147 lines
3.2 KiB
C++
147 lines
3.2 KiB
C++
/**
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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// -*- c++ -*-
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#include "AuxIndexStructures.h"
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#include "FaissAssert.h"
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#include "utils.h"
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#include <cstring>
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namespace faiss {
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Index::~Index ()
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{
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}
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void Index::train(idx_t /*n*/, const float* /*x*/) {
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// does nothing by default
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}
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void Index::range_search (idx_t , const float *, float,
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RangeSearchResult *) const
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{
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FAISS_THROW_MSG ("range search not implemented");
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}
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void Index::assign (idx_t n, const float * x, idx_t * labels, idx_t k)
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{
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float * distances = new float[n * k];
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ScopeDeleter<float> del(distances);
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search (n, x, k, distances, labels);
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}
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void Index::add_with_ids(
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idx_t /*n*/,
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const float* /*x*/,
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const idx_t* /*xids*/) {
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FAISS_THROW_MSG ("add_with_ids not implemented for this type of index");
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}
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size_t Index::remove_ids(const IDSelector& /*sel*/) {
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FAISS_THROW_MSG ("remove_ids not implemented for this type of index");
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return -1;
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}
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void Index::reconstruct (idx_t, float * ) const {
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FAISS_THROW_MSG ("reconstruct not implemented for this type of index");
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}
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void Index::reconstruct_n (idx_t i0, idx_t ni, float *recons) const {
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for (idx_t i = 0; i < ni; i++) {
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reconstruct (i0 + i, recons + i * d);
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}
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}
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void Index::search_and_reconstruct (idx_t n, const float *x, idx_t k,
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float *distances, idx_t *labels,
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float *recons) const {
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search (n, x, k, distances, labels);
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for (idx_t i = 0; i < n; ++i) {
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for (idx_t j = 0; j < k; ++j) {
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idx_t ij = i * k + j;
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idx_t key = labels[ij];
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float* reconstructed = recons + ij * d;
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if (key < 0) {
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// Fill with NaNs
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memset(reconstructed, -1, sizeof(*reconstructed) * d);
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} else {
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reconstruct (key, reconstructed);
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}
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}
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}
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}
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void Index::compute_residual (const float * x,
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float * residual, idx_t key) const {
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reconstruct (key, residual);
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for (size_t i = 0; i < d; i++)
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residual[i] = x[i] - residual[i];
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}
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void Index::display () const {
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printf ("Index: %s -> %ld elements\n", typeid (*this).name(), ntotal);
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}
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namespace {
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// storage that explicitly reconstructs vectors before computing distances
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struct GenericDistanceComputer : DistanceComputer {
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size_t d;
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const Index& storage;
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std::vector<float> buf;
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const float *q;
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explicit GenericDistanceComputer(const Index& storage)
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: storage(storage) {
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d = storage.d;
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buf.resize(d * 2);
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}
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float operator () (idx_t i) override {
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storage.reconstruct(i, buf.data());
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return fvec_L2sqr(q, buf.data(), d);
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}
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float symmetric_dis(idx_t i, idx_t j) override {
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storage.reconstruct(i, buf.data());
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storage.reconstruct(j, buf.data() + d);
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return fvec_L2sqr(buf.data() + d, buf.data(), d);
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}
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void set_query(const float *x) override {
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q = x;
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}
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};
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} // namespace
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DistanceComputer * Index::get_distance_computer() const {
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if (metric_type == METRIC_L2) {
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return new GenericDistanceComputer(*this);
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} else {
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FAISS_THROW_MSG ("get_distance_computer() not implemented");
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}
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}
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}
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