faiss/gpu/GpuDistance.cu

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/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
#include <faiss/gpu/GpuDistance.h>
#include <faiss/impl/FaissAssert.h>
#include <faiss/gpu/GpuResources.h>
#include <faiss/gpu/impl/Distance.cuh>
#include <faiss/gpu/utils/ConversionOperators.cuh>
#include <faiss/gpu/utils/CopyUtils.cuh>
#include <faiss/gpu/utils/DeviceUtils.h>
#include <faiss/gpu/utils/DeviceTensor.cuh>
namespace faiss { namespace gpu {
void bruteForceKnn(GpuResources* resources,
faiss::MetricType metric,
// A region of memory size numVectors x dims, with dims
// innermost
const float* vectors,
bool vectorsRowMajor,
int numVectors,
// A region of memory size numQueries x dims, with dims
// innermost
const float* queries,
bool queriesRowMajor,
int numQueries,
int dims,
int k,
// A region of memory size numQueries x k, with k
// innermost
float* outDistances,
// A region of memory size numQueries x k, with k
// innermost
faiss::Index::idx_t* outIndices) {
auto device = getCurrentDevice();
auto stream = resources->getDefaultStreamCurrentDevice();
auto& mem = resources->getMemoryManagerCurrentDevice();
auto tVectors = toDevice<float, 2>(resources,
device,
const_cast<float*>(vectors),
stream,
{vectorsRowMajor ? numVectors : dims,
vectorsRowMajor ? dims : numVectors});
auto tQueries = toDevice<float, 2>(resources,
device,
const_cast<float*>(queries),
stream,
{queriesRowMajor ? numQueries : dims,
queriesRowMajor ? dims : numQueries});
auto tOutDistances = toDevice<float, 2>(resources,
device,
outDistances,
stream,
{numQueries, k});
// FlatIndex only supports an interface returning int indices, allocate
// temporary memory for it
DeviceTensor<int, 2, true> tOutIntIndices(mem, {numQueries, k}, stream);
// Do the work
if (metric == faiss::MetricType::METRIC_L2) {
runL2Distance(resources,
tVectors,
vectorsRowMajor,
nullptr, // compute norms in temp memory
tQueries,
queriesRowMajor,
k,
tOutDistances,
tOutIntIndices);
} else if (metric == faiss::MetricType::METRIC_INNER_PRODUCT) {
runIPDistance(resources,
tVectors,
vectorsRowMajor,
tQueries,
queriesRowMajor,
k,
tOutDistances,
tOutIntIndices);
} else {
FAISS_THROW_MSG("metric should be METRIC_L2 or METRIC_INNER_PRODUCT");
}
// Convert and copy int indices out
auto tOutIndices = toDevice<faiss::Index::idx_t, 2>(resources,
device,
outIndices,
stream,
{numQueries, k});
// Convert int to idx_t
convertTensor<int, faiss::Index::idx_t, 2>(stream,
tOutIntIndices,
tOutIndices);
// Copy back if necessary
fromDevice<float, 2>(tOutDistances, outDistances, stream);
fromDevice<faiss::Index::idx_t, 2>(tOutIndices, outIndices, stream);
}
} } // namespace