/**
 * 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

/** In this file are the implementations of extra metrics beyond L2
 *  and inner product */

#include <stdint.h>

#include <faiss/Index.h>

#include <faiss/utils/Heap.h>

namespace faiss {

struct FlatCodesDistanceComputer;
struct IDSelector;

void pairwise_extra_distances(
        int64_t d,
        int64_t nq,
        const float* xq,
        int64_t nb,
        const float* xb,
        MetricType mt,
        float metric_arg,
        float* dis,
        int64_t ldq = -1,
        int64_t ldb = -1,
        int64_t ldd = -1);

template <class C>
void knn_extra_metrics(
        const float* x,
        const float* y,
        size_t d,
        size_t nx,
        size_t ny,
        MetricType mt,
        float metric_arg,
        HeapArray<C>* res,
        const IDSelector* sel = nullptr);

/** get a DistanceComputer that refers to this type of distance and
 *  indexes a flat array of size nb */
FlatCodesDistanceComputer* get_extra_distance_computer(
        size_t d,
        MetricType mt,
        float metric_arg,
        size_t nb,
        const float* xb);

} // namespace faiss

#include <faiss/utils/extra_distances-inl.h>
