psteitz 2004/07/17 15:01:39
Modified: math/src/java/org/apache/commons/math/stat StatUtils.java
math/src/test/org/apache/commons/math/stat
StatUtilsTest.java
Log:
Added geometric mean to StatUtils.
Revision Changes Path
1.31 +46 -2
jakarta-commons/math/src/java/org/apache/commons/math/stat/StatUtils.java
Index: StatUtils.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/math/src/java/org/apache/commons/math/stat/StatUtils.java,v
retrieving revision 1.30
retrieving revision 1.31
diff -u -r1.30 -r1.31
--- StatUtils.java 11 Jul 2004 18:41:19 -0000 1.30
+++ StatUtils.java 17 Jul 2004 22:01:39 -0000 1.31
@@ -16,6 +16,7 @@
package org.apache.commons.math.stat;
import org.apache.commons.math.stat.univariate.UnivariateStatistic;
+import org.apache.commons.math.stat.univariate.moment.GeometricMean;
import org.apache.commons.math.stat.univariate.moment.Mean;
import org.apache.commons.math.stat.univariate.moment.Variance;
import org.apache.commons.math.stat.univariate.rank.Max;
@@ -58,8 +59,11 @@
/** variance */
private static Variance variance = new Variance();
- /** variance */
+ /** percentile */
private static Percentile percentile = new Percentile();
+
+ /** geometric mean */
+ private static GeometricMean geometricMean = new GeometricMean();
/**
* Private Constructor
@@ -246,6 +250,46 @@
final int length) {
return mean.evaluate(values, begin, length);
}
+
+ /**
+ * Returns the geometric mean of the entries in the input array, or
+ * <code>Double.NaN</code> if the array is empty.
+ * <p>
+ * Throws <code>IllegalArgumentException</code> if the array is null.
+ * <p>
+ * See [EMAIL PROTECTED]
org.apache.commons.math.stat.univariate.moment.GeometricMean}
+ * for details on the computing algorithm.
+ *
+ * @param values the input array
+ * @return the geometric mean of the values or Double.NaN if the array is empty
+ * @throws IllegalArgumentException if the array is null
+ */
+ public static double geometricMean(final double[] values) {
+ return geometricMean.evaluate(values);
+ }
+
+ /**
+ * Returns the geometric mean of the entries in the specified portion of
+ * the input array, or <code>Double.NaN</code> if the designated subarray
+ * is empty.
+ * <p>
+ * Throws <code>IllegalArgumentException</code> if the array is null.
+ * <p>
+ * See [EMAIL PROTECTED]
org.apache.commons.math.stat.univariate.moment.GeometricMean}
+ * for details on the computing algorithm.
+ *
+ * @param values the input array
+ * @param begin index of the first array element to include
+ * @param length the number of elements to include
+ * @return the geometric mean of the values or Double.NaN if length = 0
+ * @throws IllegalArgumentException if the array is null or the array index
+ * parameters are not valid
+ */
+ public static double geometricMean(final double[] values, final int begin,
+ final int length) {
+ return geometricMean.evaluate(values, begin, length);
+ }
+
/**
* Returns the variance of the entries in the input array, or
1.19 +14 -1
jakarta-commons/math/src/test/org/apache/commons/math/stat/StatUtilsTest.java
Index: StatUtilsTest.java
===================================================================
RCS file:
/home/cvs/jakarta-commons/math/src/test/org/apache/commons/math/stat/StatUtilsTest.java,v
retrieving revision 1.18
retrieving revision 1.19
diff -u -r1.18 -r1.19
--- StatUtilsTest.java 11 Jul 2004 18:42:07 -0000 1.18
+++ StatUtilsTest.java 17 Jul 2004 22:01:39 -0000 1.19
@@ -372,4 +372,17 @@
// expected
}
}
+
+ public void testGeometricMean() throws Exception {
+ double[] test = null;
+ try {
+ double x = StatUtils.geometricMean(test);
+ fail("Expecting IllegalArgumentException");
+ } catch (IllegalArgumentException ex) {
+ // expected
+ }
+ test = new double[] {2, 4, 6, 8};
+ assertEquals(Math.exp(0.25d * StatUtils.sumLog(test)),
+ StatUtils.geometricMean(test), Double.MIN_VALUE);
+ }
}
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
