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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "nns.h"
#include <iostream>
#include "/git/hnswlib/hnswlib/hnswlib.h"
class HnswWrapNns : public NNS<float>
{
private:
using Implementation = hnswlib::HierarchicalNSW<float>;
hnswlib::L2Space _l2space;
Implementation _hnsw;
public:
HnswWrapNns(uint32_t numDims, const DocVectorAccess<float> &dva)
: NNS(numDims, dva),
_l2space(numDims),
_hnsw(&_l2space, 2500000, 16, 200)
{
}
~HnswWrapNns() {}
void addDoc(uint32_t docid) override {
Vector vector = _dva.get(docid);
_hnsw.addPoint(vector.cbegin(), docid);
}
void removeDoc(uint32_t docid) override {
_hnsw.markDelete(docid);
}
std::vector<NnsHit> topK(uint32_t k, Vector vector, uint32_t search_k) override {
std::vector<NnsHit> reversed;
_hnsw.setEf(search_k);
auto priQ = _hnsw.searchKnn(vector.cbegin(), k);
while (! priQ.empty()) {
auto pair = priQ.top();
reversed.emplace_back(pair.second, SqDist(pair.first));
priQ.pop();
}
std::vector<NnsHit> result;
while (result.size() < k && !reversed.empty()) {
result.push_back(reversed.back());
reversed.pop_back();
}
return result;
}
std::vector<NnsHit> topKfilter(uint32_t k, Vector vector, uint32_t search_k, const BitVector &skipDocIds) override {
std::vector<NnsHit> reversed;
uint32_t adjusted_k = k+4;
uint32_t adjusted_sk = search_k+4;
for (int retry = 0; (retry < 5) && (reversed.size() < k); ++retry) {
reversed.clear();
_hnsw.setEf(adjusted_sk);
auto priQ = _hnsw.searchKnn(vector.cbegin(), adjusted_k);
while (! priQ.empty()) {
auto pair = priQ.top();
if (! skipDocIds.isSet(pair.second)) {
reversed.emplace_back(pair.second, SqDist(pair.first));
}
priQ.pop();
}
double got = 1 + reversed.size();
double factor = 1.25 * k / got;
adjusted_k *= factor;
adjusted_sk *= factor;
}
std::vector<NnsHit> result;
while (result.size() < k && !reversed.empty()) {
result.push_back(reversed.back());
reversed.pop_back();
}
return result;
}
};
std::unique_ptr<NNS<float>>
make_hnsw_wrap(uint32_t numDims, const DocVectorAccess<float> &dva)
{
NNS<float> *p = new HnswWrapNns(numDims, dva);
return std::unique_ptr<NNS<float>>(p);
}
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