text: /* Copyright (c) 2021 PaddlePaddle 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 "paddle/fluid/inference/tensorrt/convert/op_converter.h"
  
  namespace paddle {
  namespace framework {
  class Scope;
  namespace proto {
  class OpDesc;
  }  // namespace proto
  }  // namespace framework
  }  // namespace paddle
  
  namespace paddle {
  namespace inference {
  namespace tensorrt {
  
  /*
   * FlattenOp, only support static shape mode currently.
   */
  class FlattenOpConverter : public OpConverter {
   public:
    void operator()(const framework::proto::OpDesc& op,
                    const framework::Scope& scope, bool test_mode) override {
      framework::OpDesc op_desc(op, nullptr);
      // Declare inputs
      auto* input = engine_->GetITensor(op_desc.Input("X")[0]);
      int dims = input->getDimensions().nbDims;
      nvinfer1::IShuffleLayer* layer = nullptr;
      if (!engine_->with_dynamic_shape()) {
        int dim_prod = 1;
        for (int i = 0; i < dims; i++) {
          int dim_i = input->getDimensions().d[i];
          PADDLE_ENFORCE_GT(
              dim_i, 0,
              platform::errors::InvalidArgument(
                  "flatten input dim should be > 0, but got %d.", dim_i));
          dim_prod *= dim_i;
        }
        nvinfer1::Dims flatten_dim;
        flatten_dim.nbDims = 1;
        flatten_dim.d[0] = dim_prod;
        layer = TRT_ENGINE_ADD_LAYER(engine_, Shuffle, *input);
        layer->setReshapeDimensions(flatten_dim);
      } else {
        nvinfer1::Dims flatten_dim;
        flatten_dim.nbDims = 2;
        flatten_dim.d[0] = 0;
        flatten_dim.d[1] = -1;
        layer = TRT_ENGINE_ADD_LAYER(engine_, Shuffle, *input);
        layer->setReshapeDimensions(flatten_dim);
      }
      auto output_name = op_desc.Output("Out")[0];
      RreplenishLayerAndOutput(layer, "flatten", {output_name}, test_mode);
    }
  };
  
  }  // namespace tensorrt
  }  // namespace inference
  }  // namespace paddle
  
  REGISTER_TRT_OP_CONVERTER(flatten, FlattenOpConverter);
  