[Example] cluster-gat for ogb (#1875)

* cluster-gat for ogb

* Fix new graph

* Inference using minibatch style

* update readme

* Update params
Co-authored-by: Ubuntu <ubuntu@ip-172-31-34-186.ec2.internal>
Co-authored-by: Zihao Ye <expye@outlook.com>

examples/pytorch/ogb/cluster-gat/README.md

+# ClusterGAT 
+Params: 1540848
+
+## OGB Products
+Run `main.py` and you should directly see the result.
+
+Valid over 10 runs: 0.8985 ± 0.00224
+Accuracy over 10 runs: 0.79232 ± 0.007786 

examples/pytorch/ogb/cluster-gat/main.py

+import dgl
+from functools import partial
+import numpy as np
+import torch as th
+import torch.nn as nn
+import torch.nn.functional as F
+import torch.optim as optim
+import torch.multiprocessing as mp
+from torch.utils.data import DataLoader
+import dgl.function as fn
+import dgl.nn.pytorch as dglnn
+import time
+import argparse
+from _thread import start_new_thread
+from functools import wraps
+from dgl.data import RedditDataset
+import tqdm
+import traceback
+from ogb.nodeproppred import DglNodePropPredDataset
+
+from sampler import ClusterIter, subgraph_collate_fn
+
+#### Neighbor sampler
+
+
+class GAT(nn.Module):
+    def __init__(self,
+                 in_feats,
+                 num_heads,
+                 n_hidden,
+                 n_classes,
+                 n_layers,
+                 activation,
+                 dropout=0.):
+        super().__init__()
+        self.n_layers = n_layers
+        self.n_hidden = n_hidden
+        self.n_classes = n_classes
+        self.layers = nn.ModuleList()
+        self.num_heads = num_heads
+        self.layers.append(dglnn.GATConv(in_feats,
+                                         n_hidden,
+                                         num_heads=num_heads,
+                                         feat_drop=dropout,
+                                         attn_drop=dropout,
+                                         activation=activation,
+                                         negative_slope=0.2))
+        for i in range(1, n_layers - 1):
+            self.layers.append(dglnn.GATConv(n_hidden * num_heads,
+                                             n_hidden,
+                                             num_heads=num_heads,
+                                             feat_drop=dropout,
+                                             attn_drop=dropout,
+                                             activation=activation,
+                                             negative_slope=0.2))
+        self.layers.append(dglnn.GATConv(n_hidden * num_heads,
+                                         n_classes,
+                                         num_heads=num_heads,
+                                         feat_drop=dropout,
+                                         attn_drop=dropout,
+                                         activation=None,
+                                         negative_slope=0.2))
+
+    def forward(self, g, x):
+        h = x
+        for l, conv in enumerate(self.layers):
+            h = conv(g, h)
+            if l < len(self.layers) - 1:
+                h = h.flatten(1)
+        h = h.mean(1)
+        return h.log_softmax(dim=-1)
+
+    def inference(self, g, x, batch_size, device):
+        """
+        Inference with the GAT model on full neighbors (i.e. without neighbor sampling).
+        g : the entire graph.
+        x : the input of entire node set.
+        The inference code is written in a fashion that it could handle any number of nodes and
+        layers.
+        """
+        num_heads = self.num_heads
+        nodes = th.arange(g.number_of_nodes())
+        for l, layer in enumerate(self.layers):
+            if l < self.n_layers - 1:
+                y = th.zeros(g.number_of_nodes(), self.n_hidden * num_heads if l != len(self.layers) - 1 else self.n_classes)
+            else:
+                y = th.zeros(g.number_of_nodes(), self.n_hidden if l != len(self.layers) - 1 else self.n_classes)
+            sampler = dgl.sampling.MultiLayerNeighborSampler([None])
+            dataloader = dgl.sampling.NodeDataLoader(
+                    g,
+                    th.arange(g.number_of_nodes()),
+                    sampler,
+                    batch_size=batch_size,
+                    shuffle=False,
+                    drop_last=False,
+                    num_workers=args.num_workers)
+
+            layer.fc_src = layer.fc
+            layer.fc_dst = layer.fc
+            for input_nodes, output_nodes, blocks in tqdm.tqdm(dataloader):
+                block = blocks[0].to(device)
+                h = x[input_nodes].to(device)
+                h_dst = h[:block.number_of_dst_nodes()].to(device)
+                if l < self.n_layers - 1:
+                   h = layer(block, (h, h_dst)).flatten(1)
+                else:
+                    h = layer(block, (h, h_dst))
+                    h = h.mean(1)
+                    h = h.log_softmax(dim=-1)
+
+                y[output_nodes] = h.cpu()
+            x = y
+        return y
+
+def compute_acc(pred, labels):
+    """
+    Compute the accuracy of prediction given the labels.
+    """
+    return (th.argmax(pred, dim=1) == labels).float().sum() / len(pred)
+
+def evaluate(model, g, labels, val_nid, test_nid, batch_size, device):
+    """
+    Evaluate the model on the validation set specified by ``val_mask``.
+    g : The entire graph.
+    inputs : The features of all the nodes.
+    labels : The labels of all the nodes.
+    val_mask : A 0-1 mask indicating which nodes do we actually compute the accuracy for.
+    batch_size : Number of nodes to compute at the same time.
+    device : The GPU device to evaluate on.
+    """
+    model.eval()
+    with th.no_grad():
+        inputs = g.ndata['feat']
+        pred = model.inference(g, inputs, batch_size, device)
+    model.train()
+    return compute_acc(pred[val_nid], labels[val_nid]), compute_acc(pred[test_nid], labels[test_nid]), pred
+
+def model_param_summary(model):
+    """ Count the model parameters """
+    cnt = sum(p.numel() for p in model.parameters() if p.requires_grad)
+    print("Total Params {}".format(cnt))
+
+#### Entry point
+def run(args, device, data):
+    # Unpack data
+    train_nid, val_nid, test_nid, in_feats, labels, n_classes, g, cluster_iterator = data
+
+
+    # Define model and optimizer
+    model = GAT(in_feats, args.num_heads, args.num_hidden, n_classes, args.num_layers, F.relu, args.dropout)
+    model_param_summary(model)
+    model = model.to(device)
+    optimizer = optim.Adam(model.parameters(), lr=args.lr, weight_decay=args.wd)
+
+    # Training loop
+    avg = 0
+    best_eval_acc = 0
+    best_test_acc = 0
+    for epoch in range(args.num_epochs):
+        iter_load = 0
+        iter_far = 0
+        iter_back = 0
+        tic = time.time()
+
+        # Loop over the dataloader to sample the computation dependency graph as a list of
+        # blocks.
+        tic_start = time.time()
+        for step, cluster in enumerate(cluster_iterator):
+            cluster = cluster.to(device)
+            mask = cluster.ndata['train_mask']
+            if mask.sum() == 0:
+                continue
+            feat = cluster.ndata['feat']
+            batch_labels = cluster.ndata['labels']
+            tic_step = time.time()
+
+            # Compute loss and prediction
+            batch_pred = model(cluster, feat)
+            batch_pred = batch_pred[mask]
+            batch_labels = batch_labels[mask]
+            loss = nn.functional.nll_loss(batch_pred, batch_labels)
+            optimizer.zero_grad()
+            tic_far = time.time()
+            loss.backward()
+            optimizer.step()
+            tic_back = time.time()
+            iter_load += (tic_step - tic_start)
+            iter_far += (tic_far - tic_step)
+            iter_back += (tic_back - tic_far)
+
+            if step % args.log_every == 0:
+                acc = compute_acc(batch_pred, batch_labels)
+                gpu_mem_alloc = th.cuda.max_memory_allocated() / 1000000 if th.cuda.is_available() else 0
+                print('Epoch {:05d} | Step {:05d} | Loss {:.4f} | Train Acc {:.4f} | GPU {:.1f} MiB'.format(
+                    epoch, step, loss.item(), acc.item(), gpu_mem_alloc))
+                tic_start = time.time()
+
+        toc = time.time()
+        print('Epoch Time(s): {:.4f} Load {:.4f} Forward {:.4f} Backward {:.4f}'.format(toc - tic, iter_load, iter_far, iter_back))
+        if epoch >= 5:
+            avg += toc - tic
+
+        if epoch % args.eval_every == 0 and epoch != 0:
+            eval_acc, test_acc, pred = evaluate(model, g, labels, val_nid, test_nid, args.val_batch_size, device)
+            model = model.to(device)
+            if args.save_pred:
+                np.savetxt(args.save_pred + '%02d' % epoch, pred.argmax(1).cpu().numpy(), '%d')
+            print('Eval Acc {:.4f}'.format(eval_acc))
+            if eval_acc > best_eval_acc:
+                best_eval_acc = eval_acc
+                best_test_acc = test_acc
+            print('Best Eval Acc {:.4f} Test Acc {:.4f}'.format(best_eval_acc, best_test_acc))
+    print('Avg epoch time: {}'.format(avg / (epoch - 4)))
+    return best_test_acc
+
+if __name__ == '__main__':
+    argparser = argparse.ArgumentParser("multi-gpu training")
+    argparser.add_argument('--gpu', type=int, default=0,
+            help="GPU device ID. Use -1 for CPU training")
+    argparser.add_argument('--num-epochs', type=int, default=20)
+    argparser.add_argument('--num-hidden', type=int, default=128)
+    argparser.add_argument('--num-layers', type=int, default=3)
+    argparser.add_argument('--num-heads', type=int, default=8)
+    argparser.add_argument('--batch-size', type=int, default=32)
+    argparser.add_argument('--val-batch-size', type=int, default=2000)
+    argparser.add_argument('--log-every', type=int, default=20)
+    argparser.add_argument('--eval-every', type=int, default=1)
+    argparser.add_argument('--lr', type=float, default=0.001)
+    argparser.add_argument('--dropout', type=float, default=0.5)
+    argparser.add_argument('--save-pred', type=str, default='')
+    argparser.add_argument('--wd', type=float, default=0)
+    argparser.add_argument('--num_partitions', type=int, default=15000)
+    argparser.add_argument('--num-workers', type=int, default=0)
+    args = argparser.parse_args()
+
+    if args.gpu >= 0:
+        device = th.device('cuda:%d' % args.gpu)
+    else:
+        device = th.device('cpu')
+
+    # load reddit data
+    data = DglNodePropPredDataset(name='ogbn-products')
+    splitted_idx = data.get_idx_split()
+    train_idx, val_idx, test_idx = splitted_idx['train'], splitted_idx['valid'], splitted_idx['test']
+    graph, labels = data[0]
+    labels = labels[:, 0]
+    print('Total edges before adding self-loop {}'.format(graph.number_of_edges()))
+    graph = dgl.remove_self_loop(graph)
+    graph = dgl.add_self_loop(graph)
+    print('Total edges after adding self-loop {}'.format(graph.number_of_edges()))
+    num_nodes = train_idx.shape[0] + val_idx.shape[0] + test_idx.shape[0]
+    assert num_nodes == graph.number_of_nodes()
+    graph.ndata['labels'] = labels
+    mask = th.zeros(num_nodes, dtype=th.bool)
+    mask[train_idx] = True
+    graph.ndata['train_mask'] = mask
+    mask = th.zeros(num_nodes, dtype=th.bool)
+    mask[val_idx] = True
+    graph.ndata['valid_mask'] = mask
+    mask = th.zeros(num_nodes, dtype=th.bool)
+    mask[test_idx] = True
+    graph.ndata['test_mask'] = mask
+
+    graph.in_degrees(0)
+    graph.out_degrees(0)
+    graph.find_edges(0)
+
+    cluster_iter_data = ClusterIter(
+            'ogbn-products', graph, args.num_partitions, args.batch_size)
+    cluster_iterator = DataLoader(cluster_iter_data, batch_size=args.batch_size, shuffle=True, pin_memory=True, num_workers=0, collate_fn=partial(subgraph_collate_fn, graph))
+
+    in_feats = graph.ndata['feat'].shape[1]
+    n_classes = (labels.max() + 1).item()
+    # Pack data
+    data = train_idx, val_idx, test_idx, in_feats, labels, n_classes, graph, cluster_iterator
+
+    # Run 10 times
+    test_accs = []
+    for i in range(10):
+        test_accs.append(run(args, device, data))
+        print('Average test accuracy:', np.mean(test_accs), '±', np.std(test_accs))

examples/pytorch/ogb/cluster-gat/partition_utils.py

+from time import time
+
+import numpy as np
+
+import dgl
+from dgl.transform import metis_partition
+from dgl import backend as F
+
+def get_partition_list(g, psize):
+    p_gs = metis_partition(g, psize)
+    graphs = []
+    for k, val in p_gs.items():
+        nids = val.ndata[dgl.NID]
+        nids = F.asnumpy(nids)
+        graphs.append(nids)
+    return graphs

examples/pytorch/ogb/cluster-gat/sampler.py

+import os
+import random
+
+import dgl.function as fn
+import torch
+import time
+
+from partition_utils import *
+
+class ClusterIter(object):
+    '''The partition sampler given a DGLGraph and partition number.
+    The metis is used as the graph partition backend.
+    '''
+    def __init__(self, dn, g, psize, batch_size):
+        """Initialize the sampler.
+
+        Paramters
+        ---------
+        dn : str
+            The dataset name.
+        g  : DGLGraph
+            The full graph of dataset
+        psize: int
+            The partition number
+        batch_size: int
+            The number of partitions in one batch
+        """
+        self.psize = psize
+        self.batch_size = batch_size
+        # cache the partitions of known datasets&partition number
+        if dn:
+            fn = os.path.join('./datasets/', dn + '_{}.npy'.format(psize))
+            if os.path.exists(fn):
+                self.par_li = np.load(fn, allow_pickle=True)
+            else:
+                os.makedirs('./datasets/', exist_ok=True)
+                self.par_li = get_partition_list(g, psize)
+                np.save(fn, self.par_li)
+        else:
+            self.par_li = get_partition_list(g, psize)
+        par_list = []
+        for p in self.par_li:
+            par = torch.Tensor(p)
+            par_list.append(par)
+        self.par_list = par_list
+
+    def __len__(self):
+        return self.psize
+
+    def __getitem__(self, idx):
+        return self.par_li[idx]
+
+def subgraph_collate_fn(g, batch):
+    nids = np.concatenate(batch).reshape(-1).astype(np.int64)
+    g1 = g.subgraph(nids)
+    g1 = dgl.remove_self_loop(g1)
+    g1 = dgl.add_self_loop(g1)
+    return g1