java.lang.Object
org.elasticsearch.tdigest.TDigest
org.elasticsearch.tdigest.AbstractTDigest
org.elasticsearch.tdigest.SortingDigest
- All Implemented Interfaces:
Closeable,AutoCloseable,org.apache.lucene.util.Accountable,Releasable
Simple implementation of the TDigest interface that stores internally and sorts all samples to calculate quantiles and CDFs.
It provides perfect quantile and cdf calculations and matches or exceeds the performance of MergingDigest at least for millions of
samples, at the expense of allocating much more memory.
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Field Summary
Fields inherited from interface org.apache.lucene.util.Accountable
NULL_ACCOUNTABLE -
Method Summary
Modifier and TypeMethodDescriptionvoidadd(double x, long w) Adds a sample to a histogram.intbyteSize()Returns an upper bound on the number bytes that will be required to represent this histogram.doublecdf(double x) Returns the fraction of all points added which are ≤ x.intACollectionthat lets you go through the centroids in ascending order by mean.voidclose()voidcompress()Re-examines a t-digest to determine whether some centroids are redundant.doubleReturns the current compression factor.doublequantile(double q) Returns an estimate of a cutoff such that a specified fraction of the data added to this TDigest would be less than or equal to the cutoff.longvoidreserve(long size) Prepare internal structure for loading the requested number of samples.longsize()Returns the number of points that have been added to this TDigest.Methods inherited from class org.elasticsearch.tdigest.AbstractTDigest
addMethods inherited from class org.elasticsearch.tdigest.TDigest
add, createAvlTreeDigest, createHybridDigest, createMergingDigest, createSortingDigest, getMax, getMin, setScaleFunctionMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods inherited from interface org.apache.lucene.util.Accountable
getChildResources
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Method Details
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ramBytesUsed
public long ramBytesUsed() -
add
public void add(double x, long w) Description copied from class:TDigestAdds a sample to a histogram. -
compress
public void compress()Description copied from class:TDigestRe-examines a t-digest to determine whether some centroids are redundant. If your data are perversely ordered, this may be a good idea. Even if not, this may save 20% or so in space. The cost is roughly the same as adding as many data points as there are centroids. This is typically < 10 * compression, but could be as high as 100 * compression. This is a destructive operation that is not thread-safe. -
size
public long size()Description copied from class:TDigestReturns the number of points that have been added to this TDigest. -
cdf
public double cdf(double x) Description copied from class:TDigestReturns the fraction of all points added which are ≤ x. Points that are exactly equal get half credit (i.e. we use the mid-point rule) -
quantile
public double quantile(double q) Description copied from class:TDigestReturns an estimate of a cutoff such that a specified fraction of the data added to this TDigest would be less than or equal to the cutoff. -
centroids
Description copied from class:TDigestACollectionthat lets you go through the centroids in ascending order by mean. Centroids returned will not be re-used, but may or may not share storage with this TDigest. -
compression
public double compression()Description copied from class:TDigestReturns the current compression factor.- Specified by:
compressionin classTDigest- Returns:
- The compression factor originally used to set up the TDigest.
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centroidCount
public int centroidCount()- Specified by:
centroidCountin classTDigest
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reserve
public void reserve(long size) Description copied from class:TDigestPrepare internal structure for loading the requested number of samples. -
byteSize
public int byteSize()Returns an upper bound on the number bytes that will be required to represent this histogram. -
close
public void close()
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