fixed bug with cardinality estimation when sketch is not completely full (df293b89) · Commits · github_fork / Chromap

src/chromap.h

+4 −7

Original line number	Diff line number	Diff line
		@@ -49,9 +49,7 @@ public:
		*/
		K_MinHash(size_t k, size_t range) : k_(k), range_(range) {}

		// K_MinHash(): k_(250), range_(4000003) {}

		void add(size_t num) {
		inline void add(size_t num) {
		/* If num is not present in queue, we will add it */
		if (unique_slots_.find(num) == unique_slots_.end()) {
		unique_slots_.insert(num);
		@@ -64,11 +62,10 @@ public:
		}
		}

		size_t compute_cardinality() {
		inline size_t compute_cardinality() {
		/* Use k-MinHash estimator to return estimated cardinality */
		size_t k_for_calc = k_;
		if (pq_.size() < k_) {k_for_calc = pq_.size();}
		size_t cardinality = (k_for_calc * range_)/pq_.top() - 1;
		if (pq_.size() < k_) {return 0;}
		size_t cardinality = (k_ * range_)/pq_.top() - 1;
		return cardinality;
		}