svn commit: r1520619 - in /commons/proper/math/trunk/src: main/java/org/apache/commons/math3/util/MathArrays.java test/java/org/apache/commons/math3/util/MathArraysTest.java

[erans]

Author: erans
Date: Fri Sep  6 16:05:51 2013
New Revision: 1520619

URL: http://svn.apache.org/r1520619
Log:
Created "natural" method in "MathArrays" from code previously in
class "RandomDataGenerator" (private method).

Modified:
    
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java
    
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/MathArraysTest.java

Modified: 
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java
URL: 
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java?rev=1520619&r1=1520618&r2=1520619&view=diff
==============================================================================
--- 
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java
 (original)
+++ 
commons/proper/math/trunk/src/main/java/org/apache/commons/math3/util/MathArrays.java
 Fri Sep  6 16:05:51 2013
@@ -1533,4 +1533,19 @@ public class MathArrays {
     public static void shuffle(int[] list) {
         shuffle(list, new Well19937c());
     }
+
+    /**
+     * Returns an array representing the natural number {@code n}.
+     *
+     * @param n Natural number.
+     * @return an array whose entries are the numbers 0, 1, ..., {@code n}-1.
+     * If {@code n == 0}, the returned array is empty.
+     */
+    public static int[] natural(int n) {
+        final int[] a = new int[n];
+        for (int i = 0; i < n; i++) {
+            a[i] = i;
+        }
+        return a;
+    }
 }

Modified: 
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/MathArraysTest.java
URL: 
http://svn.apache.org/viewvc/commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/MathArraysTest.java?rev=1520619&r1=1520618&r2=1520619&view=diff
==============================================================================
--- 
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/MathArraysTest.java
 (original)
+++ 
commons/proper/math/trunk/src/test/java/org/apache/commons/math3/util/MathArraysTest.java
 Fri Sep  6 16:05:51 2013
@@ -979,4 +979,21 @@ public class MathArraysTest {
         }
         Assert.assertTrue(ok);
     }
+
+    @Test
+    public void testNatural() {
+        final int n = 4;
+        final int[] expected = {0, 1, 2, 3};
+
+        final int[] natural = MathArrays.natural(n);
+        for (int i = 0; i < n; i++) {
+            Assert.assertEquals(expected[i], natural[i]);
+        }
+    }
+
+    @Test
+    public void testNaturalZero() {
+        final int[] natural = MathArrays.natural(0);
+        Assert.assertEquals(natural.length, 0);
+    }
 }