Remove identity - Keras (sony#1047)

* Add remove identety substitution for Keras.
* Use 'common' function in Pytorch substitution to avoid code duplication.

---------

Co-authored-by: reuvenp <reuvenp@altair-semi.com>

model_compression_toolkit/core/common/substitutions/remove_identity.py

@@ -0,0 +1,48 @@
+# Copyright 2024 Sony Semiconductor Israel, Inc. All rights reserved.
+#
+# 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.
+# ==============================================================================
+
+from model_compression_toolkit.core.common.graph.base_graph import Graph
+from model_compression_toolkit.core.common.graph.base_node import BaseNode
+
+
+def remove_identity_node(graph: Graph,
+                         node: BaseNode) -> Graph:
+    """
+    The method to perform the substitution of the identity node by
+    reconnecting its input directly to its output, effectively removing the node
+    from the graph.
+
+    Args:
+        graph: The current graph of operations where the node resides.
+        node: The specific `BaseNode` that is matched to be an Identity operation.
+
+    Returns:
+        Graph: The updated graph after removing the identity node.
+    """
+    # Retrieve the predecessor nodes of the identity node.
+    prev_identity_nodes = graph.get_prev_nodes(node)
+    # Ensure there is exactly one predecessor; otherwise, do nothing.
+    if len(prev_identity_nodes) != 1:
+        return graph
+
+    # Reconnect the output edges of the identity node to its predecessor,
+    # effectively bypassing the identity node.
+    graph.reconnect_out_edges(current_node=node, new_node=prev_identity_nodes[0])
+    # Remove the edge from the predecessor to the identity node.
+    graph.remove_edge(prev_identity_nodes[0], node)
+    # Remove the identity node from the graph.
+    graph.remove_node(node_to_remove=node)
+
+    return graph

model_compression_toolkit/core/keras/graph_substitutions/substitutions/remove_identity.py

@@ -0,0 +1,51 @@
+# Copyright 2024 Sony Semiconductor Israel, Inc. All rights reserved.
+#
+# 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 keras
+import tensorflow as tf
+
+from model_compression_toolkit.core.common.graph.graph_matchers import NodeOperationMatcher
+from model_compression_toolkit.core import common
+from model_compression_toolkit.core.common.graph.base_graph import Graph
+from model_compression_toolkit.core.common.graph.base_node import BaseNode
+from model_compression_toolkit.core.common.substitutions.remove_identity import remove_identity_node
+
+
+class RemoveIdentity(common.BaseSubstitution):
+    """
+    Remove Identity layers from the graph.
+    """
+
+    def __init__(self):
+        nodes = NodeOperationMatcher(keras.layers.Identity) | NodeOperationMatcher(tf.identity)
+        super().__init__(matcher_instance=nodes)
+
+    def substitute(self,
+                   graph: Graph,
+                   node: BaseNode) -> Graph:
+        """
+        The method to perform the substitution of the identity keras node by
+        reconnecting its input directly to its output, effectively removing the node
+        from the graph.
+
+        Args:
+            graph: The current graph of operations where the node resides.
+            node: The specific `BaseNode` that is matched to be an Identity operation.
+
+        Returns:
+            Graph: The updated graph after removing the identity node.
+        """
+        return remove_identity_node(graph, node)
+

model_compression_toolkit/core/keras/keras_implementation.py

@@ -22,6 +22,7 @@
 
 from model_compression_toolkit.constants import HESSIAN_NUM_ITERATIONS
 from model_compression_toolkit.core.common.hessian import TraceHessianRequest, HessianMode, HessianInfoService
+from model_compression_toolkit.core.keras.graph_substitutions.substitutions.remove_identity import RemoveIdentity
 from model_compression_toolkit.core.keras.hessian.activation_trace_hessian_calculator_keras import \
     ActivationTraceHessianCalculatorKeras
 from model_compression_toolkit.core.keras.hessian.weights_trace_hessian_calculator_keras import WeightsTraceHessianCalculatorKeras
@@ -246,7 +247,8 @@ def get_substitutions_prepare_graph(self, fw_info: FrameworkInfo = None) -> List
                 MatmulToDenseSubstitution(),
                 MultiHeadAttentionDecomposition(),
                 ActivationDecomposition(),
-                DwconvToConv()]
+                DwconvToConv(),
+                RemoveIdentity()]
 
     def get_substitutions_pre_statistics_collection(self, quant_config: QuantizationConfig) -> \
             List[common.BaseSubstitution]:

model_compression_toolkit/core/pytorch/graph_substitutions/substitutions/remove_identity.py

@@ -12,15 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 # ==============================================================================
-from torch import reshape
 import torch
 
-from model_compression_toolkit.logger import Logger
+from model_compression_toolkit.core.common.substitutions.remove_identity import remove_identity_node
 from model_compression_toolkit.core.common.graph.graph_matchers import NodeOperationMatcher
 from model_compression_toolkit.core import common
 from model_compression_toolkit.core.common.graph.base_graph import Graph
 from model_compression_toolkit.core.common.graph.base_node import BaseNode
-from model_compression_toolkit.core.pytorch.constants import BATCH_DIM_VALUE
 
 
 class RemoveIdentity(common.BaseSubstitution):
@@ -47,20 +45,6 @@ def substitute(self,
         Returns:
             Graph: The updated graph after removing the identity node.
         """
+        return remove_identity_node(graph, node)
 
-        # Retrieve the predecessor nodes of the identity node.
-        prev_identity_nodes = graph.get_prev_nodes(node)
-        # Ensure there is exactly one predecessor; otherwise, do nothing.
-        if len(prev_identity_nodes) != 1:
-            return graph
-
-        # Reconnect the output edges of the identity node to its predecessor,
-        # effectively bypassing the identity node.
-        graph.reconnect_out_edges(current_node=node, new_node=prev_identity_nodes[0])
-        # Remove the edge from the predecessor to the identity node.
-        graph.remove_edge(prev_identity_nodes[0], node)
-        # Remove the identity node from the graph.
-        graph.remove_node(node_to_remove=node)
-
-        return graph
 

tests/keras_tests/feature_networks_tests/feature_networks/remove_identity_test.py

@@ -0,0 +1,35 @@
+# Copyright 2024 Sony Semiconductor Israel, Inc. All rights reserved.
+#
+# 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.
+# ==============================================================================
+from tests.keras_tests.feature_networks_tests.base_keras_feature_test import BaseKerasFeatureNetworkTest
+import keras
+import tensorflow as tf
+
+class RemoveIdentityTest(BaseKerasFeatureNetworkTest):
+    def __init__(self, unit_test):
+        super().__init__(unit_test)
+
+    def create_networks(self):
+        inputs = keras.layers.Input(shape=self.get_input_shapes()[0][1:])
+        x = keras.layers.Conv2D(3, 3)(inputs)
+        x = keras.layers.Identity()(x)
+        x = tf.identity(x)
+        outputs = keras.layers.BatchNormalization()(x)
+        return keras.Model(inputs=inputs, outputs=outputs)
+
+    def compare(self, quantized_model, float_model, input_x=None, quantization_info=None):
+        # Make sure identity and bn layers are not in the final model.
+        # there should be 4 layers: input, input_quantizer, conv, conv_quantizer
+        self.unit_test.assertTrue(len(quantized_model.layers)==4)
+

tests/keras_tests/feature_networks_tests/test_features_runner.py

@@ -99,6 +99,7 @@
     QuantizationAwareTrainingQuantizerHolderTest
 from tests.keras_tests.feature_networks_tests.feature_networks.relu_replacement_test import ReluReplacementTest, \
     SingleReluReplacementTest, ReluReplacementWithAddBiasTest
+from tests.keras_tests.feature_networks_tests.feature_networks.remove_identity_test import RemoveIdentityTest
 from tests.keras_tests.feature_networks_tests.feature_networks.residual_collapsing_test import ResidualCollapsingTest1, \
     ResidualCollapsingTest2
 from tests.keras_tests.feature_networks_tests.feature_networks.reused_layer_mixed_precision_test import \
@@ -139,7 +140,10 @@
 
 
 class FeatureNetworkTest(unittest.TestCase):
-
+
+    def test_remove_identity(self):
+        RemoveIdentityTest(self).run_test()
+
     def test_per_tensor_weight_quantization(self):
         PerTensorWeightQuantizationTest(self).run_test()