
+  if (h == argmax_h_high && w == argmax_w_low)
+    weight = (argmax_h + 1 - h) * (w + 1 - argmax_w);
+  if (h == argmax_h_high && w == argmax_w_high)
+    weight = (argmax_h + 1 - h) * (argmax_w + 1 - w);
+  return weight;
+}
+
+template <typename scalar_t>
+__device__ scalar_t get_coordinate_weight(scalar_t argmax_h, scalar_t argmax_w,
+                                          const int height, const int width, const scalar_t *im_data,
+                                          const int data_width, const int bp_dir)
+{
+
+  if (argmax_h <= -1 || argmax_h >= height || argmax_w <= -1 || argmax_w >= width)
+  {
+    //empty
+    return 0;
+  }
+
+  int argmax_h_low = floor(argmax_h);
+  int argmax_w_low = floor(argmax_w);
+  int argmax_h_high = argmax_h_low + 1;
+  int argmax_w_high = argmax_w_low + 1;
+
+  scalar_t weight = 0;
+
+  if (bp_dir == 0)
+  {
+    if (argmax_h_low >= 0 && argmax_w_low >= 0)
+      weight += -1 * (argmax_w_low + 1 - argmax_w) * im_data[argmax_h_low * data_width + argmax_w_low];
+    if (argmax_h_low >= 0 && argmax_w_high <= width - 1)
+      weight += -1 * (argmax_w - argmax_w_low) * im_data[argmax_h_low * data_width + argmax_w_high];
+    if (argmax_h_high <= height - 1 && argmax_w_low >= 0)
+      weight += (argmax_w_low + 1 - argmax_w) * im_data[argmax_h_high * data_width + argmax_w_low];
+    if (argmax_h_high <= height - 1 && argmax_w_high <= width - 1)
+      weight += (argmax_w - argmax_w_low) * im_data[argmax_h_high * data_width + argmax_w_high];
+  }
+  else if (bp_dir == 1)
+  {
+    if (argmax_h_low >= 0 && argmax_w_low >= 0)
+      weight += -1 * (argmax_h_low + 1 - argmax_h) * im_data[argmax_h_low * data_width + argmax_w_low];
+    if (argmax_h_low >= 0 && argmax_w_high <= width - 1)
+      weight += (argmax_h_low + 1 - argmax_h) * im_data[argmax_h_low * data_width + argmax_w_high];
+    if (argmax_h_high <= height - 1 && argmax_w_low >= 0)
+      weight += -1 * (argmax_h - argmax_h_low) * im_data[argmax_h_high * data_width + argmax_w_low];
+    if (argmax_h_high <= height - 1 && argmax_w_high <= width - 1)
+      weight += (argmax_h - argmax_h_low) * im_data[argmax_h_high * data_width + argmax_w_high];
+  }
+
+  return weight;
+}
+
+template <typename scalar_t>
+__global__ void deformable_im2col_gpu_kernel(const int n, const scalar_t *data_im, const scalar_t *data_offset,
+                                             const int height, const int width, const int kernel_h, const int kernel_w,
+                                             const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+                                             const int dilation_h, const int dilation_w, const int channel_per_deformable_group,
+                                             const int batch_size, const int num_channels, const int deformable_group,
+                                             const int height_col, const int width_col,
+                                             scalar_t *data_col)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    // index index of output matrix
+    const int w_col = index % width_col;
+    const int h_col = (index / width_col) % height_col;
+    const int b_col = (index / width_col / height_col) % batch_size;
+    const int c_im = (index / width_col / height_col) / batch_size;
+    const int c_col = c_im * kernel_h * kernel_w;
+
+    // compute deformable group index
+    const int deformable_group_index = c_im / channel_per_deformable_group;
+
+    const int h_in = h_col * stride_h - pad_h;
+    const int w_in = w_col * stride_w - pad_w;
+    scalar_t *data_col_ptr = data_col + ((c_col * batch_size + b_col) * height_col + h_col) * width_col + w_col;
+    //const scalar_t* data_im_ptr = data_im + ((b_col * num_channels + c_im) * height + h_in) * width + w_in;
+    const scalar_t *data_im_ptr = data_im + (b_col * num_channels + c_im) * height * width;
+    const scalar_t *data_offset_ptr = data_offset + (b_col * deformable_group + deformable_group_index) * 2 * kernel_h * kernel_w * height_col * width_col;
+
+    for (int i = 0; i < kernel_h; ++i)
+    {
+      for (int j = 0; j < kernel_w; ++j)
+      {
+        const int data_offset_h_ptr = ((2 * (i * kernel_w + j)) * height_col + h_col) * width_col + w_col;
+        const int data_offset_w_ptr = ((2 * (i * kernel_w + j) + 1) * height_col + h_col) * width_col + w_col;
+        const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+        const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+        scalar_t val = static_cast<scalar_t>(0);
+        const scalar_t h_im = h_in + i * dilation_h + offset_h;
+        const scalar_t w_im = w_in + j * dilation_w + offset_w;
+        if (h_im > -1 && w_im > -1 && h_im < height && w_im < width)
+        {
+          //const scalar_t map_h = i * dilation_h + offset_h;
+          //const scalar_t map_w = j * dilation_w + offset_w;
+          //const int cur_height = height - h_in;
+          //const int cur_width = width - w_in;
+          //val = deformable_im2col_bilinear(data_im_ptr, width, cur_height, cur_width, map_h, map_w);
+          val = deformable_im2col_bilinear(data_im_ptr, width, height, width, h_im, w_im);
+        }
+        *data_col_ptr = val;
+        data_col_ptr += batch_size * height_col * width_col;
+      }
+    }
+  }
+}
+
+void deformable_im2col(
+    const at::Tensor data_im, const at::Tensor data_offset, const int channels,
+    const int height, const int width, const int ksize_h, const int ksize_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w, const int parallel_imgs,
+    const int deformable_group, at::Tensor data_col)
+{
+  // num_axes should be smaller than block size
+  // todo: check parallel_imgs is correctly passed in
+  int height_col = (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
+  int width_col = (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
+  int num_kernels = channels * height_col * width_col * parallel_imgs;
+  int channel_per_deformable_group = channels / deformable_group;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_im.scalar_type(), "deformable_im2col_gpu", ([&] {
+        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+
+        deformable_im2col_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_im_, data_offset_, height, width, ksize_h, ksize_w,
+            pad_h, pad_w, stride_h, stride_w, dilation_h, dilation_w,
+            channel_per_deformable_group, parallel_imgs, channels, deformable_group,
+            height_col, width_col, data_col_);
+      }));
+
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess)
+  {
+    printf("error in deformable_im2col: %s\n", cudaGetErrorString(err));
+  }
+}
+
+template <typename scalar_t>
+__global__ void deformable_col2im_gpu_kernel(
+    const int n, const scalar_t *data_col, const scalar_t *data_offset,
+    const int channels, const int height, const int width,
+    const int kernel_h, const int kernel_w,
+    const int pad_h, const int pad_w,
+    const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w,
+    const int channel_per_deformable_group,
+    const int batch_size, const int deformable_group,
+    const int height_col, const int width_col,
+    scalar_t *grad_im)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    const int j = (index / width_col / height_col / batch_size) % kernel_w;
+    const int i = (index / width_col / height_col / batch_size / kernel_w) % kernel_h;
+    const int c = index / width_col / height_col / batch_size / kernel_w / kernel_h;
+    // compute the start and end of the output
+
+    const int deformable_group_index = c / channel_per_deformable_group;
+
+    int w_out = index % width_col;
+    int h_out = (index / width_col) % height_col;
+    int b = (index / width_col / height_col) % batch_size;
+    int w_in = w_out * stride_w - pad_w;
+    int h_in = h_out * stride_h - pad_h;
+
+    const scalar_t *data_offset_ptr = data_offset + (b * deformable_group + deformable_group_index) *
+                                                        2 * kernel_h * kernel_w * height_col * width_col;
+    const int data_offset_h_ptr = ((2 * (i * kernel_w + j)) * height_col + h_out) * width_col + w_out;
+    const int data_offset_w_ptr = ((2 * (i * kernel_w + j) + 1) * height_col + h_out) * width_col + w_out;
+    const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+    const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+    const scalar_t cur_inv_h_data = h_in + i * dilation_h + offset_h;
+    const scalar_t cur_inv_w_data = w_in + j * dilation_w + offset_w;
+
+    const scalar_t cur_top_grad = data_col[index];
+    const int cur_h = (int)cur_inv_h_data;
+    const int cur_w = (int)cur_inv_w_data;
+    for (int dy = -2; dy <= 2; dy++)
+    {
+      for (int dx = -2; dx <= 2; dx++)
+      {
+        if (cur_h + dy >= 0 && cur_h + dy < height &&
+            cur_w + dx >= 0 && cur_w + dx < width &&
+            abs(cur_inv_h_data - (cur_h + dy)) < 1 &&
+            abs(cur_inv_w_data - (cur_w + dx)) < 1)
+        {
+          int cur_bottom_grad_pos = ((b * channels + c) * height + cur_h + dy) * width + cur_w + dx;
+          scalar_t weight = get_gradient_weight(cur_inv_h_data, cur_inv_w_data, cur_h + dy, cur_w + dx, height, width);
+          atomicAdd(grad_im + cur_bottom_grad_pos, weight * cur_top_grad);
+        }
+      }
+    }
+  }
+}
+
+void deformable_col2im(
+    const at::Tensor data_col, const at::Tensor data_offset, const int channels,
+    const int height, const int width, const int ksize_h,
+    const int ksize_w, const int pad_h, const int pad_w,
+    const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w,
+    const int parallel_imgs, const int deformable_group,
+    at::Tensor grad_im)
+{
+
+  // todo: make sure parallel_imgs is passed in correctly
+  int height_col = (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
+  int width_col = (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
+  int num_kernels = channels * ksize_h * ksize_w * height_col * width_col * parallel_imgs;
+  int channel_per_deformable_group = channels / deformable_group;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_col.scalar_type(), "deformable_col2im_gpu", ([&] {
+        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        scalar_t *grad_im_ = grad_im.data_ptr<scalar_t>();
+
+        deformable_col2im_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_col_, data_offset_, channels, height, width, ksize_h,
+            ksize_w, pad_h, pad_w, stride_h, stride_w,
+            dilation_h, dilation_w, channel_per_deformable_group,
+            parallel_imgs, deformable_group, height_col, width_col, grad_im_);
+      }));
+
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess)
+  {
+    printf("error in deformable_col2im: %s\n", cudaGetErrorString(err));
+  }
+}
+
+template <typename scalar_t>
+__global__ void deformable_col2im_coord_gpu_kernel(const int n, const scalar_t *data_col,
+                                                   const scalar_t *data_im, const scalar_t *data_offset,
+                                                   const int channels, const int height, const int width,
+                                                   const int kernel_h, const int kernel_w,
+                                                   const int pad_h, const int pad_w,
+                                                   const int stride_h, const int stride_w,
+                                                   const int dilation_h, const int dilation_w,
+                                                   const int channel_per_deformable_group,
+                                                   const int batch_size, const int offset_channels, const int deformable_group,
+                                                   const int height_col, const int width_col, scalar_t *grad_offset)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    scalar_t val = 0;
+    int w = index % width_col;
+    int h = (index / width_col) % height_col;
+    int c = (index / width_col / height_col) % offset_channels;
+    int b = (index / width_col / height_col) / offset_channels;
+    // compute the start and end of the output
+
+    const int deformable_group_index = c / (2 * kernel_h * kernel_w);
+    const int col_step = kernel_h * kernel_w;
+    int cnt = 0;
+    const scalar_t *data_col_ptr = data_col + deformable_group_index * channel_per_deformable_group *
+                                                  batch_size * width_col * height_col;
+    const scalar_t *data_im_ptr = data_im + (b * deformable_group + deformable_group_index) *
+                                                channel_per_deformable_group / kernel_h / kernel_w * height * width;
+    const scalar_t *data_offset_ptr = data_offset + (b * deformable_group + deformable_group_index) * 2 *
+                                                        kernel_h * kernel_w * height_col * width_col;
+
+    const int offset_c = c - deformable_group_index * 2 * kernel_h * kernel_w;
+
+    for (int col_c = (offset_c / 2); col_c < channel_per_deformable_group; col_c += col_step)
+    {
+      const int col_pos = (((col_c * batch_size + b) * height_col) + h) * width_col + w;
+      const int bp_dir = offset_c % 2;
+
+      int j = (col_pos / width_col / height_col / batch_size) % kernel_w;
+      int i = (col_pos / width_col / height_col / batch_size / kernel_w) % kernel_h;
+      int w_out = col_pos % width_col;
+      int h_out = (col_pos / width_col) % height_col;
+      int w_in = w_out * stride_w - pad_w;
+      int h_in = h_out * stride_h - pad_h;
+      const int data_offset_h_ptr = (((2 * (i * kernel_w + j)) * height_col + h_out) * width_col + w_out);
+      const int data_offset_w_ptr = (((2 * (i * kernel_w + j) + 1) * height_col + h_out) * width_col + w_out);
+      const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+      const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+      scalar_t inv_h = h_in + i * dilation_h + offset_h;
+      scalar_t inv_w = w_in + j * dilation_w + offset_w;
+      if (inv_h <= -1 || inv_w <= -1 || inv_h >= height || inv_w >= width)
+      {
+        inv_h = inv_w = -2;
+      }
+      const scalar_t weight = get_coordinate_weight(
+          inv_h, inv_w,
+          height, width, data_im_ptr + cnt * height * width, width, bp_dir);
+      val += weight * data_col_ptr[col_pos];
+      cnt += 1;
+    }
+
+    grad_offset[index] = val;
+  }
+}
+
+void deformable_col2im_coord(
+    const at::Tensor data_col, const at::Tensor data_im, const at::Tensor data_offset,
+    const int channels, const int height, const int width, const int ksize_h,
+    const int ksize_w, const int pad_h, const int pad_w, const int stride_h,
+    const int stride_w, const int dilation_h, const int dilation_w,
+    const int parallel_imgs, const int deformable_group, at::Tensor grad_offset)
+{
+
+  int height_col = (height + 2 * pad_h - (dilation_h * (ksize_h - 1) + 1)) / stride_h + 1;
+  int width_col = (width + 2 * pad_w - (dilation_w * (ksize_w - 1) + 1)) / stride_w + 1;
+  int num_kernels = height_col * width_col * 2 * ksize_h * ksize_w * deformable_group * parallel_imgs;
+  int channel_per_deformable_group = channels * ksize_h * ksize_w / deformable_group;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_col.scalar_type(), "deformable_col2im_coord_gpu", ([&] {
+        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        scalar_t *grad_offset_ = grad_offset.data_ptr<scalar_t>();
+
+        deformable_col2im_coord_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_col_, data_im_, data_offset_, channels, height, width,
+            ksize_h, ksize_w, pad_h, pad_w, stride_h, stride_w,
+            dilation_h, dilation_w, channel_per_deformable_group,
+            parallel_imgs, 2 * ksize_h * ksize_w * deformable_group, deformable_group,
+            height_col, width_col, grad_offset_);
+      }));
+}
+
+template <typename scalar_t>
+__device__ scalar_t dmcn_im2col_bilinear(const scalar_t *bottom_data, const int data_width,
+                                         const int height, const int width, scalar_t h, scalar_t w)
+{
+  int h_low = floor(h);
+  int w_low = floor(w);
+  int h_high = h_low + 1;
+  int w_high = w_low + 1;
+
+  scalar_t lh = h - h_low;
+  scalar_t lw = w - w_low;
+  scalar_t hh = 1 - lh, hw = 1 - lw;
+
+  scalar_t v1 = 0;
+  if (h_low >= 0 && w_low >= 0)
+    v1 = bottom_data[h_low * data_width + w_low];
+  scalar_t v2 = 0;
+  if (h_low >= 0 && w_high <= width - 1)
+    v2 = bottom_data[h_low * data_width + w_high];
+  scalar_t v3 = 0;
+  if (h_high <= height - 1 && w_low >= 0)
+    v3 = bottom_data[h_high * data_width + w_low];
+  scalar_t v4 = 0;
+  if (h_high <= height - 1 && w_high <= width - 1)
+    v4 = bottom_data[h_high * data_width + w_high];
+
+  scalar_t w1 = hh * hw, w2 = hh * lw, w3 = lh * hw, w4 = lh * lw;
+
+  scalar_t val = (w1 * v1 + w2 * v2 + w3 * v3 + w4 * v4);
+  return val;
+}
+
+template <typename scalar_t>
+__device__ scalar_t dmcn_get_gradient_weight(scalar_t argmax_h, scalar_t argmax_w,
+                                             const int h, const int w, const int height, const int width)
+{
+  if (argmax_h <= -1 || argmax_h >= height || argmax_w <= -1 || argmax_w >= width)
+  {
+    //empty
+    return 0;
+  }
+
+  int argmax_h_low = floor(argmax_h);
+  int argmax_w_low = floor(argmax_w);
+  int argmax_h_high = argmax_h_low + 1;
+  int argmax_w_high = argmax_w_low + 1;
+
+  scalar_t weight = 0;
+  if (h == argmax_h_low && w == argmax_w_low)
+    weight = (h + 1 - argmax_h) * (w + 1 - argmax_w);
+  if (h == argmax_h_low && w == argmax_w_high)
+    weight = (h + 1 - argmax_h) * (argmax_w + 1 - w);
+  if (h == argmax_h_high && w == argmax_w_low)
+    weight = (argmax_h + 1 - h) * (w + 1 - argmax_w);
+  if (h == argmax_h_high && w == argmax_w_high)
+    weight = (argmax_h + 1 - h) * (argmax_w + 1 - w);
+  return weight;
+}
+
+template <typename scalar_t>
+__device__ scalar_t dmcn_get_coordinate_weight(scalar_t argmax_h, scalar_t argmax_w,
+                                               const int height, const int width, const scalar_t *im_data,
+                                               const int data_width, const int bp_dir)
+{
+  if (argmax_h <= -1 || argmax_h >= height || argmax_w <= -1 || argmax_w >= width)
+  {
+    //empty
+    return 0;
+  }
+
+  int argmax_h_low = floor(argmax_h);
+  int argmax_w_low = floor(argmax_w);
+  int argmax_h_high = argmax_h_low + 1;
+  int argmax_w_high = argmax_w_low + 1;
+
+  scalar_t weight = 0;
+
+  if (bp_dir == 0)
+  {
+    if (argmax_h_low >= 0 && argmax_w_low >= 0)
+      weight += -1 * (argmax_w_low + 1 - argmax_w) * im_data[argmax_h_low * data_width + argmax_w_low];
+    if (argmax_h_low >= 0 && argmax_w_high <= width - 1)
+      weight += -1 * (argmax_w - argmax_w_low) * im_data[argmax_h_low * data_width + argmax_w_high];
+    if (argmax_h_high <= height - 1 && argmax_w_low >= 0)
+      weight += (argmax_w_low + 1 - argmax_w) * im_data[argmax_h_high * data_width + argmax_w_low];
+    if (argmax_h_high <= height - 1 && argmax_w_high <= width - 1)
+      weight += (argmax_w - argmax_w_low) * im_data[argmax_h_high * data_width + argmax_w_high];
+  }
+  else if (bp_dir == 1)
+  {
+    if (argmax_h_low >= 0 && argmax_w_low >= 0)
+      weight += -1 * (argmax_h_low + 1 - argmax_h) * im_data[argmax_h_low * data_width + argmax_w_low];
+    if (argmax_h_low >= 0 && argmax_w_high <= width - 1)
+      weight += (argmax_h_low + 1 - argmax_h) * im_data[argmax_h_low * data_width + argmax_w_high];
+    if (argmax_h_high <= height - 1 && argmax_w_low >= 0)
+      weight += -1 * (argmax_h - argmax_h_low) * im_data[argmax_h_high * data_width + argmax_w_low];
+    if (argmax_h_high <= height - 1 && argmax_w_high <= width - 1)
+      weight += (argmax_h - argmax_h_low) * im_data[argmax_h_high * data_width + argmax_w_high];
+  }
+
+  return weight;
+}
+
+template <typename scalar_t>
+__global__ void modulated_deformable_im2col_gpu_kernel(const int n,
+                                                       const scalar_t *data_im, const scalar_t *data_offset, const scalar_t *data_mask,
+                                                       const int height, const int width, const int kernel_h, const int kernel_w,
+                                                       const int pad_h, const int pad_w,
+                                                       const int stride_h, const int stride_w,
+                                                       const int dilation_h, const int dilation_w,
+                                                       const int channel_per_deformable_group,
+                                                       const int batch_size, const int num_channels, const int deformable_group,
+                                                       const int height_col, const int width_col,
+                                                       scalar_t *data_col)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    // index index of output matrix
+    const int w_col = index % width_col;
+    const int h_col = (index / width_col) % height_col;
+    const int b_col = (index / width_col / height_col) % batch_size;
+    const int c_im = (index / width_col / height_col) / batch_size;
+    const int c_col = c_im * kernel_h * kernel_w;
+
+    // compute deformable group index
+    const int deformable_group_index = c_im / channel_per_deformable_group;
+
+    const int h_in = h_col * stride_h - pad_h;
+    const int w_in = w_col * stride_w - pad_w;
+
+    scalar_t *data_col_ptr = data_col + ((c_col * batch_size + b_col) * height_col + h_col) * width_col + w_col;
+    //const float* data_im_ptr = data_im + ((b_col * num_channels + c_im) * height + h_in) * width + w_in;
+    const scalar_t *data_im_ptr = data_im + (b_col * num_channels + c_im) * height * width;
+    const scalar_t *data_offset_ptr = data_offset + (b_col * deformable_group + deformable_group_index) * 2 * kernel_h * kernel_w * height_col * width_col;
+
+    const scalar_t *data_mask_ptr = data_mask + (b_col * deformable_group + deformable_group_index) * kernel_h * kernel_w * height_col * width_col;
+
+    for (int i = 0; i < kernel_h; ++i)
+    {
+      for (int j = 0; j < kernel_w; ++j)
+      {
+        const int data_offset_h_ptr = ((2 * (i * kernel_w + j)) * height_col + h_col) * width_col + w_col;
+        const int data_offset_w_ptr = ((2 * (i * kernel_w + j) + 1) * height_col + h_col) * width_col + w_col;
+        const int data_mask_hw_ptr = ((i * kernel_w + j) * height_col + h_col) * width_col + w_col;
+        const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+        const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+        const scalar_t mask = data_mask_ptr[data_mask_hw_ptr];
+        scalar_t val = static_cast<scalar_t>(0);
+        const scalar_t h_im = h_in + i * dilation_h + offset_h;
+        const scalar_t w_im = w_in + j * dilation_w + offset_w;
+        //if (h_im >= 0 && w_im >= 0 && h_im < height && w_im < width) {
+        if (h_im > -1 && w_im > -1 && h_im < height && w_im < width)
+        {
+          //const float map_h = i * dilation_h + offset_h;
+          //const float map_w = j * dilation_w + offset_w;
+          //const int cur_height = height - h_in;
+          //const int cur_width = width - w_in;
+          //val = dmcn_im2col_bilinear(data_im_ptr, width, cur_height, cur_width, map_h, map_w);
+          val = dmcn_im2col_bilinear(data_im_ptr, width, height, width, h_im, w_im);
+        }
+        *data_col_ptr = val * mask;
+        data_col_ptr += batch_size * height_col * width_col;
+        //data_col_ptr += height_col * width_col;
+      }
+    }
+  }
+}
+
+template <typename scalar_t>
+__global__ void modulated_deformable_col2im_gpu_kernel(const int n,
+                                                       const scalar_t *data_col, const scalar_t *data_offset, const scalar_t *data_mask,
+                                                       const int channels, const int height, const int width,
+                                                       const int kernel_h, const int kernel_w,
+                                                       const int pad_h, const int pad_w,
+                                                       const int stride_h, const int stride_w,
+                                                       const int dilation_h, const int dilation_w,
+                                                       const int channel_per_deformable_group,
+                                                       const int batch_size, const int deformable_group,
+                                                       const int height_col, const int width_col,
+                                                       scalar_t *grad_im)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    const int j = (index / width_col / height_col / batch_size) % kernel_w;
+    const int i = (index / width_col / height_col / batch_size / kernel_w) % kernel_h;
+    const int c = index / width_col / height_col / batch_size / kernel_w / kernel_h;
+    // compute the start and end of the output
+
+    const int deformable_group_index = c / channel_per_deformable_group;
+
+    int w_out = index % width_col;
+    int h_out = (index / width_col) % height_col;
+    int b = (index / width_col / height_col) % batch_size;
+    int w_in = w_out * stride_w - pad_w;
+    int h_in = h_out * stride_h - pad_h;
+
+    const scalar_t *data_offset_ptr = data_offset + (b * deformable_group + deformable_group_index) * 2 * kernel_h * kernel_w * height_col * width_col;
+    const scalar_t *data_mask_ptr = data_mask + (b * deformable_group + deformable_group_index) * kernel_h * kernel_w * height_col * width_col;
+    const int data_offset_h_ptr = ((2 * (i * kernel_w + j)) * height_col + h_out) * width_col + w_out;
+    const int data_offset_w_ptr = ((2 * (i * kernel_w + j) + 1) * height_col + h_out) * width_col + w_out;
+    const int data_mask_hw_ptr = ((i * kernel_w + j) * height_col + h_out) * width_col + w_out;
+    const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+    const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+    const scalar_t mask = data_mask_ptr[data_mask_hw_ptr];
+    const scalar_t cur_inv_h_data = h_in + i * dilation_h + offset_h;
+    const scalar_t cur_inv_w_data = w_in + j * dilation_w + offset_w;
+
+    const scalar_t cur_top_grad = data_col[index] * mask;
+    const int cur_h = (int)cur_inv_h_data;
+    const int cur_w = (int)cur_inv_w_data;
+    for (int dy = -2; dy <= 2; dy++)
+    {
+      for (int dx = -2; dx <= 2; dx++)
+      {
+        if (cur_h + dy >= 0 && cur_h + dy < height &&
+            cur_w + dx >= 0 && cur_w + dx < width &&
+            abs(cur_inv_h_data - (cur_h + dy)) < 1 &&
+            abs(cur_inv_w_data - (cur_w + dx)) < 1)
+        {
+          int cur_bottom_grad_pos = ((b * channels + c) * height + cur_h + dy) * width + cur_w + dx;
+          scalar_t weight = dmcn_get_gradient_weight(cur_inv_h_data, cur_inv_w_data, cur_h + dy, cur_w + dx, height, width);
+          atomicAdd(grad_im + cur_bottom_grad_pos, weight * cur_top_grad);
+        }
+      }
+    }
+  }
+}
+
+template <typename scalar_t>
+__global__ void modulated_deformable_col2im_coord_gpu_kernel(const int n,
+                                                             const scalar_t *data_col, const scalar_t *data_im,
+                                                             const scalar_t *data_offset, const scalar_t *data_mask,
+                                                             const int channels, const int height, const int width,
+                                                             const int kernel_h, const int kernel_w,
+                                                             const int pad_h, const int pad_w,
+                                                             const int stride_h, const int stride_w,
+                                                             const int dilation_h, const int dilation_w,
+                                                             const int channel_per_deformable_group,
+                                                             const int batch_size, const int offset_channels, const int deformable_group,
+                                                             const int height_col, const int width_col,
+                                                             scalar_t *grad_offset, scalar_t *grad_mask)
+{
+  CUDA_KERNEL_LOOP(index, n)
+  {
+    scalar_t val = 0, mval = 0;
+    int w = index % width_col;
+    int h = (index / width_col) % height_col;
+    int c = (index / width_col / height_col) % offset_channels;
+    int b = (index / width_col / height_col) / offset_channels;
+    // compute the start and end of the output
+
+    const int deformable_group_index = c / (2 * kernel_h * kernel_w);
+    const int col_step = kernel_h * kernel_w;
+    int cnt = 0;
+    const scalar_t *data_col_ptr = data_col + deformable_group_index * channel_per_deformable_group * batch_size * width_col * height_col;
+    const scalar_t *data_im_ptr = data_im + (b * deformable_group + deformable_group_index) * channel_per_deformable_group / kernel_h / kernel_w * height * width;
+    const scalar_t *data_offset_ptr = data_offset + (b * deformable_group + deformable_group_index) * 2 * kernel_h * kernel_w * height_col * width_col;
+    const scalar_t *data_mask_ptr = data_mask + (b * deformable_group + deformable_group_index) * kernel_h * kernel_w * height_col * width_col;
+
+    const int offset_c = c - deformable_group_index * 2 * kernel_h * kernel_w;
+
+    for (int col_c = (offset_c / 2); col_c < channel_per_deformable_group; col_c += col_step)
+    {
+      const int col_pos = (((col_c * batch_size + b) * height_col) + h) * width_col + w;
+      const int bp_dir = offset_c % 2;
+
+      int j = (col_pos / width_col / height_col / batch_size) % kernel_w;
+      int i = (col_pos / width_col / height_col / batch_size / kernel_w) % kernel_h;
+      int w_out = col_pos % width_col;
+      int h_out = (col_pos / width_col) % height_col;
+      int w_in = w_out * stride_w - pad_w;
+      int h_in = h_out * stride_h - pad_h;
+      const int data_offset_h_ptr = (((2 * (i * kernel_w + j)) * height_col + h_out) * width_col + w_out);
+      const int data_offset_w_ptr = (((2 * (i * kernel_w + j) + 1) * height_col + h_out) * width_col + w_out);
+      const int data_mask_hw_ptr = (((i * kernel_w + j) * height_col + h_out) * width_col + w_out);
+      const scalar_t offset_h = data_offset_ptr[data_offset_h_ptr];
+      const scalar_t offset_w = data_offset_ptr[data_offset_w_ptr];
+      const scalar_t mask = data_mask_ptr[data_mask_hw_ptr];
+      scalar_t inv_h = h_in + i * dilation_h + offset_h;
+      scalar_t inv_w = w_in + j * dilation_w + offset_w;
+      if (inv_h <= -1 || inv_w <= -1 || inv_h >= height || inv_w >= width)
+      {
+        inv_h = inv_w = -2;
+      }
+      else
+      {
+        mval += data_col_ptr[col_pos] * dmcn_im2col_bilinear(data_im_ptr + cnt * height * width, width, height, width, inv_h, inv_w);
+      }
+      const scalar_t weight = dmcn_get_coordinate_weight(
+          inv_h, inv_w,
+          height, width, data_im_ptr + cnt * height * width, width, bp_dir);
+      val += weight * data_col_ptr[col_pos] * mask;
+      cnt += 1;
+    }
+    // KERNEL_ASSIGN(grad_offset[index], offset_req, val);
+    grad_offset[index] = val;
+    if (offset_c % 2 == 0)
+      // KERNEL_ASSIGN(grad_mask[(((b * deformable_group + deformable_group_index) * kernel_h * kernel_w + offset_c / 2) * height_col + h) * width_col + w], mask_req, mval);
+      grad_mask[(((b * deformable_group + deformable_group_index) * kernel_h * kernel_w + offset_c / 2) * height_col + h) * width_col + w] = mval;
+  }
+}
+
+void modulated_deformable_im2col_cuda(
+    const at::Tensor data_im, const at::Tensor data_offset, const at::Tensor data_mask,
+    const int batch_size, const int channels, const int height_im, const int width_im,
+    const int height_col, const int width_col, const int kernel_h, const int kenerl_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w,
+    const int deformable_group, at::Tensor data_col)
+{
+  // num_axes should be smaller than block size
+  const int channel_per_deformable_group = channels / deformable_group;
+  const int num_kernels = channels * batch_size * height_col * width_col;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_im.scalar_type(), "modulated_deformable_im2col_gpu", ([&] {
+        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        const scalar_t *data_mask_ = data_mask.data_ptr<scalar_t>();
+        scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+
+        modulated_deformable_im2col_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_im_, data_offset_, data_mask_, height_im, width_im, kernel_h, kenerl_w,
+            pad_h, pad_w, stride_h, stride_w, dilation_h, dilation_w, channel_per_deformable_group,
+            batch_size, channels, deformable_group, height_col, width_col, data_col_);
+      }));
+
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess)
+  {
+    printf("error in modulated_deformable_im2col_cuda: %s\n", cudaGetErrorString(err));
+  }
+}
+
+void modulated_deformable_col2im_cuda(
+    const at::Tensor data_col, const at::Tensor data_offset, const at::Tensor data_mask,
+    const int batch_size, const int channels, const int height_im, const int width_im,
+    const int height_col, const int width_col, const int kernel_h, const int kernel_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w,
+    const int deformable_group, at::Tensor grad_im)
+{
+
+  const int channel_per_deformable_group = channels / deformable_group;
+  const int num_kernels = channels * kernel_h * kernel_w * batch_size * height_col * width_col;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_col.scalar_type(), "modulated_deformable_col2im_gpu", ([&] {
+        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        const scalar_t *data_mask_ = data_mask.data_ptr<scalar_t>();
+        scalar_t *grad_im_ = grad_im.data_ptr<scalar_t>();
+
+        modulated_deformable_col2im_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_col_, data_offset_, data_mask_, channels, height_im, width_im,
+            kernel_h, kernel_w, pad_h, pad_w, stride_h, stride_w,
+            dilation_h, dilation_w, channel_per_deformable_group,
+            batch_size, deformable_group, height_col, width_col, grad_im_);
+      }));
+
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess)
+  {
+    printf("error in modulated_deformable_col2im_cuda: %s\n", cudaGetErrorString(err));
+  }
+}
+
+void modulated_deformable_col2im_coord_cuda(
+    const at::Tensor data_col, const at::Tensor data_im, const at::Tensor data_offset, const at::Tensor data_mask,
+    const int batch_size, const int channels, const int height_im, const int width_im,
+    const int height_col, const int width_col, const int kernel_h, const int kernel_w,
+    const int pad_h, const int pad_w, const int stride_h, const int stride_w,
+    const int dilation_h, const int dilation_w,
+    const int deformable_group,
+    at::Tensor grad_offset, at::Tensor grad_mask)
+{
+  const int num_kernels = batch_size * height_col * width_col * 2 * kernel_h * kernel_w * deformable_group;
+  const int channel_per_deformable_group = channels * kernel_h * kernel_w / deformable_group;
+
+  AT_DISPATCH_FLOATING_TYPES_AND_HALF(
+      data_col.scalar_type(), "modulated_deformable_col2im_coord_gpu", ([&] {
+        const scalar_t *data_col_ = data_col.data_ptr<scalar_t>();
+        const scalar_t *data_im_ = data_im.data_ptr<scalar_t>();
+        const scalar_t *data_offset_ = data_offset.data_ptr<scalar_t>();
+        const scalar_t *data_mask_ = data_mask.data_ptr<scalar_t>();
+        scalar_t *grad_offset_ = grad_offset.data_ptr<scalar_t>();
+        scalar_t *grad_mask_ = grad_mask.data_ptr<scalar_t>();
+
+        modulated_deformable_col2im_coord_gpu_kernel<<<GET_BLOCKS(num_kernels), CUDA_NUM_THREADS, 0, at::cuda::getCurrentCUDAStream()>>>(
+            num_kernels, data_col_, data_im_, data_offset_, data_mask_, channels, height_im, width_im,
+            kernel_h, kernel_w, pad_h, pad_w, stride_h, stride_w,
+            dilation_h, dilation_w, channel_per_deformable_group,
+            batch_size, 2 * kernel_h * kernel_w * deformable_group, deformable_group, height_col, width_col,
+            grad_offset_, grad_mask_);
+      }));
+  cudaError_t err = cudaGetLastError();
+  if (err != cudaSuccess)
+  {
+    printf("error in modulated_deformable_col2im_coord_cuda: %s\n", cudaGetErrorString(err));
+  }
+}

basicsr/ops/dcn/src/deform_conv_ext.cpp

+// modify from
+// https://github.com/chengdazhi/Deformable-Convolution-V2-PyTorch/blob/mmdetection/mmdet/ops/dcn/src/deform_conv_cuda.c
+
+#include <torch/extension.h>
+#include <ATen/DeviceGuard.h>
+
+#include <cmath>
+#include <vector>
+
+#define WITH_CUDA  // always use cuda
+#ifdef WITH_CUDA
+int deform_conv_forward_cuda(at::Tensor input, at::Tensor weight,
+                             at::Tensor offset, at::Tensor output,
+                             at::Tensor columns, at::Tensor ones, int kW,
+                             int kH, int dW, int dH, int padW, int padH,
+                             int dilationW, int dilationH, int group,
+                             int deformable_group, int im2col_step);
+
+int deform_conv_backward_input_cuda(at::Tensor input, at::Tensor offset,
+                                    at::Tensor gradOutput, at::Tensor gradInput,
+                                    at::Tensor gradOffset, at::Tensor weight,
+                                    at::Tensor columns, int kW, int kH, int dW,
+                                    int dH, int padW, int padH, int dilationW,
+                                    int dilationH, int group,
+                                    int deformable_group, int im2col_step);
+
+int deform_conv_backward_parameters_cuda(
+    at::Tensor input, at::Tensor offset, at::Tensor gradOutput,
+    at::Tensor gradWeight,  // at::Tensor gradBias,
+    at::Tensor columns, at::Tensor ones, int kW, int kH, int dW, int dH,
+    int padW, int padH, int dilationW, int dilationH, int group,
+    int deformable_group, float scale, int im2col_step);
+
+void modulated_deform_conv_cuda_forward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor output, at::Tensor columns,
+    int kernel_h, int kernel_w, const int stride_h, const int stride_w,
+    const int pad_h, const int pad_w, const int dilation_h,
+    const int dilation_w, const int group, const int deformable_group,
+    const bool with_bias);
+
+void modulated_deform_conv_cuda_backward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor columns,
+    at::Tensor grad_input, at::Tensor grad_weight, at::Tensor grad_bias,
+    at::Tensor grad_offset, at::Tensor grad_mask, at::Tensor grad_output,
+    int kernel_h, int kernel_w, int stride_h, int stride_w, int pad_h,
+    int pad_w, int dilation_h, int dilation_w, int group, int deformable_group,
+    const bool with_bias);
+#endif
+
+int deform_conv_forward(at::Tensor input, at::Tensor weight,
+                             at::Tensor offset, at::Tensor output,
+                             at::Tensor columns, at::Tensor ones, int kW,
+                             int kH, int dW, int dH, int padW, int padH,
+                             int dilationW, int dilationH, int group,
+                             int deformable_group, int im2col_step) {
+  if (input.device().is_cuda()) {
+#ifdef WITH_CUDA
+    return deform_conv_forward_cuda(input, weight, offset, output, columns,
+        ones, kW, kH, dW, dH, padW, padH, dilationW, dilationH, group,
+        deformable_group, im2col_step);
+#else
+    AT_ERROR("deform conv is not compiled with GPU support");
+#endif
+  }
+  AT_ERROR("deform conv is not implemented on CPU");
+}
+
+int deform_conv_backward_input(at::Tensor input, at::Tensor offset,
+                                    at::Tensor gradOutput, at::Tensor gradInput,
+                                    at::Tensor gradOffset, at::Tensor weight,
+                                    at::Tensor columns, int kW, int kH, int dW,
+                                    int dH, int padW, int padH, int dilationW,
+                                    int dilationH, int group,
+                                    int deformable_group, int im2col_step) {
+  if (input.device().is_cuda()) {
+#ifdef WITH_CUDA
+    return deform_conv_backward_input_cuda(input, offset, gradOutput,
+        gradInput, gradOffset, weight, columns, kW, kH, dW, dH, padW, padH,
+        dilationW, dilationH, group, deformable_group, im2col_step);
+#else
+    AT_ERROR("deform conv is not compiled with GPU support");
+#endif
+  }
+  AT_ERROR("deform conv is not implemented on CPU");
+}
+
+int deform_conv_backward_parameters(
+    at::Tensor input, at::Tensor offset, at::Tensor gradOutput,
+    at::Tensor gradWeight,  // at::Tensor gradBias,
+    at::Tensor columns, at::Tensor ones, int kW, int kH, int dW, int dH,
+    int padW, int padH, int dilationW, int dilationH, int group,
+    int deformable_group, float scale, int im2col_step) {
+  if (input.device().is_cuda()) {
+#ifdef WITH_CUDA
+    return deform_conv_backward_parameters_cuda(input, offset, gradOutput,
+        gradWeight, columns, ones, kW, kH, dW, dH, padW, padH, dilationW,
+        dilationH, group, deformable_group, scale, im2col_step);
+#else
+    AT_ERROR("deform conv is not compiled with GPU support");
+#endif
+  }
+  AT_ERROR("deform conv is not implemented on CPU");
+}
+
+void modulated_deform_conv_forward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor output, at::Tensor columns,
+    int kernel_h, int kernel_w, const int stride_h, const int stride_w,
+    const int pad_h, const int pad_w, const int dilation_h,
+    const int dilation_w, const int group, const int deformable_group,
+    const bool with_bias) {
+  if (input.device().is_cuda()) {
+#ifdef WITH_CUDA
+    return modulated_deform_conv_cuda_forward(input, weight, bias, ones,
+        offset, mask, output, columns, kernel_h, kernel_w, stride_h,
+        stride_w, pad_h, pad_w, dilation_h, dilation_w, group,
+        deformable_group, with_bias);
+#else
+    AT_ERROR("modulated deform conv is not compiled with GPU support");
+#endif
+  }
+  AT_ERROR("modulated deform conv is not implemented on CPU");
+}
+
+void modulated_deform_conv_backward(
+    at::Tensor input, at::Tensor weight, at::Tensor bias, at::Tensor ones,
+    at::Tensor offset, at::Tensor mask, at::Tensor columns,
+    at::Tensor grad_input, at::Tensor grad_weight, at::Tensor grad_bias,
+    at::Tensor grad_offset, at::Tensor grad_mask, at::Tensor grad_output,
+    int kernel_h, int kernel_w, int stride_h, int stride_w, int pad_h,
+    int pad_w, int dilation_h, int dilation_w, int group, int deformable_group,
+    const bool with_bias) {
+  if (input.device().is_cuda()) {
+#ifdef WITH_CUDA
+    return modulated_deform_conv_cuda_backward(input, weight, bias, ones,
+        offset, mask, columns, grad_input, grad_weight, grad_bias, grad_offset,
+        grad_mask, grad_output, kernel_h, kernel_w, stride_h, stride_w,
+        pad_h, pad_w, dilation_h, dilation_w, group, deformable_group,
+        with_bias);
+#else
+    AT_ERROR("modulated deform conv is not compiled with GPU support");
+#endif
+  }
+  AT_ERROR("modulated deform conv is not implemented on CPU");
+}
+
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+  m.def("deform_conv_forward", &deform_conv_forward,
+        "deform forward");
+  m.def("deform_conv_backward_input", &deform_conv_backward_input,
+        "deform_conv_backward_input");
+  m.def("deform_conv_backward_parameters",
+        &deform_conv_backward_parameters,
+        "deform_conv_backward_parameters");
+  m.def("modulated_deform_conv_forward",
+        &modulated_deform_conv_forward,
+        "modulated deform conv forward");
+  m.def("modulated_deform_conv_backward",
+        &modulated_deform_conv_backward,
+        "modulated deform conv backward");
+}

basicsr/ops/fused_act/__init__.py

+from .fused_act import FusedLeakyReLU, fused_leaky_relu
+
+__all__ = ['FusedLeakyReLU', 'fused_leaky_relu']

basicsr/ops/fused_act/fused_act.py

+# modify from https://github.com/rosinality/stylegan2-pytorch/blob/master/op/fused_act.py # noqa:E501
+
+import os
+import torch
+from torch import nn
+from torch.autograd import Function
+
+BASICSR_JIT = os.getenv('BASICSR_JIT')
+if BASICSR_JIT == 'True':
+    from torch.utils.cpp_extension import load
+    module_path = os.path.dirname(__file__)
+    fused_act_ext = load(
+        'fused',
+        sources=[
+            os.path.join(module_path, 'src', 'fused_bias_act.cpp'),
+            os.path.join(module_path, 'src', 'fused_bias_act_kernel.cu'),
+        ],
+    )
+else:
+    try:
+        from . import fused_act_ext
+    except ImportError:
+        pass
+        # avoid annoying print output
+        # print(f'Cannot import deform_conv_ext. Error: {error}. You may need to: \n '
+        #       '1. compile with BASICSR_EXT=True. or\n '
+        #       '2. set BASICSR_JIT=True during running')
+
+
+class FusedLeakyReLUFunctionBackward(Function):
+
+    @staticmethod
+    def forward(ctx, grad_output, out, negative_slope, scale):
+        ctx.save_for_backward(out)
+        ctx.negative_slope = negative_slope
+        ctx.scale = scale
+
+        empty = grad_output.new_empty(0)
+
+        grad_input = fused_act_ext.fused_bias_act(grad_output, empty, out, 3, 1, negative_slope, scale)
+
+        dim = [0]
+
+        if grad_input.ndim > 2:
+            dim += list(range(2, grad_input.ndim))
+
+        grad_bias = grad_input.sum(dim).detach()
+
+        return grad_input, grad_bias
+
+    @staticmethod
+    def backward(ctx, gradgrad_input, gradgrad_bias):
+        out, = ctx.saved_tensors
+        gradgrad_out = fused_act_ext.fused_bias_act(gradgrad_input, gradgrad_bias, out, 3, 1, ctx.negative_slope,
+                                                    ctx.scale)
+
+        return gradgrad_out, None, None, None
+
+
+class FusedLeakyReLUFunction(Function):
+
+    @staticmethod
+    def forward(ctx, input, bias, negative_slope, scale):
+        empty = input.new_empty(0)
+        out = fused_act_ext.fused_bias_act(input, bias, empty, 3, 0, negative_slope, scale)
+        ctx.save_for_backward(out)
+        ctx.negative_slope = negative_slope
+        ctx.scale = scale
+
+        return out
+
+    @staticmethod
+    def backward(ctx, grad_output):
+        out, = ctx.saved_tensors
+
+        grad_input, grad_bias = FusedLeakyReLUFunctionBackward.apply(grad_output, out, ctx.negative_slope, ctx.scale)
+
+        return grad_input, grad_bias, None, None
+
+
+class FusedLeakyReLU(nn.Module):
+
+    def __init__(self, channel, negative_slope=0.2, scale=2**0.5):
+        super().__init__()
+
+        self.bias = nn.Parameter(torch.zeros(channel))
+        self.negative_slope = negative_slope
+        self.scale = scale
+
+    def forward(self, input):
+        return fused_leaky_relu(input, self.bias, self.negative_slope, self.scale)
+
+
+def fused_leaky_relu(input, bias, negative_slope=0.2, scale=2**0.5):
+    return FusedLeakyReLUFunction.apply(input, bias, negative_slope, scale)

basicsr/ops/fused_act/src/fused_bias_act.cpp

+// from https://github.com/rosinality/stylegan2-pytorch/blob/master/op/fused_bias_act.cpp
+#include <torch/extension.h>
+
+
+torch::Tensor fused_bias_act_op(const torch::Tensor& input,
+                                const torch::Tensor& bias,
+                                const torch::Tensor& refer,
+                                int act, int grad, float alpha, float scale);
+
+#define CHECK_CUDA(x) TORCH_CHECK(x.type().is_cuda(), #x " must be a CUDA tensor")
+#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
+#define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)
+
+torch::Tensor fused_bias_act(const torch::Tensor& input,
+                             const torch::Tensor& bias,
+                             const torch::Tensor& refer,
+                             int act, int grad, float alpha, float scale) {
+    CHECK_CUDA(input);
+    CHECK_CUDA(bias);
+
+    return fused_bias_act_op(input, bias, refer, act, grad, alpha, scale);
+}
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+    m.def("fused_bias_act", &fused_bias_act, "fused bias act (CUDA)");
+}

basicsr/ops/fused_act/src/fused_bias_act_kernel.cu

+// from https://github.com/rosinality/stylegan2-pytorch/blob/master/op/fused_bias_act_kernel.cu
+// Copyright (c) 2019, NVIDIA Corporation. All rights reserved.
+//
+// This work is made available under the Nvidia Source Code License-NC.
+// To view a copy of this license, visit
+// https://nvlabs.github.io/stylegan2/license.html
+
+#include <torch/types.h>
+
+#include <ATen/ATen.h>
+#include <ATen/AccumulateType.h>
+#include <ATen/cuda/CUDAContext.h>
+#include <ATen/cuda/CUDAApplyUtils.cuh>
+
+#include <cuda.h>
+#include <cuda_runtime.h>
+
+
+template <typename scalar_t>
+static __global__ void fused_bias_act_kernel(scalar_t* out, const scalar_t* p_x, const scalar_t* p_b, const scalar_t* p_ref,
+    int act, int grad, scalar_t alpha, scalar_t scale, int loop_x, int size_x, int step_b, int size_b, int use_bias, int use_ref) {
+    int xi = blockIdx.x * loop_x * blockDim.x + threadIdx.x;
+
+    scalar_t zero = 0.0;
+
+    for (int loop_idx = 0; loop_idx < loop_x && xi < size_x; loop_idx++, xi += blockDim.x) {
+        scalar_t x = p_x[xi];
+
+        if (use_bias) {
+            x += p_b[(xi / step_b) % size_b];
+        }
+
+        scalar_t ref = use_ref ? p_ref[xi] : zero;
+
+        scalar_t y;
+
+        switch (act * 10 + grad) {
+            default:
+            case 10: y = x; break;
+            case 11: y = x; break;
+            case 12: y = 0.0; break;
+
+            case 30: y = (x > 0.0) ? x : x * alpha; break;
+            case 31: y = (ref > 0.0) ? x : x * alpha; break;
+            case 32: y = 0.0; break;
+        }
+
+        out[xi] = y * scale;
+    }
+}
+
+
+torch::Tensor fused_bias_act_op(const torch::Tensor& input, const torch::Tensor& bias, const torch::Tensor& refer,
+    int act, int grad, float alpha, float scale) {
+    int curDevice = -1;
+    cudaGetDevice(&curDevice);
+    cudaStream_t stream = at::cuda::getCurrentCUDAStream(curDevice);
+
+    auto x = input.contiguous();
+    auto b = bias.contiguous();
+    auto ref = refer.contiguous();
+
+    int use_bias = b.numel() ? 1 : 0;
+    int use_ref = ref.numel() ? 1 : 0;
+
+    int size_x = x.numel();
+    int size_b = b.numel();
+    int step_b = 1;
+
+    for (int i = 1 + 1; i < x.dim(); i++) {
+        step_b *= x.size(i);
+    }
+
+    int loop_x = 4;
+    int block_size = 4 * 32;
+    int grid_size = (size_x - 1) / (loop_x * block_size) + 1;
+
+    auto y = torch::empty_like(x);
+
+    AT_DISPATCH_FLOATING_TYPES_AND_HALF(x.scalar_type(), "fused_bias_act_kernel", [&] {
+        fused_bias_act_kernel<scalar_t><<<grid_size, block_size, 0, stream>>>(
+            y.data_ptr<scalar_t>(),
+            x.data_ptr<scalar_t>(),
+            b.data_ptr<scalar_t>(),
+            ref.data_ptr<scalar_t>(),
+            act,
+            grad,
+            alpha,
+            scale,
+            loop_x,
+            size_x,
+            step_b,
+            size_b,
+            use_bias,
+            use_ref
+        );
+    });
+
+    return y;
+}

basicsr/ops/upfirdn2d/__init__.py

+from .upfirdn2d import upfirdn2d
+
+__all__ = ['upfirdn2d']

basicsr/ops/upfirdn2d/src/upfirdn2d.cpp

+// from https://github.com/rosinality/stylegan2-pytorch/blob/master/op/upfirdn2d.cpp
+#include <torch/extension.h>
+
+
+torch::Tensor upfirdn2d_op(const torch::Tensor& input, const torch::Tensor& kernel,
+                            int up_x, int up_y, int down_x, int down_y,
+                            int pad_x0, int pad_x1, int pad_y0, int pad_y1);
+
+#define CHECK_CUDA(x) TORCH_CHECK(x.type().is_cuda(), #x " must be a CUDA tensor")
+#define CHECK_CONTIGUOUS(x) TORCH_CHECK(x.is_contiguous(), #x " must be contiguous")
+#define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)
+
+torch::Tensor upfirdn2d(const torch::Tensor& input, const torch::Tensor& kernel,
+                        int up_x, int up_y, int down_x, int down_y,
+                        int pad_x0, int pad_x1, int pad_y0, int pad_y1) {
+    CHECK_CUDA(input);
+    CHECK_CUDA(kernel);
+
+    return upfirdn2d_op(input, kernel, up_x, up_y, down_x, down_y, pad_x0, pad_x1, pad_y0, pad_y1);
+}
+
+PYBIND11_MODULE(TORCH_EXTENSION_NAME, m) {
+    m.def("upfirdn2d", &upfirdn2d, "upfirdn2d (CUDA)");
+}