Fixed accuracy of 3D Line.revert().

JIRA: MATH-938

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1453218 13f79535-47bb-0310-9956-ffa450edef68

src/changes/changes.xml

@@ -55,6 +55,9 @@ This is a minor release: It combines bug fixes and new features.
   Changes to existing features were made in a backwards-compatible
   way such as to allow drop-in replacement of the v3.1[.1] JAR file.
 ">
+      <action dev="luc" type="fix" issue="MATH-938" >
+        Fixed accuracy of 3D Line.revert().
+      </action>
       <action dev="luc" type="fix" issue="MATH-937" >
         Improved javadoc to explain how switching functions should
         behave across events in ODE events detection.

src/main/java/org/apache/commons/math3/geometry/euclidean/threed/Line.java

@@ -84,7 +84,9 @@ public void reset(final Vector3D p1, final Vector3D p2) throws MathIllegalArgume
      * @return a new instance, with reversed direction
      */
     public Line revert() {
-        return new Line(zero, zero.subtract(direction));
+        final Line reverted = new Line(this);
+        reverted.direction = reverted.direction.negate();
+        return reverted;
     }
 
     /** Get the normalized direction vector.

src/test/java/org/apache/commons/math3/geometry/euclidean/threed/LineTest.java

@@ -129,4 +129,20 @@ public void testIntersection() throws MathIllegalArgumentException {
         Assert.assertNull(l.intersection(new Line(new Vector3D(0, -4, 0), new Vector3D(1, -4, 0))));
     }
 
+    @Test
+    public void testRevert() {
+
+        // setup
+        Line line = new Line(new Vector3D(1653345.6696423641, 6170370.041579291, 90000),
+                             new Vector3D(1650757.5050732433, 6160710.879908984, 0.9));
+        Vector3D expected = line.getDirection().negate();
+
+        // action
+        Line reverted = line.revert();
+
+        // verify
+        Assert.assertArrayEquals(expected.toArray(), reverted.getDirection().toArray(), 0);
+
+    }
+
 }