Repository: commons-math Updated Branches: refs/heads/feature-MATH-1158 ae2c81ad1 -> b57780534
MATH-1343 Unnecessary recomputation. Project: http://git-wip-us.apache.org/repos/asf/commons-math/repo Commit: http://git-wip-us.apache.org/repos/asf/commons-math/commit/b5778053 Tree: http://git-wip-us.apache.org/repos/asf/commons-math/tree/b5778053 Diff: http://git-wip-us.apache.org/repos/asf/commons-math/diff/b5778053 Branch: refs/heads/feature-MATH-1158 Commit: b577805347d56f1927615fad311868a3537a9cb6 Parents: ae2c81a Author: Gilles <er...@apache.org> Authored: Sat Mar 26 02:32:10 2016 +0100 Committer: Gilles <er...@apache.org> Committed: Sat Mar 26 02:32:10 2016 +0100 ---------------------------------------------------------------------- .../math4/distribution/BetaDistribution.java | 16 +++------------- 1 file changed, 3 insertions(+), 13 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/commons-math/blob/b5778053/src/main/java/org/apache/commons/math4/distribution/BetaDistribution.java ---------------------------------------------------------------------- diff --git a/src/main/java/org/apache/commons/math4/distribution/BetaDistribution.java b/src/main/java/org/apache/commons/math4/distribution/BetaDistribution.java index 987e8eb..abccb93 100644 --- a/src/main/java/org/apache/commons/math4/distribution/BetaDistribution.java +++ b/src/main/java/org/apache/commons/math4/distribution/BetaDistribution.java @@ -42,10 +42,8 @@ public class BetaDistribution extends AbstractRealDistribution { private final double alpha; /** Second shape parameter. */ private final double beta; - /** Normalizing factor used in density computations. - * updated whenever alpha or beta are changed. - */ - private double z; + /** Normalizing factor used in density computations.*/ + private final double z; /** Inverse cumulative probability accuracy. */ private final double solverAbsoluteAccuracy; @@ -75,7 +73,7 @@ public class BetaDistribution extends AbstractRealDistribution { double inverseCumAccuracy) { this.alpha = alpha; this.beta = beta; - z = Double.NaN; + z = Gamma.logGamma(alpha) + Gamma.logGamma(beta) - Gamma.logGamma(alpha + beta); solverAbsoluteAccuracy = inverseCumAccuracy; } @@ -97,13 +95,6 @@ public class BetaDistribution extends AbstractRealDistribution { return beta; } - /** Recompute the normalization factor. */ - private void recomputeZ() { - if (Double.isNaN(z)) { - z = Gamma.logGamma(alpha) + Gamma.logGamma(beta) - Gamma.logGamma(alpha + beta); - } - } - /** {@inheritDoc} */ @Override public double density(double x) { @@ -114,7 +105,6 @@ public class BetaDistribution extends AbstractRealDistribution { /** {@inheritDoc} **/ @Override public double logDensity(double x) { - recomputeZ(); if (x < 0 || x > 1) { return Double.NEGATIVE_INFINITY; } else if (x == 0) {
