cutlass/tools/util/reference/host/gemm.h
2018-10-26 14:38:46 -07:00

225 lines
7.3 KiB
C++

/***************************************************************************************************
* Copyright (c) 2017-2018, NVIDIA CORPORATION. All rights reserved.
*
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* provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice, this list of
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*
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/*! \file
\brief Reference implementation for GEMM in host-side code.
*/
#pragma once
#include "cutlass/coord.h"
#include "cutlass/matrix_traits.h"
#include "cutlass/tensor_view.h"
#include "cutlass/gemm/gemm_coord.h"
#include "tools/util/reference/detail/inner_product.h"
namespace cutlass {
namespace reference {
namespace host {
////////////////////////////////////////////////////////////////////////////////////////////////////
/// Computes a general matrix product among matrices (tensors of rank=2) pointed to by TensorRef
/// objects.
///
/// Explicitly naming types needed by this template can be cumbersome, particularly for the
/// accumulator type, so a function argument 'initial_accum' is exposed. Passing
/// AccumulatorType(0) as the last function argument can be easier than naming all template
/// arguments explicitly.
template <
typename TensorRefA,
typename TensorRefB,
typename TensorRefC,
typename ScalarType,
typename AccumulatorType
>
void Gemm(
gemm::GemmCoord problem_size,
ScalarType alpha,
TensorRefA tensor_a,
TensorRefB tensor_b,
ScalarType beta,
TensorRefC tensor_c,
AccumulatorType initial_accum) {
typedef typename TensorRefA::Storage AType;
typedef typename TensorRefB::Storage BType;
typedef typename TensorRefC::Storage CType;
static_assert(
TensorRefA::kRank == 2 &&
TensorRefB::kRank == 2 &&
TensorRefC::kRank == 2, "Tensors must be of rank 2");
// Note: batch is ignored.
int const M = problem_size.m();
int const N = problem_size.n();
int const K = problem_size.k();
// Blocking necessary to speedup reference implementation
int const Mblock = 32;
int const Nblock = 32;
for (int row_block = 0; row_block < M; row_block += Mblock) {
for (int col_block = 0; col_block < N; col_block += Nblock) {
AccumulatorType accum[Mblock][Nblock];
for (int j = 0; j < Nblock; j++) {
for (int i = 0; i < Mblock; i++) {
accum[i][j] = initial_accum;
}
}
for (int k_block = 0; k_block < K; ++k_block) {
for (int j = 0; j < Nblock; j++) {
for (int i = 0; i < Mblock; i++) {
int row = row_block + i;
int col = col_block + j;
if (row < M && col < N) {
AType a = tensor_a.at(MatrixCoord(row, k_block));
BType b = tensor_b.at(MatrixCoord(k_block, col));
accum[i][j] = cutlass::reference::detail::inner_product(a, b, accum[i][j]);
}
}
}
}
for (int j = 0; j < Nblock; j++) {
for (int i = 0; i < Mblock; i++) {
int row = row_block + i;
int col = col_block + j;
MatrixCoord coord = MatrixCoord(row, col);
if (row < M && col < N) {
tensor_c.at(coord) = cutlass::reference::detail::Cast<ScalarType, CType>::apply(
alpha * ScalarType(accum[i][j]) +
beta * ScalarType(tensor_c.at(coord)));
}
}
}
}
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////
/// Computes a general matrix product among matrices (tensors of rank=2) pointed to by TensorRef
/// objects.
///
/// This assumes the accumulator type is the same type as the scalars.
template <
typename TensorRefA,
typename TensorRefB,
typename TensorRefC,
typename ScalarType
>
void Gemm(
gemm::GemmCoord problem_size,
ScalarType alpha,
TensorRefA tensor_a,
TensorRefB tensor_b,
ScalarType beta,
TensorRefC tensor_c) {
Gemm(problem_size, alpha, tensor_a, tensor_b, beta, tensor_c, ScalarType(0));
}
////////////////////////////////////////////////////////////////////////////////////////////////////
//
// Batched GEMM
//
////////////////////////////////////////////////////////////////////////////////////////////////////
/// Computes a batch of GEMMs over a set of matrices of common dimension.
//
// TensorRefCollection* is a type satisfying the TensorRefCollection concept.
//
template <
typename TensorRefCollectionA,
typename TensorRefCollectionB,
typename TensorRefCollectionC,
typename ScalarType,
typename AccumulatorType
>
void BatchedGemm(
gemm::GemmCoord problem_size,
ScalarType alpha,
TensorRefCollectionA const& tensor_a,
TensorRefCollectionB const& tensor_b,
ScalarType beta,
TensorRefCollectionC &tensor_c,
AccumulatorType initial_accum) {
typename TensorRefCollectionA::ConstIterator tensor_a_it = tensor_a.begin();
typename TensorRefCollectionB::ConstIterator tensor_b_it = tensor_b.begin();
typename TensorRefCollectionC::ConstIterator tensor_c_it = tensor_c.begin();
for (int batch = 0;
batch < problem_size.batch();
++batch, ++tensor_a_it, ++tensor_b_it, ++tensor_c_it) {
Gemm(
problem_size,
alpha,
*tensor_a_it,
*tensor_b_it,
beta,
*tensor_c_it,
initial_accum);
}
}
/// Computes a general matrix product among matrices (tensors of rank=2) pointed to by TensorRef
/// objects.
//
// TensorRefCollection* is a type satisfying the TensorRefCollection concept.
//
template <
typename TensorRefCollectionA,
typename TensorRefCollectionB,
typename TensorRefCollectionC,
typename ScalarType,
typename AccumulatorType
>
void BatchedGemm(
gemm::GemmCoord problem_size,
ScalarType alpha,
TensorRefCollectionA const& tensor_a,
TensorRefCollectionB const& tensor_b,
ScalarType beta,
TensorRefCollectionC &tensor_c) {
BatchedGemm(problem_size, alpha, tensor_a, tensor_b, beta, tensor_c, ScalarType(0));
}
////////////////////////////////////////////////////////////////////////////////////////////////////
} // namespace host
} // namespace reference
} // namespace cutlass