mdiggory 2003/06/17 16:23:07
Modified: math/src/java/org/apache/commons/math/stat StatUtils.java
Log:
Addition of product and geometericMean.
Revision Changes Path
1.3 +26 -0
jakarta-commons-sandbox/math/src/java/org/apache/commons/math/stat/StatUtils.java
Index: StatUtils.java
===================================================================
RCS file:
/home/cvs/jakarta-commons-sandbox/math/src/java/org/apache/commons/math/stat/StatUtils.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- StatUtils.java 17 Jun 2003 23:00:17 -0000 1.2
+++ StatUtils.java 17 Jun 2003 23:23:07 -0000 1.3
@@ -88,6 +88,32 @@
return accum;
}
+ /**
+ * Returns the product for this collection of values
+ * @param values Is a double[] containing the values
+ * @return the product values or Double.NaN if the array is empty
+ */
+ public static double product(double[] values) {
+ double product = Double.NaN;
+ if( values.length > 0 ) {
+ product = 1.0;
+ for( int i = 0; i < values.length; i++) {
+ product *= values[i];
+ }
+ }
+ return product;
+ }
+
+ /**
+ * Returns the geometric mean for this collection of values
+ * @param values Is a double[] containing the values
+ * @return the geometric mean or Double.NaN if the array is empty or
+ * any of the values are <= 0.
+ */
+ public static double geometricMean(double[] values) {
+ return Math.pow(product(values),(1.0/values.length));
+ }
+
/**
* Returns the <a href=http://www.xycoon.com/arithmetic_mean.htm>
* arithmetic mean </a> of the available values
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