Module org.elasticsearch.exponentialhistogram

Package org.elasticsearch.exponentialhistogram

Class ExponentialHistogramUtils

java.lang.Object

org.elasticsearch.exponentialhistogram.ExponentialHistogramUtils

public class ExponentialHistogramUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static final record	ExponentialHistogramUtils.HistogramPair

Constructor Summary

Constructors

Constructor	Description
ExponentialHistogramUtils()

Method Summary

Modifier and Type	Method	Description
static OptionalDouble	estimateMax(ZeroBucket zeroBucket, ExponentialHistogram.Buckets negativeBuckets, ExponentialHistogram.Buckets positiveBuckets)	Estimates the maximum value of the histogram based on the populated buckets.
static OptionalDouble	estimateMin(ZeroBucket zeroBucket, ExponentialHistogram.Buckets negativeBuckets, ExponentialHistogram.Buckets positiveBuckets)	Estimates the minimum value of the histogram based on the populated buckets.
static double	estimateSum(BucketIterator negativeBuckets, BucketIterator positiveBuckets)	Estimates the sum of all values of a histogram just based on the populated buckets.
static ExponentialHistogramUtils.HistogramPair	removeMergeNoise(ExponentialHistogram first, ExponentialHistogram second)	Makes sure that if both histograms were generated by merging the same set of histograms, they are equal independent of the order in which the merge occurred.

Methods inherited from class java.lang.Object

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

Constructor Details

ExponentialHistogramUtils

public ExponentialHistogramUtils()

Method Details

estimateSum

public static double estimateSum(BucketIterator negativeBuckets,
 BucketIterator positiveBuckets)

Estimates the sum of all values of a histogram just based on the populated buckets. Will never return NaN, but might return +/-Infinity if the histogram is too big.

Parameters:

negativeBuckets - the negative buckets of the histogram

positiveBuckets - the positive buckets of the histogram

Returns:

the estimated sum of all values in the histogram, guaranteed to be zero if there are no buckets.

estimateMin

public static OptionalDouble estimateMin(ZeroBucket zeroBucket,
 ExponentialHistogram.Buckets negativeBuckets,
 ExponentialHistogram.Buckets positiveBuckets)

Estimates the minimum value of the histogram based on the populated buckets. The returned value is guaranteed to be less than or equal to the exact minimum value of the histogram values. If the histogram is empty, an empty Optional is returned.

Note that this method can return +-Infinity if the histogram bucket boundaries are not representable in a double.

Parameters:

zeroBucket - the zero bucket of the histogram

negativeBuckets - the negative buckets of the histogram

positiveBuckets - the positive buckets of the histogram

Returns:

the estimated minimum

estimateMax

public static OptionalDouble estimateMax(ZeroBucket zeroBucket,
 ExponentialHistogram.Buckets negativeBuckets,
 ExponentialHistogram.Buckets positiveBuckets)

Estimates the maximum value of the histogram based on the populated buckets. The returned value is guaranteed to be greater than or equal to the exact maximum value of the histogram values. If the histogram is empty, an empty Optional is returned.

Note that this method can return +-Infinity if the histogram bucket boundaries are not representable in a double.

Parameters:

zeroBucket - the zero bucket of the histogram

negativeBuckets - the negative buckets of the histogram

positiveBuckets - the positive buckets of the histogram

Returns:

the estimated minimum

removeMergeNoise

public static ExponentialHistogramUtils.HistogramPair removeMergeNoise(ExponentialHistogram first,
 ExponentialHistogram second)

Makes sure that if both histograms were generated by merging the same set of histograms, they are equal independent of the order in which the merge occurred. This utility is intended for usage in tests.

Parameters:

first - the first histogram

second - the second histogram

Returns:

the adjusted histograms