private void runMergeTrials()

in src/main/java/org/apache/datasketches/characterization/hll/HllMergeAccuracyProfile.java [48:81]

31 lines of code
4 McCabe index (conditional complexity)


  private void runMergeTrials() {
    long key = random.nextLong();

    final int lgK = Integer.parseInt(job.getProperties().mustGet("lgK"));
    final int numTrials = Integer.parseInt(job.getProperties().mustGet("numTrials"));
    final int numSketches = Integer.parseInt(job.getProperties().mustGet("numSketches"));
    final int distinctKeysPerSketch = Integer.parseInt(job.getProperties().mustGet("distinctKeysPerSketch"));
    final double trueCount = numSketches * distinctKeysPerSketch;
    double sumEstimates = 0;
    double sumOfSquaredDeviationsFromTrueCount = 0;

    for (int t = 0; t < numTrials; t++) {
      final Union union = new Union(lgK);

      for (int s = 0; s < numSketches; s++) {
        final HllSketch sketch = new HllSketch(lgK, TgtHllType.HLL_8);
        for (int k = 0; k < distinctKeysPerSketch; k++) {
          sketch.update(key++);
        }
        union.update(sketch);
      }
      final double estimatedCount = union.getResult().getEstimate();
      sumEstimates += estimatedCount;
      sumOfSquaredDeviationsFromTrueCount += (estimatedCount - trueCount) * (estimatedCount - trueCount);
    }
    final double meanEstimate = sumEstimates / numTrials;
    final double meanRelativeError = meanEstimate / trueCount - 1;
    final double relativeStandardError
      = Math.sqrt(sumOfSquaredDeviationsFromTrueCount / numTrials) / trueCount;
    job.println("True count: " + trueCount);
    job.println("Mean estimate: " + meanEstimate);
    job.println("Mean Relative Error: " + meanRelativeError);
    job.println("Relative Standard Error: " + relativeStandardError);
  }