Module org.elasticsearch.xcore

Package org.elasticsearch.xpack.core.analytics.mapper

Class ExponentialHistogramToTDigestConverter

java.lang.Object

org.elasticsearch.xpack.core.analytics.mapper.ExponentialHistogramToTDigestConverter

public class ExponentialHistogramToTDigestConverter
extends Object

Utility class for converting ExponentialHistogram instances to t-digests represented as EncodedTDigest.CentroidIterator.

Constructor Summary

Constructors

Constructor	Description
ExponentialHistogramToTDigestConverter()

Method Summary

Modifier and Type	Method	Description
static EncodedTDigest.CentroidIterator	convert(org.elasticsearch.exponentialhistogram.ExponentialHistogram.Buckets negativeBuckets, org.elasticsearch.exponentialhistogram.ZeroBucket zeroBucket, org.elasticsearch.exponentialhistogram.ExponentialHistogram.Buckets positiveBuckets)	Converts exponential histograms to t-digests.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

ExponentialHistogramToTDigestConverter

public ExponentialHistogramToTDigestConverter()

Method Details

convert

public static EncodedTDigest.CentroidIterator convert(org.elasticsearch.exponentialhistogram.ExponentialHistogram.Buckets negativeBuckets,
 org.elasticsearch.exponentialhistogram.ZeroBucket zeroBucket,
 org.elasticsearch.exponentialhistogram.ExponentialHistogram.Buckets positiveBuckets)

Converts exponential histograms to t-digests. This algorithm computes the arithmetic bucket centers (midpoint between lower and upper bounds) and uses them as centroids for the resulting T-Digest.
Note that the conversion is partially lazy, so the BucketIterators must remain valid until the return EncodedTDigest.CentroidIterator is fully consumed. The implementation will be fully lazy if either

• The histogram to convert does not have negative buckets
• The implementation of the histogram supports a copy-free ExponentialHistogram.Buckets.reverseIterator()

Parameters:

negativeBuckets - the negative buckets of the exponential histogram

zeroBucket - the zero bucket of the exponential histogram

positiveBuckets - the positive buckets of the exponential histogram

Returns:

the resulting t-digest histogram