Optionally Allow Fewer Than Requested Neighbors to Be Returned

[tcheath]

In some circumstances, it would be desirable that when you ask for k nearest neighbors from the index and fewer than k are found, that however many are found are returned and the RecallError at the line below (and a similar one later in the file) would be suppressed.

voyager/cpp/src/TypedIndex.h

Lines 576 to 582 in 8e72439

	if (result.size() != (unsigned long)k) {
	throw RecallError(
	"Fewer than expected results were retrieved; only found " +
	std::to_string(result.size()) + " of " + std::to_string(k) +
	" requested neighbors. Reconstruct the index with a higher M "
	"value to increase recall.");
	}

It could be flag in either the index construction or the query args.