flatten.h

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 * to you under the Apache License, Version 2.0 (the
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 *
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#ifndef TVM_TOPI_NN_FLATTEN_H_
#define TVM_TOPI_NN_FLATTEN_H_

#include <tvm/te/operation.h>
#include <tvm/topi/detail/constant_utils.h>
#include <tvm/topi/tags.h>

#include <string>
#include <vector>

namespace tvm {
namespace topi {
namespace nn {

using namespace tvm::te;

inline Tensor flatten(const Tensor& x, std::string name = "tensor", std::string tag = kInjective) {
  auto ishape = x->shape;
  PrimExpr dim = 1;
  for (size_t i = 1; i < ishape.size(); ++i) {
    dim = dim * ishape[i];
  }

  Array<PrimExpr> oshape({ishape[0], dim});

  std::vector<PrimExpr> extra_shape;
  for (size_t i = 1; i < ishape.size(); ++i) {
    extra_shape.push_back(ishape[i]);
  }
  std::reverse(extra_shape.begin(), extra_shape.end());

  return tvm::te::compute(
      oshape,
      [&](Var i, Var j) {
        PrimExpr idx = j;
        std::vector<PrimExpr> index;
        for (auto s : extra_shape) {
          index.push_back(indexmod(idx, s));
          idx = indexdiv(idx, s);
        }
        index.push_back(i);
        std::reverse(index.begin(), index.end());
        return x(index);
      },
      name, tag);
}

}  // namespace nn
}  // namespace topi
}  // namespace tvm
#endif  // TVM_TOPI_NN_FLATTEN_H_