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/** Common algorithms on (hierarchical) tensors */

#pragma once

#include <cute/config.hpp>

#include <cute/tensor.hpp>

namespace cute
{

//
// for_each
//

template <class Engine, class Layout, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
for_each(Tensor<Engine,Layout> const& tensor, UnaryOp&& op)
{
  CUTE_UNROLL
  for (int i = 0; i < size(tensor); ++i) {
    static_cast<UnaryOp&&>(op)(tensor(i));
  }
}

template <class Engine, class Layout, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
for_each(Tensor<Engine,Layout>& tensor, UnaryOp&& op)
{
  CUTE_UNROLL
  for (int i = 0; i < size(tensor); ++i) {
    static_cast<UnaryOp&&>(op)(tensor(i));
  }
}

// Accept mutable temporaries
template <class Engine, class Layout, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
for_each(Tensor<Engine,Layout>&& tensor, UnaryOp&& op)
{
  return for_each(tensor, static_cast<UnaryOp&&>(op));
}

//
// transform
//

// Similar to std::transform but does not return number of elements affected
template <class Engine, class Layout, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<Engine,Layout>& tensor, UnaryOp&& op)
{
  CUTE_UNROLL
  for (int i = 0; i < size(tensor); ++i) {
    tensor(i) = static_cast<UnaryOp&&>(op)(tensor(i));
  }
}

// Accept mutable temporaries
template <class Engine, class Layout, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<Engine,Layout>&& tensor, UnaryOp&& op)
{
  return transform(tensor, std::forward<UnaryOp>(op));
}

// Similar to std::transform transforms one tensors and assigns it to another
template <class EngineIn, class LayoutIn, class EngineOut, class LayoutOut, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<EngineIn,LayoutIn>& tensor_in, Tensor<EngineOut,LayoutOut>& tensor_out, UnaryOp&& op)
{
  CUTE_UNROLL
  for (int i = 0; i < size(tensor_in); ++i) {
    tensor_out(i) = static_cast<UnaryOp&&>(op)(tensor_in(i));
  }
}

// Accept mutable temporaries
template <class EngineIn, class LayoutIn,
          class EngineOut, class LayoutOut, class UnaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<EngineIn,LayoutIn>&& tensor_in, Tensor<EngineOut,LayoutOut>&& tensor_out, UnaryOp&& op)
{
  return transform(tensor_in, tensor_out, op);
}

// Similar to std::transform with a binary operation
// Takes two tensors as input and one tensor as output. 
// Applies the binary_op to tensor_in1 and tensor_in2 and
// assigns it to tensor_out
template <class EngineIn1, class LayoutIn1,
          class EngineIn2, class LayoutIn2,
          class EngineOut, class LayoutOut, class BinaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<EngineIn1,LayoutIn1>& tensor_in1,
          Tensor<EngineIn2,LayoutIn2>& tensor_in2,
          Tensor<EngineOut,LayoutOut>& tensor_out, 
          BinaryOp&& op)
{
  CUTE_UNROLL
  for (int i = 0; i < size(tensor_in1); ++i) {
    tensor_out(i) = static_cast<BinaryOp&&>(op)(tensor_in1(i), tensor_in2(i));
  }
}

// Accept mutable temporaries
template <class EngineIn1, class LayoutIn1,
          class EngineIn2, class LayoutIn2,
          class EngineOut, class LayoutOut, class BinaryOp>
CUTE_HOST_DEVICE constexpr
void
transform(Tensor<EngineIn1,LayoutIn1>&& tensor_in1, 
          Tensor<EngineIn2,LayoutIn2>&& tensor_in2,
          Tensor<EngineOut,LayoutOut>&& tensor_out,
          BinaryOp&& op)
{
  return transform(tensor_in1, tensor_in2, tensor_out, op);
}

} // end namespace cute