Extract controller from mutator to make offline decisions

examples/nas/.gitignore

@@ -1 +1,2 @@
-data
+data
+checkpoints

examples/nas/darts/model.py

@@ -2,7 +2,7 @@
 import torch.nn as nn
 
 import ops
-from nni.nas.pytorch import mutables, darts
+from nni.nas.pytorch import mutables
 
 
 class AuxiliaryHead(nn.Module):
@@ -31,12 +31,14 @@ def forward(self, x):
         return logits
 
 
-class Node(darts.DartsNode):
-    def __init__(self, node_id, num_prev_nodes, channels, num_downsample_connect, drop_path_prob=0.):
-        super().__init__(node_id, limitation=2)
+class Node(nn.Module):
+    def __init__(self, node_id, num_prev_nodes, channels, num_downsample_connect):
+        super().__init__()
         self.ops = nn.ModuleList()
+        choice_keys = []
         for i in range(num_prev_nodes):
             stride = 2 if i < num_downsample_connect else 1
+            choice_keys.append("{}_p{}".format(node_id, i))
             self.ops.append(
                 mutables.LayerChoice(
                     [
@@ -48,18 +50,19 @@ def __init__(self, node_id, num_prev_nodes, channels, num_downsample_connect, dr
                         ops.DilConv(channels, channels, 3, stride, 2, 2, affine=False),
                         ops.DilConv(channels, channels, 5, stride, 4, 2, affine=False),
                     ],
-                    key="{}_p{}".format(node_id, i)))
-        self.drop_path = ops.DropPath_(drop_path_prob)
+                    key=choice_keys[-1]))
+        self.drop_path = ops.DropPath_()
+        self.input_switch = mutables.InputChoice(choose_from=choice_keys, n_chosen=2, key="{}_switch".format(node_id))
 
     def forward(self, prev_nodes):
         assert len(self.ops) == len(prev_nodes)
         out = [op(node) for op, node in zip(self.ops, prev_nodes)]
-        return sum(self.drop_path(o) for o in out if o is not None)
+        return self.input_switch(out)
 
 
 class Cell(nn.Module):
 
-    def __init__(self, n_nodes, channels_pp, channels_p, channels, reduction_p, reduction, drop_path_prob=0.):
+    def __init__(self, n_nodes, channels_pp, channels_p, channels, reduction_p, reduction):
         super().__init__()
         self.reduction = reduction
         self.n_nodes = n_nodes
@@ -74,10 +77,9 @@ def __init__(self, n_nodes, channels_pp, channels_p, channels, reduction_p, redu
 
         # generate dag
         self.mutable_ops = nn.ModuleList()
-        for depth in range(self.n_nodes):
-            self.mutable_ops.append(Node("r{:d}_n{}".format(reduction, depth),
-                                         depth + 2, channels, 2 if reduction else 0,
-                                         drop_path_prob=drop_path_prob))
+        for depth in range(2, self.n_nodes + 2):
+            self.mutable_ops.append(Node("{}_n{}".format("reduce" if reduction else "normal", depth),
+                                         depth, channels, 2 if reduction else 0))
 
     def forward(self, s0, s1):
         # s0, s1 are the outputs of previous previous cell and previous cell, respectively.
@@ -93,7 +95,7 @@ def forward(self, s0, s1):
 class CNN(nn.Module):
 
     def __init__(self, input_size, in_channels, channels, n_classes, n_layers, n_nodes=4,
-                 stem_multiplier=3, auxiliary=False, drop_path_prob=0.):
+                 stem_multiplier=3, auxiliary=False):
         super().__init__()
         self.in_channels = in_channels
         self.channels = channels
@@ -120,7 +122,7 @@ def __init__(self, input_size, in_channels, channels, n_classes, n_layers, n_nod
                 c_cur *= 2
                 reduction = True
 
-            cell = Cell(n_nodes, channels_pp, channels_p, c_cur, reduction_p, reduction, drop_path_prob=drop_path_prob)
+            cell = Cell(n_nodes, channels_pp, channels_p, c_cur, reduction_p, reduction)
             self.cells.append(cell)
             c_cur_out = c_cur * n_nodes
             channels_pp, channels_p = channels_p, c_cur_out
@@ -147,3 +149,8 @@ def forward(self, x):
         if aux_logits is not None:
             return logits, aux_logits
         return logits
+
+    def drop_path_prob(self, p):
+        for module in self.modules():
+            if isinstance(module, ops.DropPath_):
+                module.p = p

examples/nas/darts/retrain.py

@@ -0,0 +1,143 @@
+import logging
+from argparse import ArgumentParser
+
+import torch
+import torch.nn as nn
+
+import datasets
+import utils
+from model import CNN
+from nni.nas.pytorch.fixed import apply_fixed_architecture
+from nni.nas.pytorch.utils import AverageMeter
+
+logging.basicConfig(level=logging.INFO)
+logger = logging.getLogger(__name__)
+device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
+
+
+def train(config, train_loader, model, optimizer, criterion, epoch):
+    top1 = AverageMeter("top1")
+    top5 = AverageMeter("top5")
+    losses = AverageMeter("losses")
+
+    cur_step = epoch * len(train_loader)
+    cur_lr = optimizer.param_groups[0]['lr']
+    logger.info("Epoch %d LR %.6f", epoch, cur_lr)
+
+    model.train()
+
+    for step, (x, y) in enumerate(train_loader):
+        x, y = x.to(device, non_blocking=True), y.to(device, non_blocking=True)
+        bs = x.size(0)
+
+        optimizer.zero_grad()
+        logits, aux_logits = model(x)
+        loss = criterion(logits, y)
+        if config.aux_weight > 0.:
+            loss += config.aux_weight * criterion(aux_logits, y)
+        loss.backward()
+        # gradient clipping
+        nn.utils.clip_grad_norm_(model.parameters(), config.grad_clip)
+        optimizer.step()
+
+        accuracy = utils.accuracy(logits, y, topk=(1, 5))
+        losses.update(loss.item(), bs)
+        top1.update(accuracy["acc1"], bs)
+        top5.update(accuracy["acc5"], bs)
+
+        if step % config.log_frequency == 0 or step == len(train_loader) - 1:
+            logger.info(
+                "Train: [{:3d}/{}] Step {:03d}/{:03d} Loss {losses.avg:.3f} "
+                "Prec@(1,5) ({top1.avg:.1%}, {top5.avg:.1%})".format(
+                    epoch + 1, config.epochs, step, len(train_loader) - 1, losses=losses,
+                    top1=top1, top5=top5))
+
+        cur_step += 1
+
+    logger.info("Train: [{:3d}/{}] Final Prec@1 {:.4%}".format(epoch + 1, config.epochs, top1.avg))
+
+
+def validate(config, valid_loader, model, criterion, epoch, cur_step):
+    top1 = AverageMeter("top1")
+    top5 = AverageMeter("top5")
+    losses = AverageMeter("losses")
+
+    model.eval()
+
+    with torch.no_grad():
+        for step, (X, y) in enumerate(valid_loader):
+            X, y = X.to(device, non_blocking=True), y.to(device, non_blocking=True)
+            N = X.size(0)
+
+            logits = model(X)
+            loss = criterion(logits, y)
+
+            accuracy = utils.accuracy(logits, y, topk=(1, 5))
+            losses.update(loss.item(), N)
+            top1.update(accuracy["acc1"], N)
+            top5.update(accuracy["acc5"], N)
+
+            if step % config.log_frequency == 0 or step == len(valid_loader) - 1:
+                logger.info(
+                    "Valid: [{:3d}/{}] Step {:03d}/{:03d} Loss {losses.avg:.3f} "
+                    "Prec@(1,5) ({top1.avg:.1%}, {top5.avg:.1%})".format(
+                        epoch + 1, config.epochs, step, len(valid_loader) - 1, losses=losses,
+                        top1=top1, top5=top5))
+
+    logger.info("Valid: [{:3d}/{}] Final Prec@1 {:.4%}".format(epoch + 1, config.epochs, top1.avg))
+
+    return top1.avg
+
+
+if __name__ == "__main__":
+    parser = ArgumentParser("darts")
+    parser.add_argument("--layers", default=20, type=int)
+    parser.add_argument("--batch-size", default=96, type=int)
+    parser.add_argument("--log-frequency", default=10, type=int)
+    parser.add_argument("--epochs", default=600, type=int)
+    parser.add_argument("--aux-weight", default=0.4, type=float)
+    parser.add_argument("--drop-path-prob", default=0.2, type=float)
+    parser.add_argument("--workers", default=4)
+    parser.add_argument("--grad-clip", default=5., type=float)
+    parser.add_argument("--arc-checkpoint", default="./checkpoints/epoch_0.json")
+
+    args = parser.parse_args()
+    dataset_train, dataset_valid = datasets.get_dataset("cifar10", cutout_length=16)
+
+    model = CNN(32, 3, 36, 10, args.layers, auxiliary=True)
+    apply_fixed_architecture(model, args.arc_checkpoint, device=device)
+    criterion = nn.CrossEntropyLoss()
+
+    model.to(device)
+    criterion.to(device)
+
+    optimizer = torch.optim.SGD(model.parameters(), 0.025, momentum=0.9, weight_decay=3.0E-4)
+    lr_scheduler = torch.optim.lr_scheduler.CosineAnnealingLR(optimizer, args.epochs, eta_min=1E-6)
+
+    train_loader = torch.utils.data.DataLoader(dataset_train,
+                                               batch_size=args.batch_size,
+                                               shuffle=True,
+                                               num_workers=args.workers,
+                                               pin_memory=True)
+    valid_loader = torch.utils.data.DataLoader(dataset_valid,
+                                               batch_size=args.batch_size,
+                                               shuffle=False,
+                                               num_workers=args.workers,
+                                               pin_memory=True)
+
+    best_top1 = 0.
+    for epoch in range(args.epochs):
+        drop_prob = args.drop_path_prob * epoch / args.epochs
+        model.drop_path_prob(drop_prob)
+
+        # training
+        train(args, train_loader, model, optimizer, criterion, epoch)
+
+        # validation
+        cur_step = (epoch + 1) * len(train_loader)
+        top1 = validate(args, valid_loader, model, criterion, epoch, cur_step)
+        best_top1 = max(best_top1, top1)
+
+        lr_scheduler.step()
+
+    logger.info("Final best Prec@1 = {:.4%}".format(best_top1))

examples/nas/darts/search.py

@@ -13,7 +13,7 @@
 if __name__ == "__main__":
     parser = ArgumentParser("darts")
     parser.add_argument("--layers", default=8, type=int)
-    parser.add_argument("--batch-size", default=96, type=int)
+    parser.add_argument("--batch-size", default=64, type=int)
     parser.add_argument("--log-frequency", default=10, type=int)
     parser.add_argument("--epochs", default=50, type=int)
     args = parser.parse_args()
@@ -36,4 +36,4 @@
                            batch_size=args.batch_size,
                            log_frequency=args.log_frequency,
                            callbacks=[LearningRateScheduler(lr_scheduler), ArchitectureCheckpoint("./checkpoints")])
-    trainer.train_and_validate()
+    trainer.train()

examples/nas/enas/macro.py

@@ -6,7 +6,7 @@
 
 class ENASLayer(mutables.MutableScope):
 
-    def __init__(self, key, num_prev_layers, in_filters, out_filters):
+    def __init__(self, key, prev_labels, in_filters, out_filters):
         super().__init__(key)
         self.in_filters = in_filters
         self.out_filters = out_filters
@@ -18,16 +18,16 @@ def __init__(self, key, num_prev_layers, in_filters, out_filters):
             PoolBranch('avg', in_filters, out_filters, 3, 1, 1),
             PoolBranch('max', in_filters, out_filters, 3, 1, 1)
         ])
-        if num_prev_layers > 0:
-            self.skipconnect = mutables.InputChoice(num_prev_layers, n_selected=None, reduction="sum")
+        if len(prev_labels) > 0:
+            self.skipconnect = mutables.InputChoice(choose_from=prev_labels, n_chosen=None, reduction="sum")
         else:
             self.skipconnect = None
         self.batch_norm = nn.BatchNorm2d(out_filters, affine=False)
 
-    def forward(self, prev_layers, prev_labels):
+    def forward(self, prev_layers):
         out = self.mutable(prev_layers[-1])
         if self.skipconnect is not None:
-            connection = self.skipconnect(prev_layers[:-1], tags=prev_labels)
+            connection = self.skipconnect(prev_layers[:-1])
             if connection is not None:
                 out += connection
         return self.batch_norm(out)
@@ -53,11 +53,12 @@ def __init__(self, num_layers=12, out_filters=24, in_channels=3, num_classes=10,
 
         self.layers = nn.ModuleList()
         self.pool_layers = nn.ModuleList()
+        labels = []
         for layer_id in range(self.num_layers):
+            labels.append("layer_{}".format(layer_id))
             if layer_id in self.pool_layers_idx:
                 self.pool_layers.append(FactorizedReduce(self.out_filters, self.out_filters))
-            self.layers.append(ENASLayer("layer_{}".format(layer_id), layer_id,
-                                         self.out_filters, self.out_filters))
+            self.layers.append(ENASLayer(labels[-1], labels[:-1], self.out_filters, self.out_filters))
 
         self.gap = nn.AdaptiveAvgPool2d(1)
         self.dense = nn.Linear(self.out_filters, self.num_classes)
@@ -66,12 +67,11 @@ def forward(self, x):
         bs = x.size(0)
         cur = self.stem(x)
 
-        layers, labels = [cur], []
+        layers = [cur]
 
         for layer_id in range(self.num_layers):
-            cur = self.layers[layer_id](layers, labels)
+            cur = self.layers[layer_id](layers)
             layers.append(cur)
-            labels.append(self.layers[layer_id].key)
             if layer_id in self.pool_layers_idx:
                 for i, layer in enumerate(layers):
                     layers[i] = self.pool_layers[self.pool_layers_idx.index(layer_id)](layer)

examples/nas/enas/micro.py

@@ -32,9 +32,9 @@ def forward(self, x):
 
 
 class Cell(nn.Module):
-    def __init__(self, cell_name, num_prev_layers, channels):
+    def __init__(self, cell_name, prev_labels, channels):
         super().__init__()
-        self.input_choice = mutables.InputChoice(num_prev_layers, n_selected=1, return_mask=True,
+        self.input_choice = mutables.InputChoice(choose_from=prev_labels, n_chosen=1, return_mask=True,
                                                  key=cell_name + "_input")
         self.op_choice = mutables.LayerChoice([
             SepConvBN(channels, channels, 3, 1),
@@ -44,21 +44,21 @@ def __init__(self, cell_name, num_prev_layers, channels):
             nn.Identity()
         ], key=cell_name + "_op")
 
-    def forward(self, prev_layers, prev_labels):
-        chosen_input, chosen_mask = self.input_choice(prev_layers, tags=prev_labels)
+    def forward(self, prev_layers):
+        chosen_input, chosen_mask = self.input_choice(prev_layers)
         cell_out = self.op_choice(chosen_input)
         return cell_out, chosen_mask
 
 
 class Node(mutables.MutableScope):
-    def __init__(self, node_name, num_prev_layers, channels):
+    def __init__(self, node_name, prev_node_names, channels):
         super().__init__(node_name)
-        self.cell_x = Cell(node_name + "_x", num_prev_layers, channels)
-        self.cell_y = Cell(node_name + "_y", num_prev_layers, channels)
+        self.cell_x = Cell(node_name + "_x", prev_node_names, channels)
+        self.cell_y = Cell(node_name + "_y", prev_node_names, channels)
 
-    def forward(self, prev_layers, prev_labels):
-        out_x, mask_x = self.cell_x(prev_layers, prev_labels)
-        out_y, mask_y = self.cell_y(prev_layers, prev_labels)
+    def forward(self, prev_layers):
+        out_x, mask_x = self.cell_x(prev_layers)
+        out_y, mask_y = self.cell_y(prev_layers)
         return out_x + out_y, mask_x | mask_y
 
 
@@ -93,8 +93,11 @@ def __init__(self, num_nodes, in_channels_pp, in_channels_p, out_channels, reduc
 
         self.num_nodes = num_nodes
         name_prefix = "reduce" if reduction else "normal"
-        self.nodes = nn.ModuleList([Node("{}_node_{}".format(name_prefix, i),
-                                         i + 2, out_channels) for i in range(num_nodes)])
+        self.nodes = nn.ModuleList()
+        node_labels = [mutables.InputChoice.NO_KEY, mutables.InputChoice.NO_KEY]
+        for i in range(num_nodes):
+            node_labels.append("{}_node_{}".format(name_prefix, i))
+            self.nodes.append(Node(node_labels[-1], node_labels[:-1], out_channels))
         self.final_conv_w = nn.Parameter(torch.zeros(out_channels, self.num_nodes + 2, out_channels, 1, 1), requires_grad=True)
         self.bn = nn.BatchNorm2d(out_channels, affine=False)
         self.reset_parameters()
@@ -106,14 +109,12 @@ def forward(self, pprev, prev):
         pprev_, prev_ = self.preproc0(pprev), self.preproc1(prev)    
 
         prev_nodes_out = [pprev_, prev_]
-        prev_nodes_labels = ["prev1", "prev2"]
         nodes_used_mask = torch.zeros(self.num_nodes + 2, dtype=torch.bool, device=prev.device)
         for i in range(self.num_nodes):
-            node_out, mask = self.nodes[i](prev_nodes_out, prev_nodes_labels)
+            node_out, mask = self.nodes[i](prev_nodes_out)
             nodes_used_mask[:mask.size(0)] |= mask
             prev_nodes_out.append(node_out)
-            prev_nodes_labels.append(self.nodes[i].key)
-
+
         unused_nodes = torch.cat([out for used, out in zip(nodes_used_mask, prev_nodes_out) if not used], 1)
         unused_nodes = F.relu(unused_nodes)
         conv_weight = self.final_conv_w[:, ~nodes_used_mask, :, :, :]