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VectorResidual.cu
/**
* Copyright (c) 2015-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the CC-by-NC license found in the
* LICENSE file in the root directory of this source tree.
*/
// Copyright 2004-present Facebook. All Rights Reserved.
#include "VectorResidual.cuh"
#include "../../FaissAssert.h"
#include "../utils/ConversionOperators.cuh"
#include "../utils/DeviceUtils.h"
#include "../utils/Tensor.cuh"
#include "../utils/StaticUtils.h"
#include <math_constants.h> // in CUDA SDK, for CUDART_NAN_F
namespace faiss { namespace gpu {
template <typename CentroidT, bool LargeDim>
__global__ void calcResidual(Tensor<float, 2, true> vecs,
Tensor<CentroidT, 2, true> centroids,
Tensor<int, 1, true> vecToCentroid,
Tensor<float, 2, true> residuals) {
auto vec = vecs[blockIdx.x];
auto residual = residuals[blockIdx.x];
int centroidId = vecToCentroid[blockIdx.x];
// Vector could be invalid (containing NaNs), so -1 was the
// classified centroid
if (centroidId == -1) {
if (LargeDim) {
for (int i = threadIdx.x; i < vecs.getSize(1); i += blockDim.x) {
residual[i] = CUDART_NAN_F;
}
} else {
residual[threadIdx.x] = CUDART_NAN_F;
}
return;
}
auto centroid = centroids[centroidId];
if (LargeDim) {
for (int i = threadIdx.x; i < vecs.getSize(1); i += blockDim.x) {
residual[i] = vec[i] - ConvertTo<float>::to(centroid[i]);
}
} else {
residual[threadIdx.x] = vec[threadIdx.x] -
ConvertTo<float>::to(centroid[threadIdx.x]);
}
}
template <typename CentroidT>
void calcResidual(Tensor<float, 2, true>& vecs,
Tensor<CentroidT, 2, true>& centroids,
Tensor<int, 1, true>& vecToCentroid,
Tensor<float, 2, true>& residuals,
cudaStream_t stream) {
FAISS_ASSERT(vecs.getSize(1) == centroids.getSize(1));
FAISS_ASSERT(vecs.getSize(1) == residuals.getSize(1));
FAISS_ASSERT(vecs.getSize(0) == vecToCentroid.getSize(0));
FAISS_ASSERT(vecs.getSize(0) == residuals.getSize(0));
dim3 grid(vecs.getSize(0));
int maxThreads = getMaxThreadsCurrentDevice();
bool largeDim = vecs.getSize(1) > maxThreads;
dim3 block(std::min(vecs.getSize(1), maxThreads));
if (largeDim) {
calcResidual<CentroidT, true><<<grid, block, 0, stream>>>(
vecs, centroids, vecToCentroid, residuals);
} else {
calcResidual<CentroidT, false><<<grid, block, 0, stream>>>(
vecs, centroids, vecToCentroid, residuals);
}
}
void runCalcResidual(Tensor<float, 2, true>& vecs,
Tensor<float, 2, true>& centroids,
Tensor<int, 1, true>& vecToCentroid,
Tensor<float, 2, true>& residuals,
cudaStream_t stream) {
calcResidual<float>(vecs, centroids, vecToCentroid, residuals, stream);
}
#ifdef FAISS_USE_FLOAT16
void runCalcResidual(Tensor<float, 2, true>& vecs,
Tensor<half, 2, true>& centroids,
Tensor<int, 1, true>& vecToCentroid,
Tensor<float, 2, true>& residuals,
cudaStream_t stream) {
calcResidual<half>(vecs, centroids, vecToCentroid, residuals, stream);
}
#endif
} } // namespace