1 files changed, 69 insertions, 0 deletions
diff --git a/tensorflow/contrib/lite/toco/graph_transformations/create_im2col_arrays.cc b/tensorflow/contrib/lite/toco/graph_transformations/create_im2col_arrays.cc
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index 0000000000..1735b51e5b
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+++ b/tensorflow/contrib/lite/toco/graph_transformations/create_im2col_arrays.cc
@@ -0,0 +1,69 @@
+/* Copyright 2017 The TensorFlow Authors. 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.
+==============================================================================*/
+#include <memory>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "absl/strings/str_cat.h"
+#include "tensorflow/contrib/lite/toco/graph_transformations/graph_transformations.h"
+#include "tensorflow/contrib/lite/toco/model.h"
+#include "tensorflow/contrib/lite/toco/tooling_util.h"
+#include "tensorflow/core/platform/logging.h"
+
+namespace toco {
+
+bool CreateIm2colArrays::Run(Model* model, std::size_t op_index) {
+  auto conv_it = model->operators.begin() + op_index;
+  if (conv_it->get()->type != OperatorType::kConv) {
+    return false;
+  }
+  auto* conv_op = static_cast<ConvOperator*>(conv_it->get());
+  if (conv_op->outputs.size() == 2) {
+    // We already have an im2col array
+    return false;
+  }
+  const auto& weights_array = *model->arrays[conv_op->inputs[1]];
+  if (!weights_array.has_shape()) {
+    // We need to yield until weights dims have been resolved, because
+    // from the weights dims we determine whether an im2col array is
+    // needed.
+    return false;
+  }
+  const auto& weights_shape = weights_array.shape();
+  const int kheight = weights_shape.dims(1);
+  const int kwidth = weights_shape.dims(2);
+  if (kwidth == 1 && kheight == 1 && conv_op->stride_width == 1 &&
+      conv_op->stride_height == 1) {
+    // 1x1 unstrided conv does not need an im2col array.
+    return false;
+  }
+
+  // Create the im2col array.
+  CHECK_EQ(conv_op->outputs.size(), 1);
+  const string& im2col_array_name =
+      AvailableArrayName(*model, conv_op->inputs[0] + "_im2col");
+  model->GetOrCreateArray(im2col_array_name);
+  conv_op->outputs.push_back(im2col_array_name);
+  AddMessageF(
+      "Created an im2col array for %s, with %dx%d kernel and stride_width=%d, "
+      "stride_height=%d",
+      LogName(*conv_op), kwidth, kheight, conv_op->stride_width,
+      conv_op->stride_height);
+
+  return true;
+}
+
+}  // namespace toco