76 lines
1.7 KiB
C++
76 lines
1.7 KiB
C++
/**
|
|
* 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.
|
|
*/
|
|
|
|
// -*- c++ -*-
|
|
|
|
#ifndef FAISS_INDEX_IVFSH_H
|
|
#define FAISS_INDEX_IVFSH_H
|
|
|
|
|
|
#include <vector>
|
|
|
|
#include <faiss/IndexIVF.h>
|
|
|
|
|
|
namespace faiss {
|
|
|
|
struct VectorTransform;
|
|
|
|
/** Inverted list that stores binary codes of size nbit. Before the
|
|
* binary conversion, the dimension of the vectors is transformed from
|
|
* dim d into dim nbit by vt (a random rotation by default).
|
|
*
|
|
* Each coordinate is subtracted from a value determined by
|
|
* threshold_type, and split into intervals of size period. Half of
|
|
* the interval is a 0 bit, the other half a 1.
|
|
*/
|
|
struct IndexIVFSpectralHash: IndexIVF {
|
|
|
|
VectorTransform *vt; // transformation from d to nbit dim
|
|
bool own_fields;
|
|
|
|
int nbit;
|
|
float period;
|
|
|
|
enum ThresholdType {
|
|
Thresh_global,
|
|
Thresh_centroid,
|
|
Thresh_centroid_half,
|
|
Thresh_median
|
|
};
|
|
ThresholdType threshold_type;
|
|
|
|
// size nlist * nbit or 0 if Thresh_global
|
|
std::vector<float> trained;
|
|
|
|
IndexIVFSpectralHash (Index * quantizer, size_t d, size_t nlist,
|
|
int nbit, float period);
|
|
|
|
IndexIVFSpectralHash ();
|
|
|
|
void train_residual(idx_t n, const float* x) override;
|
|
|
|
void encode_vectors(idx_t n, const float* x,
|
|
const idx_t *list_nos,
|
|
uint8_t * codes,
|
|
bool include_listnos = false) const override;
|
|
|
|
InvertedListScanner *get_InvertedListScanner (bool store_pairs)
|
|
const override;
|
|
|
|
~IndexIVFSpectralHash () override;
|
|
|
|
};
|
|
|
|
|
|
|
|
|
|
}; // namespace faiss
|
|
|
|
|
|
#endif
|