Author: celestin
Date: Mon Nov 26 19:45:52 2012
New Revision: 1413802
URL: http://svn.apache.org/viewvc?rev=1413802&view=rev
Log:
MATH-849: Gamma.gamma(double) returns NaN if called on negative integer.
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/special/GammaTest.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java?rev=1413802&r1=1413801&r2=1413802&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/special/Gamma.java
Mon Nov 26 19:45:52 2012
@@ -706,7 +706,9 @@ public class Gamma {
*/
public static double gamma(final double x) {
- // TODO Check whether x is a negative integer
+ if ((x == FastMath.rint(x)) && (x <= 0.0)) {
+ return Double.NaN;
+ }
final double ret;
final double absX = FastMath.abs(x);
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/special/GammaTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math3/special/GammaTest.java?rev=1413802&r1=1413801&r2=1413802&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/special/GammaTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/special/GammaTest.java
Mon Nov 26 19:45:52 2012
@@ -954,6 +954,14 @@ public class GammaTest {
}
}
+ @Test
+ public void testGammaNegativeInteger() {
+
+ for (int i = -100; i <= 0; i++) {
+ Assert.assertTrue(Integer.toString(i),
Double.isNaN(Gamma.gamma(i)));
+ }
+ }
+
/**
* Reference data for the {@link Gamma#logGammaSum(double, double)}
* function. This data was generated with the following
