faiss/gpu/impl/IVFBase.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/MetricType.h>
#include <faiss/gpu/GpuIndicesOptions.h>
#include <faiss/gpu/utils/DeviceVector.cuh>
#include <faiss/gpu/utils/DeviceTensor.cuh>
#include <faiss/gpu/utils/MemorySpace.h>
#include <memory>
#include <thrust/device_vector.h>
#include <vector>
namespace faiss { namespace gpu {
class GpuResources;
struct FlatIndex;
/// Base inverted list functionality for IVFFlat and IVFPQ
class IVFBase {
public:
IVFBase(GpuResources* resources,
faiss::MetricType metric,
float metricArg,
/// We do not own this reference
FlatIndex* quantizer,
int bytesPerVector,
IndicesOptions indicesOptions,
MemorySpace space);
virtual ~IVFBase();
/// Reserve GPU memory in our inverted lists for this number of vectors
void reserveMemory(size_t numVecs);
/// Clear out all inverted lists, but retain the coarse quantizer
/// and the product quantizer info
void reset();
/// Return the number of dimensions we are indexing
int getDim() const;
/// After adding vectors, one can call this to reclaim device memory
/// to exactly the amount needed. Returns space reclaimed in bytes
size_t reclaimMemory();
/// Returns the number of inverted lists
size_t getNumLists() const;
/// For debugging purposes, return the list length of a particular
/// list
int getListLength(int listId) const;
/// Return the list indices of a particular list back to the CPU
std::vector<long> getListIndices(int listId) const;
/// Return the encoded vectors of a particular list back to the CPU
std::vector<unsigned char> getListVectors(int listId) const;
protected:
/// Reclaim memory consumed on the device for our inverted lists
/// `exact` means we trim exactly to the memory needed
size_t reclaimMemory_(bool exact);
/// Update all device-side list pointer and size information
void updateDeviceListInfo_(cudaStream_t stream);
/// For a set of list IDs, update device-side list pointer and size
/// information
void updateDeviceListInfo_(const std::vector<int>& listIds,
cudaStream_t stream);
/// Shared function to copy indices from CPU to GPU
void addIndicesFromCpu_(int listId,
const long* indices,
size_t numVecs);
protected:
/// Collection of GPU resources that we use
GpuResources* resources_;
/// Metric type of the index
faiss::MetricType metric_;
/// Metric arg
float metricArg_;
/// Quantizer object
FlatIndex* quantizer_;
/// Expected dimensionality of the vectors
const int dim_;
/// Number of inverted lists we maintain
const int numLists_;
/// Number of bytes per vector in the list
const int bytesPerVector_;
/// How are user indices stored on the GPU?
const IndicesOptions indicesOptions_;
/// What memory space our inverted list storage is in
const MemorySpace space_;
/// Device representation of all inverted list data
/// id -> data
thrust::device_vector<void*> deviceListDataPointers_;
/// Device representation of all inverted list index pointers
/// id -> data
thrust::device_vector<void*> deviceListIndexPointers_;
/// Device representation of all inverted list lengths
/// id -> length
thrust::device_vector<int> deviceListLengths_;
/// Maximum list length seen
int maxListLength_;
/// Device memory for each separate list, as managed by the host.
/// Device memory as stored in DeviceVector is stored as unique_ptr
/// since deviceListSummary_ pointers must remain valid despite
/// resizing of deviceLists_
std::vector<std::unique_ptr<DeviceVector<unsigned char>>> deviceListData_;
std::vector<std::unique_ptr<DeviceVector<unsigned char>>> deviceListIndices_;
/// If we are storing indices on the CPU (indicesOptions_ is
/// INDICES_CPU), then this maintains a CPU-side map of what
/// (inverted list id, offset) maps to which user index
std::vector<std::vector<long>> listOffsetToUserIndex_;
};
} } // namespace