faiss/gpu/impl/IVFUtils.cuh

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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.
*/
#pragma once
#include <faiss/gpu/GpuIndicesOptions.h>
#include <faiss/gpu/utils/Tensor.cuh>
#include <thrust/device_vector.h>
// A collection of utility functions for IVFPQ and IVFFlat, for
// post-processing and k-selecting the results
namespace faiss { namespace gpu {
/// Function for multi-pass scanning that collects the length of
/// intermediate results for all (query, probe) pair
void runCalcListOffsets(Tensor<int, 2, true>& topQueryToCentroid,
thrust::device_vector<int>& listLengths,
Tensor<int, 2, true>& prefixSumOffsets,
Tensor<char, 1, true>& thrustMem,
cudaStream_t stream);
/// Performs a first pass of k-selection on the results
void runPass1SelectLists(Tensor<int, 2, true>& prefixSumOffsets,
Tensor<float, 1, true>& distance,
int nprobe,
int k,
bool chooseLargest,
Tensor<float, 3, true>& heapDistances,
Tensor<int, 3, true>& heapIndices,
cudaStream_t stream);
/// Performs a final pass of k-selection on the results, producing the
/// final indices
void runPass2SelectLists(Tensor<float, 2, true>& heapDistances,
Tensor<int, 2, true>& heapIndices,
thrust::device_vector<void*>& listIndices,
IndicesOptions indicesOptions,
Tensor<int, 2, true>& prefixSumOffsets,
Tensor<int, 2, true>& topQueryToCentroid,
int k,
bool chooseLargest,
Tensor<float, 2, true>& outDistances,
Tensor<long, 2, true>& outIndices,
cudaStream_t stream);
} } // namespace