org.eclipse.jetty.util.statistic
Class SampleStatistic
java.lang.Object
org.eclipse.jetty.util.statistic.SampleStatistic
public class SampleStatistic
- extends Object
SampledStatistics
Provides max, total, mean, count, variance, and standard
deviation of continuous sequence of samples.
Calculates estimates of mean, variance, and standard deviation
characteristics of a sample using a non synchronized
approximation of the on-line algorithm presented
in Donald Knuth's Art of Computer Programming, Volume 2,
Seminumerical Algorithms, 3rd edition, page 232,
Boston: Addison-Wesley. that cites a 1962 paper by B.P. Welford
that can be found by following the link http://www.jstor.org/pss/1266577
This algorithm is also described in Wikipedia at
http://en.wikipedia.org/w/index.php?title=Algorithms_for_calculating_variance§ion=4#On-line_algorithm
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
_max
protected final AtomicLong _max
_total
protected final AtomicLong _total
_count
protected final AtomicLong _count
_totalVariance100
protected final AtomicLong _totalVariance100
SampleStatistic
public SampleStatistic()
reset
public void reset()
set
public void set(long sample)
getMax
public long getMax()
- Returns:
- the max value
getTotal
public long getTotal()
getCount
public long getCount()
getMean
public double getMean()
getVariance
public double getVariance()
getStdDev
public double getStdDev()
Copyright © 1995-2010 Mort Bay Consulting. All Rights Reserved.