Fix layer choice on IT and deprecate "choices" and "length" (#2386)

src/sdk/pynni/nni/nas/pytorch/classic_nas/mutator.py

@@ -92,8 +92,8 @@ class ClassicMutator(Mutator):
             The list for corresponding search space.
         """
         # doesn't support multihot for layer choice yet
-        onehot_list = [False] * mutable.length
-        assert 0 <= idx < mutable.length and search_space_item[idx] == value, \
+        onehot_list = [False] * len(mutable)
+        assert 0 <= idx < len(mutable) and search_space_item[idx] == value, \
             "Index '{}' in search space '{}' is not '{}'".format(idx, search_space_item, value)
         onehot_list[idx] = True
         return torch.tensor(onehot_list, dtype=torch.bool)  # pylint: disable=not-callable

src/sdk/pynni/nni/nas/pytorch/darts/mutator.py

@@ -61,7 +61,7 @@ class DartsMutator(Mutator):
             if isinstance(mutable, LayerChoice):
                 max_val, index = torch.max(F.softmax(self.choices[mutable.key], dim=-1)[:-1], 0)
                 edges_max[mutable.key] = max_val
-                result[mutable.key] = F.one_hot(index, num_classes=mutable.length).view(-1).bool()
+                result[mutable.key] = F.one_hot(index, num_classes=len(mutable)).view(-1).bool()
         for mutable in self.mutables:
             if isinstance(mutable, InputChoice):
                 if mutable.n_chosen is not None:

src/sdk/pynni/nni/nas/pytorch/enas/mutator.py

@@ -86,15 +86,15 @@ class EnasMutator(Mutator):
         for mutable in self.mutables:
             if isinstance(mutable, LayerChoice):
                 if self.max_layer_choice == 0:
-                    self.max_layer_choice = mutable.length
-                assert self.max_layer_choice == mutable.length, \
+                    self.max_layer_choice = len(mutable)
+                assert self.max_layer_choice == len(mutable), \
                     "ENAS mutator requires all layer choice have the same number of candidates."
                 # We are judging by keys and module types to add biases to layer choices. Needs refactor.
                 if "reduce" in mutable.key:
                     def is_conv(choice):
                         return "conv" in str(type(choice)).lower()
                     bias = torch.tensor([self.branch_bias if is_conv(choice) else -self.branch_bias  # pylint: disable=not-callable
-                                         for choice in mutable.choices])
+                                         for choice in mutable])
                     self.bias_dict[mutable.key] = nn.Parameter(bias, requires_grad=False)
 
         self.embedding = nn.Embedding(self.max_layer_choice + 1, self.lstm_size)

src/sdk/pynni/nni/nas/pytorch/mutables.py

@@ -2,6 +2,7 @@
 # Licensed under the MIT license.
 
 import logging
+import warnings
 from collections import OrderedDict
 
 import torch.nn as nn
@@ -140,9 +141,12 @@ class LayerChoice(Mutable):
     Attributes
     ----------
     length : int
-        Number of ops to choose from.
-    names: list of str
+        Deprecated. Number of ops to choose from. ``len(layer_choice)`` is recommended.
+    names : list of str
         Names of candidates.
+    choices : list of Module
+        Deprecated. A list of all candidate modules in the layer choice module.
+        ``list(layer_choice)`` is recommended, which will serve the same purpose.
 
     Notes
     -----
@@ -156,30 +160,65 @@ class LayerChoice(Mutable):
             ("conv7x7", nn.Conv2d(7, 16, 128))
         ]))
 
+    Elements in layer choice can be modified or deleted. Use ``del self.op_choice["conv5x5"]`` or
+    ``self.op_choice[1] = nn.Conv3d(...)``. Adding more choices is not supported yet.
     """
 
     def __init__(self, op_candidates, reduction="sum", return_mask=False, key=None):
         super().__init__(key=key)
-        self.length = len(op_candidates)
-        self.choices = []
         self.names = []
         if isinstance(op_candidates, OrderedDict):
             for name, module in op_candidates.items():
                 assert name not in ["length", "reduction", "return_mask", "_key", "key", "names"], \
                     "Please don't use a reserved name '{}' for your module.".format(name)
                 self.add_module(name, module)
-                self.choices.append(module)
                 self.names.append(name)
         elif isinstance(op_candidates, list):
             for i, module in enumerate(op_candidates):
                 self.add_module(str(i), module)
-                self.choices.append(module)
                 self.names.append(str(i))
         else:
             raise TypeError("Unsupported op_candidates type: {}".format(type(op_candidates)))
         self.reduction = reduction
         self.return_mask = return_mask
 
+    def __getitem__(self, idx):
+        if isinstance(idx, str):
+            return self._modules[idx]
+        return list(self)[idx]
+
+    def __setitem__(self, idx, module):
+        key = idx if isinstance(idx, str) else self.names[idx]
+        return setattr(self, key, module)
+
+    def __delitem__(self, idx):
+        if isinstance(idx, slice):
+            for key in self.names[idx]:
+                delattr(self, key)
+        else:
+            if isinstance(idx, str):
+                key, idx = idx, self.names.index(idx)
+            else:
+                key = self.names[idx]
+            delattr(self, key)
+        del self.names[idx]
+
+    @property
+    def length(self):
+        warnings.warn("layer_choice.length is deprecated. Use `len(layer_choice)` instead.", DeprecationWarning)
+        return len(self)
+
+    def __len__(self):
+        return len(self.names)
+
+    def __iter__(self):
+        return map(lambda name: self._modules[name], self.names)
+
+    @property
+    def choices(self):
+        warnings.warn("layer_choice.choices is deprecated. Use `list(layer_choice)` instead.", DeprecationWarning)
+        return list(self)
+
     def forward(self, *args, **kwargs):
         """
         Returns

src/sdk/pynni/nni/nas/pytorch/mutator.py

@@ -150,16 +150,16 @@ class Mutator(BaseMutator):
         """
         if self._connect_all:
             return self._all_connect_tensor_reduction(mutable.reduction,
-                                                      [op(*args, **kwargs) for op in mutable.choices]), \
-                torch.ones(mutable.length)
+                                                      [op(*args, **kwargs) for op in mutable]), \
+                torch.ones(len(mutable))
 
         def _map_fn(op, args, kwargs):
             return op(*args, **kwargs)
 
         mask = self._get_decision(mutable)
-        assert len(mask) == len(mutable.choices), \
-            "Invalid mask, expected {} to be of length {}.".format(mask, len(mutable.choices))
-        out = self._select_with_mask(_map_fn, [(choice, args, kwargs) for choice in mutable.choices], mask)
+        assert len(mask) == len(mutable), \
+            "Invalid mask, expected {} to be of length {}.".format(mask, len(mutable))
+        out = self._select_with_mask(_map_fn, [(choice, args, kwargs) for choice in mutable], mask)
         return self._tensor_reduction(mutable.reduction, out), mask
 
     def on_forward_input_choice(self, mutable, tensor_list):

src/sdk/pynni/nni/nas/pytorch/pdarts/mutator.py

@@ -32,7 +32,7 @@ class PdartsMutator(DartsMutator):
         for mutable in self.mutables:
             if isinstance(mutable, LayerChoice):
 
-                switches = self.switches.get(mutable.key, [True for j in range(mutable.length)])
+                switches = self.switches.get(mutable.key, [True for j in range(len(mutable))])
                 choices = self.choices[mutable.key]
 
                 operations_count = np.sum(switches)
@@ -48,12 +48,12 @@ class PdartsMutator(DartsMutator):
             if isinstance(module, LayerChoice):
                 switches = self.switches.get(module.key)
                 choices = self.choices[module.key]
-                if len(module.choices) > len(choices):
+                if len(module) > len(choices):
                     # from last to first, so that it won't effect previous indexes after removed one.
                     for index in range(len(switches)-1, -1, -1):
                         if switches[index] == False:
-                            del(module.choices[index])
-                            module.length -= 1
+                            del module[index]
+                assert len(module) <= len(choices), "Failed to remove dropped choices."
 
     def sample_final(self):
         results = super().sample_final()

src/sdk/pynni/nni/nas/pytorch/proxylessnas/mutator.py

@@ -53,15 +53,15 @@ class MixedOp(nn.Module):
             A LayerChoice in user model
         """
         super(MixedOp, self).__init__()
-        self.ap_path_alpha = nn.Parameter(torch.Tensor(mutable.length))
-        self.ap_path_wb = nn.Parameter(torch.Tensor(mutable.length))
+        self.ap_path_alpha = nn.Parameter(torch.Tensor(len(mutable)))
+        self.ap_path_wb = nn.Parameter(torch.Tensor(len(mutable)))
         self.ap_path_alpha.requires_grad = False
         self.ap_path_wb.requires_grad = False
         self.active_index = [0]
         self.inactive_index = None
         self.log_prob = None
         self.current_prob_over_ops = None
-        self.n_choices = mutable.length
+        self.n_choices = len(mutable)
 
     def get_ap_path_alpha(self):
         return self.ap_path_alpha
@@ -120,8 +120,8 @@ class MixedOp(nn.Module):
                     return binary_grads
                 return backward
             output = ArchGradientFunction.apply(
-                x, self.ap_path_wb, run_function(mutable.key, mutable.choices, self.active_index[0]),
-                backward_function(mutable.key, mutable.choices, self.active_index[0], self.ap_path_wb))
+                x, self.ap_path_wb, run_function(mutable.key, list(mutable), self.active_index[0]),
+                backward_function(mutable.key, list(mutable), self.active_index[0], self.ap_path_wb))
         else:
             output = self.active_op(mutable)(x)
         return output
@@ -164,7 +164,7 @@ class MixedOp(nn.Module):
         PyTorch module
             the chosen operation
         """
-        return mutable.choices[self.active_index[0]]
+        return mutable[self.active_index[0]]
 
     @property
     def active_op_index(self):
@@ -222,12 +222,12 @@ class MixedOp(nn.Module):
             sample = torch.multinomial(probs, 1)[0].item()
             self.active_index = [sample]
             self.inactive_index = [_i for _i in range(0, sample)] + \
-                                [_i for _i in range(sample + 1, len(mutable.choices))]
+                                [_i for _i in range(sample + 1, len(mutable))]
             self.log_prob = torch.log(probs[sample])
             self.current_prob_over_ops = probs
             self.ap_path_wb.data[sample] = 1.0
         # avoid over-regularization
-        for choice in mutable.choices:
+        for choice in mutable:
             for _, param in choice.named_parameters():
                 param.grad = None
 
@@ -430,8 +430,8 @@ class ProxylessNasMutator(BaseMutator):
                 involved_index = mixed_op.active_index
             for i in range(mixed_op.n_choices):
                 if i not in involved_index:
-                    unused[i] = mutable.choices[i]
-                    mutable.choices[i] = None
+                    unused[i] = mutable[i]
+                    mutable[i] = None
             self._unused_modules.append(unused)
 
     def unused_modules_back(self):
@@ -442,7 +442,7 @@ class ProxylessNasMutator(BaseMutator):
             return
         for m, unused in zip(self.mutable_list, self._unused_modules):
             for i in unused:
-                m.choices[i] = unused[i]
+                m[i] = unused[i]
         self._unused_modules = None
 
     def arch_requires_grad(self):
@@ -474,5 +474,5 @@ class ProxylessNasMutator(BaseMutator):
             assert isinstance(mutable, LayerChoice)
             index, _ = mutable.registered_module.chosen_index
             # pylint: disable=not-callable
-            result[mutable.key] = F.one_hot(torch.tensor(index), num_classes=mutable.length).view(-1).bool()
+            result[mutable.key] = F.one_hot(torch.tensor(index), num_classes=len(mutable)).view(-1).bool()
         return result

src/sdk/pynni/nni/nas/pytorch/random/mutator.py

@@ -18,8 +18,8 @@ class RandomMutator(Mutator):
         result = dict()
         for mutable in self.mutables:
             if isinstance(mutable, LayerChoice):
-                gen_index = torch.randint(high=mutable.length, size=(1, ))
-                result[mutable.key] = F.one_hot(gen_index, num_classes=mutable.length).view(-1).bool()
+                gen_index = torch.randint(high=len(mutable), size=(1, ))
+                result[mutable.key] = F.one_hot(gen_index, num_classes=len(mutable)).view(-1).bool()
             elif isinstance(mutable, InputChoice):
                 if mutable.n_chosen is None:
                     result[mutable.key] = torch.randint(high=2, size=(mutable.n_candidates,)).view(-1).bool()

src/sdk/pynni/tests/models/pytorch_models/__init__.py

 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
 
+from .layer_choice_only import LayerChoiceOnlySearchSpace
 from .mutable_scope import SpaceWithMutableScope
 from .naive import NaiveSearchSpace
 from .nested import NestedSpace

src/sdk/pynni/tests/models/pytorch_models/layer_choice_only.py

+# Copyright (c) Microsoft Corporation.
+# Licensed under the MIT license.
+
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+
+from nni.nas.pytorch.mutables import LayerChoice
+
+
+class LayerChoiceOnlySearchSpace(nn.Module):
+    def __init__(self, test_case):
+        super().__init__()
+        self.test_case = test_case
+        self.conv1 = LayerChoice([nn.Conv2d(3, 6, 3, padding=1), nn.Conv2d(3, 6, 5, padding=2)])
+        self.pool = nn.MaxPool2d(2, 2)
+        self.conv2 = LayerChoice([nn.Conv2d(6, 16, 3, padding=1), nn.Conv2d(6, 16, 5, padding=2)],
+                                 return_mask=True)
+        self.conv3 = nn.Conv2d(16, 16, 1)
+        self.bn = nn.BatchNorm2d(16)
+
+        self.gap = nn.AdaptiveAvgPool2d(1)
+        self.fc = nn.Linear(16, 10)
+
+    def forward(self, x):
+        bs = x.size(0)
+
+        x = self.pool(F.relu(self.conv1(x)))
+        x0, mask = self.conv2(x)
+        self.test_case.assertEqual(mask.size(), torch.Size([2]))
+        x1 = F.relu(self.conv3(x0))
+
+        x = self.pool(self.bn(x1))
+        self.test_case.assertEqual(mask.size(), torch.Size([2]))
+
+        x = self.gap(x).view(bs, -1)
+        x = self.fc(x)
+        return x

src/sdk/pynni/tests/test_nas.py

@@ -3,6 +3,7 @@
 import importlib
 import os
 import sys
+from collections import OrderedDict
 from unittest import TestCase, main
 
 import torch
@@ -11,6 +12,7 @@ from nni.nas.pytorch.classic_nas import get_and_apply_next_architecture
 from nni.nas.pytorch.darts import DartsMutator
 from nni.nas.pytorch.enas import EnasMutator
 from nni.nas.pytorch.fixed import apply_fixed_architecture
+from nni.nas.pytorch.mutables import LayerChoice
 from nni.nas.pytorch.random import RandomMutator
 from nni.nas.pytorch.utils import _reset_global_mutable_counting
 
@@ -101,6 +103,43 @@ class NasTestCase(TestCase):
             get_and_apply_next_architecture(model)
             self.iterative_sample_and_forward(model)
 
+    def test_proxylessnas(self):
+        model = self.model_module.LayerChoiceOnlySearchSpace(self)
+        get_and_apply_next_architecture(model)
+        self.iterative_sample_and_forward(model)
+
+    def test_layer_choice(self):
+        for i in range(2):
+            for j in range(2):
+                if j == 0:
+                    # test number
+                    layer_choice = LayerChoice([nn.Conv2d(3, 3, 3), nn.Conv2d(3, 5, 3), nn.Conv2d(3, 6, 3)])
+                else:
+                    # test ordered dict
+                    layer_choice = LayerChoice(OrderedDict([
+                        ("conv1", nn.Conv2d(3, 3, 3)),
+                        ("conv2", nn.Conv2d(3, 5, 3)),
+                        ("conv3", nn.Conv2d(3, 6, 3))
+                    ]))
+                if i == 0:
+                    # test modify
+                    self.assertEqual(len(layer_choice.choices), 3)
+                    layer_choice[1] = nn.Conv2d(3, 4, 3)
+                    self.assertEqual(layer_choice[1].out_channels, 4)
+                    self.assertEqual(len(layer_choice[0:2]), 2)
+                    if j > 0:
+                        layer_choice["conv3"] = nn.Conv2d(3, 7, 3)
+                        self.assertEqual(layer_choice[-1].out_channels, 7)
+                if i == 1:
+                    # test delete
+                    del layer_choice[1]
+                    self.assertEqual(len(layer_choice), 2)
+                    self.assertEqual(len(list(layer_choice)), 2)
+                    self.assertEqual(layer_choice.names, ["conv1", "conv3"] if j > 0 else ["0", "2"])
+                    if j > 0:
+                        del layer_choice["conv1"]
+                        self.assertEqual(len(layer_choice), 1)
+
 
 if __name__ == '__main__':
     main()