[Retiarii] Nest `ValueChoice` in `LayerChoice` and dict/list in `ValueChoice` (#3508)

nni/retiarii/converter/graph_gen.py

@@ -6,7 +6,7 @@ import re
 import torch
 
 from ..graph import Graph, Model, Node
-from ..nn.pytorch import InputChoice, LayerChoice, Placeholder
+from ..nn.pytorch import InputChoice, Placeholder
 from ..operation import Cell, Operation
 from ..serializer import get_init_parameters_or_fail
 from ..utils import get_importable_name
@@ -343,7 +343,7 @@ class GraphConverter:
                         subcell = ir_graph.add_node(submodule_full_name, submodule_type_str, sub_m_attrs)
                         if isinstance(submodule_obj, Placeholder):
                             subcell.update_label(submodule_obj.label)
-                        elif isinstance(submodule_obj, (LayerChoice, InputChoice)):
+                        elif isinstance(submodule_obj, InputChoice):
                             subcell.update_label(sub_m_attrs['label'])
                     else:
                         # Graph already created, create Cell for it
@@ -536,16 +536,6 @@ class GraphConverter:
         self.remove_unconnected_nodes(ir_graph, targeted_type='prim::GetAttr')
         self.merge_aten_slices(ir_graph)
 
-    def _handle_layerchoice(self, module):
-        choices = []
-        for cand in list(module):
-            cand_type = '__torch__.' + get_importable_name(cand.__class__)
-            choices.append({'type': cand_type, 'parameters': get_init_parameters_or_fail(cand)})
-        return {
-            'candidates': choices,
-            'label': module.label
-        }
-
     def _handle_inputchoice(self, module):
         return {
             'n_candidates': module.n_candidates,
@@ -557,7 +547,8 @@ class GraphConverter:
     def _handle_valuechoice(self, module):
         return {
             'candidates': module.candidates,
-            'label': module.label
+            'label': module.label,
+            'accessor': module._accessor
         }
 
     def convert_module(self, script_module, module, module_name, ir_model):
@@ -590,7 +581,13 @@ class GraphConverter:
         if original_type_name in MODULE_EXCEPT_LIST:
             pass  # do nothing
         elif original_type_name == OpTypeName.LayerChoice:
-            m_attrs = self._handle_layerchoice(module)
+            graph = Graph(ir_model, -100, module_name, _internal=True)  # graph_id is not used now
+            candidate_name_list = [f'layerchoice_{module.label}_{cand_name}' for cand_name in module.names]
+            for cand_name, cand in zip(candidate_name_list, module):
+                cand_type = '__torch__.' + get_importable_name(cand.__class__)
+                graph.add_node(cand_name, cand_type, get_init_parameters_or_fail(cand))
+            graph._register()
+            return graph, {'mutation': 'layerchoice', 'label': module.label, 'candidates': candidate_name_list}
         elif original_type_name == OpTypeName.InputChoice:
             m_attrs = self._handle_inputchoice(module)
         elif original_type_name == OpTypeName.ValueChoice:

nni/retiarii/graph.py

@@ -144,15 +144,17 @@ class Model:
         for graph_name, graph_data in ir.items():
             if graph_name != '_evaluator':
                 Graph._load(model, graph_name, graph_data)._register()
-        model.evaluator = Evaluator._load_with_type(ir['_evaluator']['__type__'], ir['_evaluator'])
+        if '_evaluator' in ir:
+            model.evaluator = Evaluator._load_with_type(ir['_evaluator']['__type__'], ir['_evaluator'])
         return model
 
     def _dump(self) -> Any:
         ret = {name: graph._dump() for name, graph in self.graphs.items()}
-        ret['_evaluator'] = {
-            '__type__': get_importable_name(self.evaluator.__class__),
-            **self.evaluator._dump()
-        }
+        if self.evaluator is not None:
+            ret['_evaluator'] = {
+                '__type__': get_importable_name(self.evaluator.__class__),
+                **self.evaluator._dump()
+            }
         return ret
 
     def get_nodes(self) -> Iterable['Node']:

nni/retiarii/nn/pytorch/api.py

 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
 
+import copy
+import warnings
 from collections import OrderedDict
 from typing import Any, List, Union, Dict
-import warnings
 
 import torch
 import torch.nn as nn
@@ -268,6 +269,7 @@ class ValueChoice(Translatable, nn.Module):
         super().__init__()
         self.candidates = candidates
         self._label = label if label is not None else f'valuechoice_{uid()}'
+        self._accessor = []
 
     @property
     def label(self):
@@ -279,11 +281,36 @@ class ValueChoice(Translatable, nn.Module):
 
     def _translate(self):
         # Will function as a value when used in serializer.
-        return self.candidates[0]
+        return self.access(self.candidates[0])
 
     def __repr__(self):
         return f'ValueChoice({self.candidates}, label={repr(self.label)})'
 
+    def access(self, value):
+        if not self._accessor:
+            return value
+        try:
+            v = value
+            for a in self._accessor:
+                v = v[a]
+        except KeyError:
+            raise KeyError(''.join([f'[{a}]' for a in self._accessor]) + f' does not work on {value}')
+        return v
+
+    def __getitem__(self, item):
+        """
+        Get a sub-element of value choice.
+
+        The underlying implementation is to clone the current instance, and append item to "accessor", which records all
+        the history getitem calls. For example, when accessor is ``[a, b, c]``, the value choice will return ``vc[a][b][c]``
+        where ``vc`` is the original value choice.
+        """
+        access = copy.deepcopy(self)
+        access._accessor.append(item)
+        for candidate in self.candidates:
+            access.access(candidate)
+        return access
+
 
 @basic_unit
 class Placeholder(nn.Module):

nni/retiarii/nn/pytorch/mutator.py

@@ -4,7 +4,7 @@
 from typing import Any, List, Optional, Tuple
 
 from ...mutator import Mutator
-from ...graph import Model, Node
+from ...graph import Cell, Model, Node
 from .api import ValueChoice
 
 
@@ -14,13 +14,23 @@ class LayerChoiceMutator(Mutator):
         self.nodes = nodes
 
     def mutate(self, model):
-        n_candidates = len(self.nodes[0].operation.parameters['candidates'])
-        indices = list(range(n_candidates))
-        chosen_index = self.choice(indices)
+        candidates = self.nodes[0].operation.parameters['candidates']
+        chosen = self.choice(candidates)
         for node in self.nodes:
-            target = model.get_node_by_name(node.name)
-            chosen_cand = node.operation.parameters['candidates'][chosen_index]
-            target.update_operation(chosen_cand['type'], chosen_cand['parameters'])
+            # Each layer choice corresponds to a cell, which is unconnected in the base graph.
+            # We add the connections here in the mutation logic.
+            # Thus, the mutated model should not be mutated again. Everything should be based on the original base graph.
+            target = model.graphs[node.operation.cell_name]
+            chosen_node = target.get_node_by_name(chosen)
+            assert chosen_node is not None
+            target.add_edge((target.input_node, 0), (chosen_node, None))
+            target.add_edge((chosen_node, None), (target.output_node, None))
+            model.get_node_by_name(node.name).update_operation(Cell(node.operation.cell_name))
+
+            # remove redundant nodes
+            for rm_node in target.hidden_nodes:
+                if rm_node.name != chosen_node.name:
+                    rm_node.remove()
 
 
 class InputChoiceMutator(Mutator):
@@ -61,20 +71,14 @@ class ParameterChoiceMutator(Mutator):
     def mutate(self, model):
         chosen = self.choice(self.candidates)
         for node, argname in self.nodes:
+            chosen_value = node.operation.parameters[argname].access(chosen)
             target = model.get_node_by_name(node.name)
-            target.update_operation(target.operation.type, {**target.operation.parameters, argname: chosen})
+            target.update_operation(target.operation.type, {**target.operation.parameters, argname: chosen_value})
 
 
 def process_inline_mutation(model: Model) -> Optional[List[Mutator]]:
     applied_mutators = []
 
-    lc_nodes = _group_by_label(model.get_nodes_by_type('__torch__.nni.retiarii.nn.pytorch.api.LayerChoice'))
-    for node_list in lc_nodes:
-        assert _is_all_equal(map(lambda node: len(node.operation.parameters['candidates']), node_list)), \
-            'Layer choice with the same label must have the same number of candidates.'
-        mutator = LayerChoiceMutator(node_list)
-        applied_mutators.append(mutator)
-
     ic_nodes = _group_by_label(model.get_nodes_by_type('__torch__.nni.retiarii.nn.pytorch.api.InputChoice'))
     for node_list in ic_nodes:
         assert _is_all_equal(map(lambda node: node.operation.parameters['n_candidates'], node_list)) and \
@@ -99,9 +103,20 @@ def process_inline_mutation(model: Model) -> Optional[List[Mutator]]:
     for node_list in pc_nodes:
         assert _is_all_equal([node.operation.parameters[name].candidates for node, name in node_list]), \
             'Value choice with the same label must have the same candidates.'
-        mutator = ParameterChoiceMutator(node_list, node_list[0][0].operation.parameters[node_list[0][1]].candidates)
+        first_node, first_argname = node_list[0]
+        mutator = ParameterChoiceMutator(node_list, first_node.operation.parameters[first_argname].candidates)
         applied_mutators.append(mutator)
 
+    # apply layer choice at last as it will delete some nodes
+    lc_nodes = _group_by_label(filter(lambda d: d.operation.parameters.get('mutation') == 'layerchoice',
+                                      model.get_nodes_by_type('_cell')))
+    for node_list in lc_nodes:
+        assert _is_all_equal(map(lambda node: len(node.operation.parameters['candidates']), node_list)), \
+            'Layer choice with the same label must have the same number of candidates.'
+        mutator = LayerChoiceMutator(node_list)
+        applied_mutators.append(mutator)
+
+
     if applied_mutators:
         return applied_mutators
     return None

nni/retiarii/operation_def/torch_op_def.py

@@ -69,6 +69,9 @@ class PrimConstant(PyTorchOperation):
         elif self.parameters['type'] == 'Device':
             value = self.parameters['value']
             return f'{output} = torch.device("{value}")'
+        elif self.parameters['type'] in ('dict', 'list', 'tuple'):
+            # TODO: prim::TupleIndex is not supported yet
+            return f'{output} = {repr(self.parameters["value"])}'
         else:
             raise RuntimeError(f'unsupported type of prim::Constant: {self.parameters["type"]}')
 

test/ut/retiarii/test_highlevel_apis.py

 import random
 import unittest
+from collections import Counter
 
 import nni.retiarii.nn.pytorch as nn
 import torch
@@ -252,6 +253,30 @@ class TestHighLevelAPI(unittest.TestCase):
         self.assertEqual(self._get_converted_pytorch_model(model1)(torch.randn(1, 3, 3, 3)).size(), torch.Size([1, 3, 3, 3]))
         self.assertAlmostEqual(self._get_converted_pytorch_model(model2)(torch.randn(1, 3, 3, 3)).abs().sum().item(), 0)
 
+    def test_value_choice_in_layer_choice(self):
+        class Net(nn.Module):
+            def __init__(self):
+                super().__init__()
+                self.linear = nn.LayerChoice([
+                    nn.Linear(3, nn.ValueChoice([10, 20])),
+                    nn.Linear(3, nn.ValueChoice([30, 40]))
+                ])
+
+            def forward(self, x):
+                return self.linear(x)
+
+        model = self._convert_to_ir(Net())
+        mutators = process_inline_mutation(model)
+        self.assertEqual(len(mutators), 3)
+        sz_counter = Counter()
+        sampler = RandomSampler()
+        for i in range(100):
+            model_new = model
+            for mutator in mutators:
+                model_new = mutator.bind_sampler(sampler).apply(model_new)
+            sz_counter[self._get_converted_pytorch_model(model_new)(torch.randn(1, 3)).size(1)] += 1
+        self.assertEqual(len(sz_counter), 4)
+
     def test_shared(self):
         class Net(nn.Module):
             def __init__(self, shared=True):
@@ -284,12 +309,94 @@ class TestHighLevelAPI(unittest.TestCase):
         # repeat test. Expectation: sometimes succeeds, sometimes fails.
         failed_count = 0
         for i in range(30):
+            model_new = model
             for mutator in mutators:
-                model = mutator.bind_sampler(sampler).apply(model)
+                model_new = mutator.bind_sampler(sampler).apply(model_new)
             self.assertEqual(sampler.counter, 2 * (i + 1))
             try:
-                self._get_converted_pytorch_model(model)(torch.randn(1, 3, 3, 3))
+                self._get_converted_pytorch_model(model_new)(torch.randn(1, 3, 3, 3))
             except RuntimeError:
                 failed_count += 1
         self.assertGreater(failed_count, 0)
         self.assertLess(failed_count, 30)
+
+    def test_valuechoice_access(self):
+        class Net(nn.Module):
+            def __init__(self):
+                super().__init__()
+                vc = nn.ValueChoice([(6, 3), (8, 5)])
+                self.conv = nn.Conv2d(3, vc[0], kernel_size=vc[1])
+
+            def forward(self, x):
+                return self.conv(x)
+
+        model = self._convert_to_ir(Net())
+        mutators = process_inline_mutation(model)
+        self.assertEqual(len(mutators), 1)
+        mutators[0].bind_sampler(EnumerateSampler())
+        input = torch.randn(1, 3, 5, 5)
+        self.assertEqual(self._get_converted_pytorch_model(mutators[0].apply(model))(input).size(),
+                         torch.Size([1, 6, 3, 3]))
+        self.assertEqual(self._get_converted_pytorch_model(mutators[0].apply(model))(input).size(),
+                         torch.Size([1, 8, 1, 1]))
+
+        class Net2(nn.Module):
+            def __init__(self):
+                super().__init__()
+                choices = [
+                    {'b': [3], 'bp': [6]},
+                    {'b': [6], 'bp': [12]}
+                ]
+                self.conv = nn.Conv2d(3, nn.ValueChoice(choices, label='a')['b'][0], 1)
+                self.conv1 = nn.Conv2d(nn.ValueChoice(choices, label='a')['bp'][0], 3, 1)
+
+            def forward(self, x):
+                x = self.conv(x)
+                return self.conv1(torch.cat((x, x), 1))
+
+        model = self._convert_to_ir(Net2())
+        mutators = process_inline_mutation(model)
+        self.assertEqual(len(mutators), 1)
+        mutators[0].bind_sampler(EnumerateSampler())
+        input = torch.randn(1, 3, 5, 5)
+        self._get_converted_pytorch_model(mutators[0].apply(model))(input)
+
+    def test_valuechoice_access_functional(self):
+        class Net(nn.Module):
+            def __init__(self):
+                super().__init__()
+                self.dropout_rate = nn.ValueChoice([[0.,], [1.,]])
+
+            def forward(self, x):
+                return F.dropout(x, self.dropout_rate()[0])
+
+        model = self._convert_to_ir(Net())
+        mutators = process_inline_mutation(model)
+        self.assertEqual(len(mutators), 1)
+        mutator = mutators[0].bind_sampler(EnumerateSampler())
+        model1 = mutator.apply(model)
+        model2 = mutator.apply(model)
+        self._get_converted_pytorch_model(model1)(torch.randn(1, 3, 3, 3))
+        self.assertEqual(self._get_converted_pytorch_model(model1)(torch.randn(1, 3, 3, 3)).size(), torch.Size([1, 3, 3, 3]))
+        self.assertAlmostEqual(self._get_converted_pytorch_model(model2)(torch.randn(1, 3, 3, 3)).abs().sum().item(), 0)
+
+    def test_valuechoice_access_functional_expression(self):
+        class Net(nn.Module):
+            def __init__(self):
+                super().__init__()
+                self.dropout_rate = nn.ValueChoice([[1.05,], [1.1,]])
+
+            def forward(self, x):
+                # if expression failed, the exception would be:
+                # ValueError: dropout probability has to be between 0 and 1, but got 1.05
+                return F.dropout(x, self.dropout_rate()[0] - .1)
+
+        model = self._convert_to_ir(Net())
+        mutators = process_inline_mutation(model)
+        self.assertEqual(len(mutators), 1)
+        mutator = mutators[0].bind_sampler(EnumerateSampler())
+        model1 = mutator.apply(model)
+        model2 = mutator.apply(model)
+        self._get_converted_pytorch_model(model1)(torch.randn(1, 3, 3, 3))
+        self.assertEqual(self._get_converted_pytorch_model(model1)(torch.randn(1, 3, 3, 3)).size(), torch.Size([1, 3, 3, 3]))
+        self.assertAlmostEqual(self._get_converted_pytorch_model(model2)(torch.randn(1, 3, 3, 3)).abs().sum().item(), 0)

test/ut/retiarii/test_strategy.py

@@ -62,11 +62,11 @@ class Net(nn.Module):
         self.fc1 = nn.LayerChoice([
             nn.Linear(4*4*50, hidden_size, bias=True),
             nn.Linear(4*4*50, hidden_size, bias=False)
-        ])
+        ], label='fc1')
         self.fc2 = nn.LayerChoice([
             nn.Linear(hidden_size, 10, bias=False),
             nn.Linear(hidden_size, 10, bias=True)
-        ])
+        ], label='fc2')
 
     def forward(self, x):
         x = F.relu(self.conv1(x))
@@ -97,8 +97,8 @@ def test_grid_search():
     selection = set()
     for model in engine.models:
         selection.add((
-            model.get_node_by_name('_model__fc1').operation.parameters['bias'],
-            model.get_node_by_name('_model__fc2').operation.parameters['bias']
+            model.graphs['_model__fc1'].hidden_nodes[0].operation.parameters['bias'],
+            model.graphs['_model__fc2'].hidden_nodes[0].operation.parameters['bias']
         ))
     assert len(selection) == 4
     _reset_execution_engine()
@@ -113,8 +113,8 @@ def test_random_search():
     selection = set()
     for model in engine.models:
         selection.add((
-            model.get_node_by_name('_model__fc1').operation.parameters['bias'],
-            model.get_node_by_name('_model__fc2').operation.parameters['bias']
+            model.graphs['_model__fc1'].hidden_nodes[0].operation.parameters['bias'],
+            model.graphs['_model__fc2'].hidden_nodes[0].operation.parameters['bias']
         ))
     assert len(selection) == 4
     _reset_execution_engine()