Merge branch 'main' of https://github.com/huggingface/diffusers into main

examples/train_unconditional.py

@@ -21,7 +21,7 @@ from torchvision.transforms import (
     ToTensor,
 )
 from tqdm.auto import tqdm
-from transformers import get_linear_schedule_with_warmup
+from diffusers.optimization import get_scheduler
 
 
 logger = logging.get_logger(__name__)
@@ -60,7 +60,8 @@ def main(args):
     dataset.set_transform(transforms)
     train_dataloader = torch.utils.data.DataLoader(dataset, batch_size=args.batch_size, shuffle=True)
 
-    lr_scheduler = get_linear_schedule_with_warmup(
+    lr_scheduler = get_scheduler(
+        "linear",
         optimizer=optimizer,
         num_warmup_steps=args.warmup_steps,
         num_training_steps=(len(train_dataloader) * args.num_epochs) // args.gradient_accumulation_steps,
@@ -107,11 +108,13 @@ def main(args):
                         output = model(noisy_images, timesteps)
                         # predict the noise residual
                         loss = F.mse_loss(output, noise_samples)
+                        loss = loss / args.gradient_accumulation_steps
                         accelerator.backward(loss)
                 else:
                     output = model(noisy_images, timesteps)
                     # predict the noise residual
                     loss = F.mse_loss(output, noise_samples)
+                    loss = loss / args.gradient_accumulation_steps
                     accelerator.backward(loss)
                     torch.nn.utils.clip_grad_norm_(model.parameters(), 1.0)
                     optimizer.step()

src/diffusers/hub_utils.py

+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
 import os
 import shutil
 from pathlib import Path

src/diffusers/optimization.py

+# coding=utf-8
+# Copyright 2022 The HuggingFace Inc. team.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""PyTorch optimization for diffusion models."""
+
+import math
+from enum import Enum
+from typing import Optional, Union
+
+import torch
+from torch.optim import Optimizer
+from torch.optim.lr_scheduler import LambdaLR
+
+from .utils import logging
+
+
+logger = logging.get_logger(__name__)
+
+
+class SchedulerType(Enum):
+    LINEAR = "linear"
+    COSINE = "cosine"
+    COSINE_WITH_RESTARTS = "cosine_with_restarts"
+    POLYNOMIAL = "polynomial"
+    CONSTANT = "constant"
+    CONSTANT_WITH_WARMUP = "constant_with_warmup"
+
+
+def get_constant_schedule(optimizer: Optimizer, last_epoch: int = -1):
+    """
+    Create a schedule with a constant learning rate, using the learning rate set in optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+    return LambdaLR(optimizer, lambda _: 1, last_epoch=last_epoch)
+
+
+def get_constant_schedule_with_warmup(optimizer: Optimizer, num_warmup_steps: int, last_epoch: int = -1):
+    """
+    Create a schedule with a constant learning rate preceded by a warmup period during which the learning rate
+    increases linearly between 0 and the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1.0, num_warmup_steps))
+        return 1.0
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch=last_epoch)
+
+
+def get_linear_schedule_with_warmup(optimizer, num_warmup_steps, num_training_steps, last_epoch=-1):
+    """
+    Create a schedule with a learning rate that decreases linearly from the initial lr set in the optimizer to 0, after
+    a warmup period during which it increases linearly from 0 to the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        return max(
+            0.0, float(num_training_steps - current_step) / float(max(1, num_training_steps - num_warmup_steps))
+        )
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_cosine_schedule_with_warmup(
+    optimizer: Optimizer, num_warmup_steps: int, num_training_steps: int, num_cycles: float = 0.5, last_epoch: int = -1
+):
+    """
+    Create a schedule with a learning rate that decreases following the values of the cosine function between the
+    initial lr set in the optimizer to 0, after a warmup period during which it increases linearly between 0 and the
+    initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        num_cycles (`float`, *optional*, defaults to 0.5):
+            The number of waves in the cosine schedule (the defaults is to just decrease from the max value to 0
+            following a half-cosine).
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        progress = float(current_step - num_warmup_steps) / float(max(1, num_training_steps - num_warmup_steps))
+        return max(0.0, 0.5 * (1.0 + math.cos(math.pi * float(num_cycles) * 2.0 * progress)))
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_cosine_with_hard_restarts_schedule_with_warmup(
+    optimizer: Optimizer, num_warmup_steps: int, num_training_steps: int, num_cycles: int = 1, last_epoch: int = -1
+):
+    """
+    Create a schedule with a learning rate that decreases following the values of the cosine function between the
+    initial lr set in the optimizer to 0, with several hard restarts, after a warmup period during which it increases
+    linearly between 0 and the initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        num_cycles (`int`, *optional*, defaults to 1):
+            The number of hard restarts to use.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+    """
+
+    def lr_lambda(current_step):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        progress = float(current_step - num_warmup_steps) / float(max(1, num_training_steps - num_warmup_steps))
+        if progress >= 1.0:
+            return 0.0
+        return max(0.0, 0.5 * (1.0 + math.cos(math.pi * ((float(num_cycles) * progress) % 1.0))))
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+def get_polynomial_decay_schedule_with_warmup(
+    optimizer, num_warmup_steps, num_training_steps, lr_end=1e-7, power=1.0, last_epoch=-1
+):
+    """
+    Create a schedule with a learning rate that decreases as a polynomial decay from the initial lr set in the
+    optimizer to end lr defined by *lr_end*, after a warmup period during which it increases linearly from 0 to the
+    initial lr set in the optimizer.
+
+    Args:
+        optimizer ([`~torch.optim.Optimizer`]):
+            The optimizer for which to schedule the learning rate.
+        num_warmup_steps (`int`):
+            The number of steps for the warmup phase.
+        num_training_steps (`int`):
+            The total number of training steps.
+        lr_end (`float`, *optional*, defaults to 1e-7):
+            The end LR.
+        power (`float`, *optional*, defaults to 1.0):
+            Power factor.
+        last_epoch (`int`, *optional*, defaults to -1):
+            The index of the last epoch when resuming training.
+
+    Note: *power* defaults to 1.0 as in the fairseq implementation, which in turn is based on the original BERT
+    implementation at
+    https://github.com/google-research/bert/blob/f39e881b169b9d53bea03d2d341b31707a6c052b/optimization.py#L37
+
+    Return:
+        `torch.optim.lr_scheduler.LambdaLR` with the appropriate schedule.
+
+    """
+
+    lr_init = optimizer.defaults["lr"]
+    if not (lr_init > lr_end):
+        raise ValueError(f"lr_end ({lr_end}) must be be smaller than initial lr ({lr_init})")
+
+    def lr_lambda(current_step: int):
+        if current_step < num_warmup_steps:
+            return float(current_step) / float(max(1, num_warmup_steps))
+        elif current_step > num_training_steps:
+            return lr_end / lr_init  # as LambdaLR multiplies by lr_init
+        else:
+            lr_range = lr_init - lr_end
+            decay_steps = num_training_steps - num_warmup_steps
+            pct_remaining = 1 - (current_step - num_warmup_steps) / decay_steps
+            decay = lr_range * pct_remaining**power + lr_end
+            return decay / lr_init  # as LambdaLR multiplies by lr_init
+
+    return LambdaLR(optimizer, lr_lambda, last_epoch)
+
+
+TYPE_TO_SCHEDULER_FUNCTION = {
+    SchedulerType.LINEAR: get_linear_schedule_with_warmup,
+    SchedulerType.COSINE: get_cosine_schedule_with_warmup,
+    SchedulerType.COSINE_WITH_RESTARTS: get_cosine_with_hard_restarts_schedule_with_warmup,
+    SchedulerType.POLYNOMIAL: get_polynomial_decay_schedule_with_warmup,
+    SchedulerType.CONSTANT: get_constant_schedule,
+    SchedulerType.CONSTANT_WITH_WARMUP: get_constant_schedule_with_warmup,
+}
+
+
+def get_scheduler(
+    name: Union[str, SchedulerType],
+    optimizer: Optimizer,
+    num_warmup_steps: Optional[int] = None,
+    num_training_steps: Optional[int] = None,
+):
+    """
+    Unified API to get any scheduler from its name.
+
+    Args:
+        name (`str` or `SchedulerType`):
+            The name of the scheduler to use.
+        optimizer (`torch.optim.Optimizer`):
+            The optimizer that will be used during training.
+        num_warmup_steps (`int`, *optional*):
+            The number of warmup steps to do. This is not required by all schedulers (hence the argument being
+            optional), the function will raise an error if it's unset and the scheduler type requires it.
+        num_training_steps (`int``, *optional*):
+            The number of training steps to do. This is not required by all schedulers (hence the argument being
+            optional), the function will raise an error if it's unset and the scheduler type requires it.
+    """
+    name = SchedulerType(name)
+    schedule_func = TYPE_TO_SCHEDULER_FUNCTION[name]
+    if name == SchedulerType.CONSTANT:
+        return schedule_func(optimizer)
+
+    # All other schedulers require `num_warmup_steps`
+    if num_warmup_steps is None:
+        raise ValueError(f"{name} requires `num_warmup_steps`, please provide that argument.")
+
+    if name == SchedulerType.CONSTANT_WITH_WARMUP:
+        return schedule_func(optimizer, num_warmup_steps=num_warmup_steps)
+
+    # All other schedulers require `num_training_steps`
+    if num_training_steps is None:
+        raise ValueError(f"{name} requires `num_training_steps`, please provide that argument.")
+
+    return schedule_func(optimizer, num_warmup_steps=num_warmup_steps, num_training_steps=num_training_steps)
\ No newline at end of file