Use static methods if possible
diff --git a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/HypergeometricDistribution.java b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/HypergeometricDistribution.java
index 22b8895..cdeab67 100644
--- a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/HypergeometricDistribution.java
+++ b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/HypergeometricDistribution.java
@@ -94,7 +94,7 @@
* @return a two element array containing the lower and upper bounds of the
* hypergeometric distribution.
*/
- private int[] getDomain(int n, int m, int k) {
+ private static int[] getDomain(int n, int m, int k) {
return new int[] {getLowerDomain(n, m, k), getUpperDomain(m, k)};
}
@@ -107,7 +107,7 @@
* @param k Sample size.
* @return the lowest domain value of the hypergeometric distribution.
*/
- private int getLowerDomain(int n, int m, int k) {
+ private static int getLowerDomain(int n, int m, int k) {
return Math.max(0, m - (n - k));
}
@@ -146,7 +146,7 @@
* @param k Sample size.
* @return the highest domain value of the hypergeometric distribution.
*/
- private int getUpperDomain(int m, int k) {
+ private static int getUpperDomain(int m, int k) {
return Math.min(k, m);
}
diff --git a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/ZipfDistribution.java b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/ZipfDistribution.java
index c104438..389feb3 100644
--- a/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/ZipfDistribution.java
+++ b/commons-statistics-distribution/src/main/java/org/apache/commons/statistics/distribution/ZipfDistribution.java
@@ -171,7 +171,7 @@
* @param m Exponent (special case {@code m = 1} is the harmonic series).
* @return the n<sup>th</sup> generalized harmonic number.
*/
- private double generalizedHarmonic(final int n, final double m) {
+ private static double generalizedHarmonic(final int n, final double m) {
double value = 0;
for (int k = n; k > 0; --k) {
value += 1 / Math.pow(k, m);
