Files
composable_kernel/include/ck_tile/host/reference/reference_reduce.hpp
yashagar f515d29036 General 2D Reduction Kernel
* Move the reduction kernel from the example
* Split the code and add the necessary policy, problem, shape files as
per ck_tile convention
* Add/modify the headers
* Modified the example to work with the 'new' kernel
* Added tests for the kernel
* N-D refernce reduce
* Added support for N-D input with transform to 2D
* Added padding to support various input sized tensors
* Bug fix in the thread buffer constructor
* Some comments to explain the reduce2d block kernel
2025-07-22 14:29:55 +03:00

90 lines
3.1 KiB
C++

// SPDX-License-Identifier: MIT
// Copyright (c) 2018-2023, Advanced Micro Devices, Inc. All rights reserved.
#pragma once
#include "ck_tile/core.hpp"
#include "ck_tile/host/host_tensor.hpp"
#include <thread>
namespace ck_tile {
template <typename XDataType, typename ComputeDataType, typename YDataType, typename ReduceOp>
CK_TILE_HOST void
reference_reduce(const HostTensor<XDataType>& x_m_n, HostTensor<YDataType>& y_m, ReduceOp reduce_op)
{
auto f = [&](auto m) {
const int N = x_m_n.mDesc.get_lengths()[1];
ComputeDataType v_acc = reduce_op.template GetIdentityValue<ComputeDataType>();
for(int n = 0; n < N; ++n)
{
const ComputeDataType v_a = type_convert<ComputeDataType>(x_m_n(m, n));
v_acc = reduce_op(v_acc, v_a);
}
y_m(m) = ck_tile::type_convert<YDataType>(v_acc);
};
make_ParallelTensorFunctor(f, y_m.mDesc.get_lengths()[0])(std::thread::hardware_concurrency());
}
// Generic reference reduce for arbitrary dimensions
template <typename XDataType,
typename ComputeDataType,
typename YDataType,
typename ReduceOp,
typename KeptDim,
typename ReduceDims>
CK_TILE_HOST void reference_reduce(const HostTensor<XDataType>& x_tensor,
HostTensor<YDataType>& y_tensor,
ReduceOp reduce_op,
KeptDim kept_dim,
ReduceDims reduce_dims)
{
const auto& x_lengths = x_tensor.mDesc.get_lengths();
const auto kept_len = x_lengths[kept_dim.at(0)];
// Calculate total reduce elements
index_t total_reduce_elements = 1;
static_for<0, reduce_dims.size(), 1>{}(
[&](auto i) { total_reduce_elements *= x_lengths[reduce_dims.at(i)]; });
auto f = [&](auto kept_idx) {
ComputeDataType v_acc = reduce_op.template GetIdentityValue<ComputeDataType>();
for(index_t reduce_idx = 0; reduce_idx < total_reduce_elements; ++reduce_idx)
{
// Convert linear index to multi-dimensional indices
std::vector<index_t> indices(x_lengths.size(), 0);
indices[kept_dim.at(0)] = kept_idx;
index_t temp = reduce_idx;
static_for<0, reduce_dims.size(), 1>{}([&](auto i) {
constexpr auto dim = reduce_dims.at(reduce_dims.size() - 1 - i);
const auto len = x_lengths[dim];
indices[dim] = temp % len;
temp /= len;
});
// Flat tensor access
index_t flat_idx = 0;
const auto& strides = x_tensor.mDesc.get_strides();
for(size_t d = 0; d < indices.size(); ++d)
{
flat_idx += indices[d] * strides[d];
}
const auto v_a = type_convert<ComputeDataType>(x_tensor.mData[flat_idx]);
v_acc = reduce_op(v_acc, v_a);
}
y_tensor(kept_idx) = type_convert<YDataType>(v_acc);
};
make_ParallelTensorFunctor(f, kept_len)(std::thread::hardware_concurrency());
}
} // namespace ck_tile