Implementation of ctc beam search decoder op in custom op fashion.

PiperOrigin-RevId: 207210333

1 files changed, 29 insertions, 0 deletions

diff --git a/tensorflow/contrib/lite/toco/import_tensorflow.cc b/tensorflow/contrib/lite/toco/import_tensorflow.cc
index 9a3db5c888..9a404c2606 100644
--- a/tensorflow/contrib/lite/toco/import_tensorflow.cc
+++ b/tensorflow/contrib/lite/toco/import_tensorflow.cc
@@ -1854,6 +1854,34 @@ tensorflow::Status ConvertOneHotOperator(
   return tensorflow::Status::OK();
 }
 
+tensorflow::Status ConvertCTCBeamSearchDecoderOperator(
+    const NodeDef& node, const TensorFlowImportFlags& tf_import_flags,
+    Model* model) {
+  CHECK_EQ(node.op(), "CTCBeamSearchDecoder");
+  TF_QCHECK_OK(CheckInputsCount(node, tf_import_flags, 2));
+
+  auto* op = new CTCBeamSearchDecoderOperator;
+  for (const string& input : node.input()) {
+    op->inputs.push_back(input);
+  }
+
+  op->beam_width =
+      HasAttr(node, "beam_width") ? GetIntAttr(node, "beam_width") : 1;
+  op->top_paths =
+      HasAttr(node, "top_paths") ? GetIntAttr(node, "top_paths") : 1;
+  op->merge_repeated = HasAttr(node, "merge_repeated")
+                           ? GetBoolAttr(node, "merge_repeated")
+                           : true;
+
+  // There are top_paths + 1 outputs.
+  op->outputs.push_back(node.name());  // Implicit :0.
+  for (int i = 0; i < op->top_paths; ++i) {
+    op->outputs.push_back(node.name() + ":" + std::to_string(i + 1));
+  }
+  model->operators.emplace_back(op);
+  return tensorflow::Status::OK();
+}
+
 }  // namespace
 
 namespace internal {
@@ -1888,6 +1916,7 @@ ConverterMapType GetTensorFlowNodeConverterMap() {
       {"Const", ConvertConstOperator},
       {"Conv2D", ConvertConvOperator},
       {"Conv2DBackpropInput", ConvertTransposeConvOperator},
+      {"CTCBeamSearchDecoder", ConvertCTCBeamSearchDecoderOperator},
       {"DepthToSpace", ConvertDepthToSpaceOperator},
       {"DepthwiseConv2dNative", ConvertDepthwiseConvOperator},
       {"Div", ConvertSimpleOperator<DivOperator, 2>},