[commons-statistics] 24/35: LogNormalDistribution: remove impossible condition

[ah...@apache.org]

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aherbert pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/commons-statistics.git

commit dc30ade59f7f65ad210a30295ace6887cddbfa07
Author: aherbert <ah...@apache.org>
AuthorDate: Tue Jun 23 16:21:31 2020 +0100

    LogNormalDistribution: remove impossible condition
    
    If x0 is not larger than x1, and x0 is larger than zero, then x1 cannot
    be zero or below. Thus this condition:
    
    if (x0 <= 0 || x1 <= 0)
    
    can only be true in the second part if x0 is NaN. NaN checking is not
    supported so we can drop the second condition.
---
 .../apache/commons/statistics/distribution/LogNormalDistribution.java  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/LogNormalDistribution.java b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/LogNormalDistribution.java
index 0fbe7bd..cb05e5e 100644
--- a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/LogNormalDistribution.java
+++ b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/LogNormalDistribution.java
@@ -162,9 +162,10 @@ public class LogNormalDistribution extends AbstractContinuousDistribution {
             throw new DistributionException(DistributionException.TOO_LARGE,
                                             x0, x1);
         }
-        if (x0 <= 0 || x1 <= 0) {
+        if (x0 <= 0) {
             return super.probability(x0, x1);
         }
+        // Assumes x1 >= x0 && x0 > 0
         final double denom = shape * SQRT2;
         final double v0 = (Math.log(x0) - scale) / denom;
         final double v1 = (Math.log(x1) - scale) / denom;