[commons-math] branch master updated: MATH-1401: Branch added to prevent passing invalid input to "FDistribution".

[erans]

This is an automated email from the ASF dual-hosted git repository.

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


The following commit(s) were added to refs/heads/master by this push:
     new 53d9c7f  MATH-1401: Branch added to prevent passing invalid input to 
"FDistribution".
53d9c7f is described below

commit 53d9c7fbfbe9cbd7e11cb872ef87e00462fa3eca
Author: Gilles Sadowski <gil...@harfang.homelinux.org>
AuthorDate: Tue Apr 16 12:54:04 2019 +0200

    MATH-1401: Branch added to prevent passing invalid input to "FDistribution".
    
    Thanks to Michele De Stefano for circumscribing the issue.
---
 src/changes/changes.xml                                    |  3 +++
 .../math4/stat/interval/ClopperPearsonInterval.java        | 14 +++++++++-----
 .../math4/stat/interval/ClopperPearsonIntervalTest.java    |  6 ++++++
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 2401282..8b5f8e5 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -54,6 +54,9 @@ If the output is not quite correct, check for invisible 
trailing spaces!
     </release>
 
     <release version="4.0" date="XXXX-XX-XX" description="">
+      <action dev="erans" type="fix" issue="MATH-1401">
+        "ClopperPearsonInterval": Fixed case where number of trials equals 
number of successes.
+      </action>
       <action dev="erans" type="add" issue="MATH-1477" due-to="Chee Sing Lee">
         "MillerUpdatingRegression": Fixed "ArrayIndexOutOfBounds" exception.
       </action>
diff --git 
a/src/main/java/org/apache/commons/math4/stat/interval/ClopperPearsonInterval.java
 
b/src/main/java/org/apache/commons/math4/stat/interval/ClopperPearsonInterval.java
index b6a72ff..5bf642c 100644
--- 
a/src/main/java/org/apache/commons/math4/stat/interval/ClopperPearsonInterval.java
+++ 
b/src/main/java/org/apache/commons/math4/stat/interval/ClopperPearsonInterval.java
@@ -46,11 +46,15 @@ public class ClopperPearsonInterval implements 
BinomialConfidenceInterval {
             lowerBound = numberOfSuccesses /
                 (numberOfSuccesses + (numberOfTrials - numberOfSuccesses + 1) 
* fValueLowerBound);
 
-            final FDistribution distributionUpperBound = new FDistribution(2 * 
(numberOfSuccesses + 1),
-                                                                           2 * 
(numberOfTrials - numberOfSuccesses));
-            final double fValueUpperBound = 
distributionUpperBound.inverseCumulativeProbability(1 - alpha);
-            upperBound = (numberOfSuccesses + 1) * fValueUpperBound /
-                (numberOfTrials - numberOfSuccesses + (numberOfSuccesses + 1) 
* fValueUpperBound);
+            if (numberOfSuccesses != numberOfTrials) {
+                final FDistribution distributionUpperBound = new 
FDistribution(2 * (numberOfSuccesses + 1),
+                                                                               
2 * (numberOfTrials - numberOfSuccesses));
+                final double fValueUpperBound = 
distributionUpperBound.inverseCumulativeProbability(1 - alpha);
+                upperBound = (numberOfSuccesses + 1) * fValueUpperBound /
+                    (numberOfTrials - numberOfSuccesses + (numberOfSuccesses + 
1) * fValueUpperBound);
+            } else {
+                upperBound = 1;
+            }
         }
 
         return new ConfidenceInterval(lowerBound, upperBound, confidenceLevel);
diff --git 
a/src/test/java/org/apache/commons/math4/stat/interval/ClopperPearsonIntervalTest.java
 
b/src/test/java/org/apache/commons/math4/stat/interval/ClopperPearsonIntervalTest.java
index e50ab58..a8a1db1 100644
--- 
a/src/test/java/org/apache/commons/math4/stat/interval/ClopperPearsonIntervalTest.java
+++ 
b/src/test/java/org/apache/commons/math4/stat/interval/ClopperPearsonIntervalTest.java
@@ -40,4 +40,10 @@ public class ClopperPearsonIntervalTest extends 
BinomialConfidenceIntervalAbstra
         Assert.assertEquals(0.1248658, confidenceInterval.getUpperBound(), 
1E-5);
     }
 
+    @Test
+    public void testMath1401() {
+        ConfidenceInterval interval = new 
ClopperPearsonInterval().createInterval(1, 1, 0.95);
+        Assert.assertEquals(0.025, interval.getLowerBound(), 1e-16);
+        Assert.assertEquals(1, interval.getUpperBound(), 0d);
+    }
 }