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Posted to commits@commons.apache.org by er...@apache.org on 2017/06/22 01:18:14 UTC
[2/3] [math] Avoid repeated computations.
Avoid repeated computations.
Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo
Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/b05bd69c
Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/b05bd69c
Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/b05bd69c
Branch: refs/heads/master
Commit: b05bd69cdd841c02a3b645568ee5478fdbfc07d1
Parents: 34adc60
Author: Gilles <er...@apache.org>
Authored: Thu Jun 22 03:14:35 2017 +0200
Committer: Gilles <er...@apache.org>
Committed: Thu Jun 22 03:14:35 2017 +0200
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.../math4/stat/interval/WilsonScoreInterval.java | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
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http://git-wip-us.apache.org/repos/asf/commons-math/blob/b05bd69c/src/main/java/org/apache/commons/math4/stat/interval/WilsonScoreInterval.java
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diff --git a/src/main/java/org/apache/commons/math4/stat/interval/WilsonScoreInterval.java b/src/main/java/org/apache/commons/math4/stat/interval/WilsonScoreInterval.java
index f36bd3b..f46ce4c 100644
--- a/src/main/java/org/apache/commons/math4/stat/interval/WilsonScoreInterval.java
+++ b/src/main/java/org/apache/commons/math4/stat/interval/WilsonScoreInterval.java
@@ -33,18 +33,18 @@ public class WilsonScoreInterval implements BinomialConfidenceInterval {
@Override
public ConfidenceInterval createInterval(int numberOfTrials, int numberOfSuccesses, double confidenceLevel) {
IntervalUtils.checkParameters(numberOfTrials, numberOfSuccesses, confidenceLevel);
- final double alpha = (1.0 - confidenceLevel) / 2;
+ final double alpha = (1 - confidenceLevel) / 2;
final NormalDistribution normalDistribution = new NormalDistribution();
final double z = normalDistribution.inverseCumulativeProbability(1 - alpha);
final double zSquared = z * z;
- final double zSquaredOverNumTrials = zSquared / numberOfTrials;
- final double mean = (double) numberOfSuccesses / (double) numberOfTrials;
+ final double oneOverNumTrials = 1d / numberOfTrials;
+ final double zSquaredOverNumTrials = zSquared * oneOverNumTrials;
+ final double mean = oneOverNumTrials * numberOfSuccesses;
- final double factor = 1.0 / (1 + zSquaredOverNumTrials);
+ final double factor = 1 / (1 + zSquaredOverNumTrials);
final double modifiedSuccessRatio = mean + zSquaredOverNumTrials / 2;
- final double difference = z *
- FastMath.sqrt(1.0 / numberOfTrials * mean * (1 - mean) +
- (zSquaredOverNumTrials / (4 * numberOfTrials)));
+ final double difference = z * FastMath.sqrt(oneOverNumTrials * mean * (1 - mean) +
+ (oneOverNumTrials * zSquaredOverNumTrials / 4));
final double lowerBound = factor * (modifiedSuccessRatio - difference);
final double upperBound = factor * (modifiedSuccessRatio + difference);