Method cardinality

solr/core/src/java/org/apache/solr/util/hll/HLL.java:545–558

Computes the cardinality of the HLL. @return the cardinality of HLL. This will never be negative.

()

   * @return the cardinality of HLL. This will never be negative.
   */
  public long cardinality() {
    switch (type) {
      case EMPTY:
        return 0 /*by definition*/;
      case EXPLICIT:
        return explicitStorage.size();
      case SPARSE:
        return (long) Math.ceil(sparseProbabilisticAlgorithmCardinality());
      case FULL:
        return (long) Math.ceil(fullProbabilisticAlgorithmCardinality());
      default:
        throw new RuntimeException("Unsupported HLL type " + type);
    }
  }

  // ------------------------------------------------------------------------
  // Cardinality helpers