Author: psteitz
Date: Sat May 14 18:51:26 2011
New Revision: 1103182
URL: http://svn.apache.org/viewvc?rev=1103182&view=rev
Log:
Improved javadoc and added infinite/NaN argument tests for reduce.
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
Modified:
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java?rev=1103182&r1=1103181&r2=1103182&view=diff
==============================================================================
---
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
(original)
+++
commons/proper/math/trunk/src/main/java/org/apache/commons/math/util/MathUtils.java
Sat May 14 18:51:26 2011
@@ -1282,12 +1282,19 @@ public final class MathUtils {
}
/**
- * Reduce to the primary interval {@code [0 period)}.
+ * <p>Reduce {@code |a - offset|} to the primary interval
+ * {@code [0, |period|)}.</p>
+ *
+ * <p>Specifically, the value returned is <br/>
+ * {@code a - |period| * floor((a - offset) / |period|) - offset}.</p>
+ *
+ * <p>If any of the parameters are {@code NaN} or infinite, the result is
+ * {@code NaN}.</p>
*
* @param a Value to reduce.
* @param period Period.
* @param offset Value that will be mapped to {@code 0}.
- * @return the value, within the interval {@code [0 period)},
+ * @return the value, within the interval {@code [0 |period|)},
* that corresponds to {@code a}.
*/
public static double reduce(double a,
Modified:
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
URL:
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java?rev=1103182&r1=1103181&r2=1103182&view=diff
==============================================================================
---
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
(original)
+++
commons/proper/math/trunk/src/test/java/org/apache/commons/math/util/MathUtilsTest.java
Sat May 14 18:51:26 2011
@@ -1086,6 +1086,24 @@ public final class MathUtilsTest {
Assert.assertEquals(expected,
MathUtils.reduce(orig, -period, offset),
1e-6);
+
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(orig, Double.NaN,
offset)));
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(Double.NaN, period,
offset)));
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(orig, period,
Double.NaN)));
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(orig, period,
+ Double.POSITIVE_INFINITY)));
+
Assert.assertTrue(Double.isNaN(MathUtils.reduce(Double.POSITIVE_INFINITY,
+ period, offset)));
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(orig,
+ Double.POSITIVE_INFINITY, offset)));
+ Assert.assertTrue(Double.isNaN(MathUtils.reduce(orig,
+ Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY)));
+
Assert.assertTrue(Double.isNaN(MathUtils.reduce(Double.POSITIVE_INFINITY,
+ period, Double.POSITIVE_INFINITY)));
+
Assert.assertTrue(Double.isNaN(MathUtils.reduce(Double.POSITIVE_INFINITY,
+ Double.POSITIVE_INFINITY, offset)));
+
Assert.assertTrue(Double.isNaN(MathUtils.reduce(Double.POSITIVE_INFINITY,
+ Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY)));
}
@Test
