About interface

[orrorcol]

I'm integrating hnswlib into my own code, I have the following suggestions:

1. I think that the data passed to addPoint should be const void * .

hnswlib/hnswlib/hnswalg.h

Line 773 in 44f20f0

void addPoint(void *data_point, labeltype label) {

2. I think that searchKnn shuld first check if the "container" is empty, in wich case a search may result in a core dump.
   

   hnswlib/hnswlib/hnswalg.h

   Line 486 in 44f20f0

   std::priority_queue<std::pair<dist_t, tableint>> searchKnnInternal(void *query_data, int k) {

[orrorcol]

Another suggestion: the result points are aranged in a max heap, while what people interested in is the nearest points. I would suggest using another comparator that would return a min heap.

hnswlib/hnswlib/hnswalg.h

Lines 928 to 937 in 44f20f0

	std::priority_queue<std::pair<dist_t, labeltype >> results;
	while (top_candidates.size() > k) {
	top_candidates.pop();
	}
	while (top_candidates.size() > 0) {
	std::pair<dist_t, tableint> rez = top_candidates.top();
	results.push(std::pair<dist_t, labeltype>(rez.first, getExternalLabel(rez.second)));
	top_candidates.pop();
	}
	return results;

[yurymalkov]

@uestc-lfs Thanks for the suggestions! Seems reasonable.

[orrorcol]

Would you like some pull requests for these suggestions?

[yurymalkov]

@uestc-lfs
Yeah, sure. That would be great!
I've already started to implement them, but was distracted by other things...