text: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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.
   */
  
  /*!
   * \file index_copy-inl.h
   * \brief implementation of index_copy tensor operation
   */
  
  #ifndef MXNET_OPERATOR_CONTRIB_INDEX_COPY_INL_H_
  #define MXNET_OPERATOR_CONTRIB_INDEX_COPY_INL_H_
  
  #include <mxnet/operator_util.h>
  #include <vector>
  #include <limits>
  #include <algorithm>
  #include "../elemwise_op_common.h"
  #include "../mshadow_op.h"
  #include "../mxnet_op.h"
  #include "../tensor/init_op.h"
  
  namespace mxnet {
  namespace op {
  
  template<typename xpu>
  void IndexCopyForward(const nnvm::NodeAttrs& attrs,
                        const OpContext& ctx,
                        const std::vector<TBlob>& inputs,
                        const std::vector<OpReqType>& req,
                        const std::vector<TBlob>& outputs);
  
  template<typename xpu>
  void IndexCopyBackward(const nnvm::NodeAttrs& attrs,
                         const OpContext& ctx,
                         const std::vector<TBlob>& inputs,
                         const std::vector<OpReqType>& req,
                         const std::vector<TBlob>& outputs);
  
  inline bool IndexCopyShape(const nnvm::NodeAttrs& attrs,
                             mxnet::ShapeVector *in_attrs,
                             mxnet::ShapeVector *out_attrs) {
    // inputs[0]: original tensor
    // inputs[1]: index vector
    // inputs[2]: copied tensor
    CHECK_EQ(in_attrs->size(), 3U);
    // outputs[0]: a new tensor
    CHECK_EQ(out_attrs->size(), 1U);
    // inputs[1] must be a vector
    CHECK_EQ(in_attrs->at(1).ndim(), 1);
    // Shape matching
    CHECK_EQ(in_attrs->at(0).ndim(), in_attrs->at(2).ndim());
    for (int i = 0; i < in_attrs->at(0).ndim(); ++i) {
      if (i == 0) {
        CHECK_GE(in_attrs->at(0)[i], in_attrs->at(2)[i]);
      } else {
        CHECK_EQ(in_attrs->at(0)[i], in_attrs->at(2)[i]);
      }
    }
    // The the length of the first dim of copied tensor
    // must equal to the size of index vector
    CHECK_EQ(in_attrs->at(1)[0], in_attrs->at(2)[0]);
    SHAPE_ASSIGN_CHECK(*out_attrs, 0, in_attrs->at(0));
    SHAPE_ASSIGN_CHECK(*in_attrs, 0, out_attrs->at(0));
    return !mxnet::op::shape_is_none(out_attrs->at(0));
  }
  
  }  // namespace op
  }  // namespace mxnet
  
  #endif  // MXNET_OPERATOR_CONTRIB_INDEX_COPY_INL_H_
  