Added applyTo and applyInverseTo methods in the Rotation class that

handle directly arrays instead of Vector3D instances.

Patch provided by Jan Kotek.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/math/trunk@1200545 13f79535-47bb-0310-9956-ffa450edef68

src/main/java/org/apache/commons/math/geometry/euclidean/threed/Rotation.java

@@ -847,6 +847,25 @@ public class Rotation implements Serializable {
 
   }
 
+  /** Apply the rotation to a vector stored in an array.
+   * @param in an array with three items which stores vector to rotate
+   * @param out an array with three items to put result to (it can be the same
+   * array as in)
+   */
+  public void applyTo(final double[] in, final double[] out) {
+
+      final double x = in[0];
+      final double y = in[1];
+      final double z = in[2];
+
+      final double s = q1 * x + q2 * y + q3 * z;
+
+      out[0] = 2 * (q0 * (x * q0 - (q2 * z - q3 * y)) + s * q1) - x;
+      out[1] = 2 * (q0 * (y * q0 - (q3 * x - q1 * z)) + s * q2) - y;
+      out[2] = 2 * (q0 * (z * q0 - (q1 * y - q2 * x)) + s * q3) - z;
+
+  }
+
   /** Apply the inverse of the rotation to a vector.
    * @param u vector to apply the inverse of the rotation to
    * @return a new vector which such that u is its image by the rotation
@@ -866,6 +885,26 @@ public class Rotation implements Serializable {
 
   }
 
+  /** Apply the inverse of the rotation to a vector stored in an array.
+   * @param in an array with three items which stores vector to rotate
+   * @param out an array with three items to put result to (it can be the same
+   * array as in)
+   */
+  public void applyInverseTo(final double[] in, final double[] out) {
+
+      final double x = in[0];
+      final double y = in[1];
+      final double z = in[2];
+
+      final double s = q1 * x + q2 * y + q3 * z;
+      final double m0 = -q0;
+
+      out[0] = 2 * (m0 * (x * m0 - (q2 * z - q3 * y)) + s * q1) - x;
+      out[1] = 2 * (m0 * (y * m0 - (q3 * x - q1 * z)) + s * q2) - y;
+      out[2] = 2 * (m0 * (z * m0 - (q1 * y - q2 * x)) + s * q3) - z;
+
+  }
+
   /** Apply the instance to another rotation.
    * Applying the instance to a rotation is computing the composition
    * in an order compliant with the following rule : let u be any

src/site/xdoc/changes.xml

@@ -52,6 +52,10 @@ The <action> type attribute can be add,update,fix,remove.
     If the output is not quite correct, check for invisible trailing spaces!
      -->
     <release version="3.0" date="TBD" description="TBD">
+      <action dev="luc" type="add" due-to="Jan Kotek" >
+        Added applyTo and applyInverseTo methods in the Rotation class that
+        handle directly arrays instead of Vector3D instances.
+      </action>
       <action dev="luc" type="fix" issue="MATH-196" >
         Added adapters for simple bound constraints optimization that can be
         used for all direct optimization methods, including the ones that do not

src/test/java/org/apache/commons/math/geometry/euclidean/threed/RotationTest.java

@@ -438,6 +438,31 @@ public class RotationTest {
 
   }
 
+  @Test
+  public void testArray() {
+
+      Rotation r = new Rotation(new Vector3D(2, -3, 5), 1.7);
+
+      for (double x = -0.9; x < 0.9; x += 0.2) {
+          for (double y = -0.9; y < 0.9; y += 0.2) {
+              for (double z = -0.9; z < 0.9; z += 0.2) {
+                  Vector3D u = new Vector3D(x, y, z);
+                  Vector3D v = r.applyTo(u);
+                  double[] inOut = new double[] { x, y, z };
+                  r.applyTo(inOut, inOut);
+                  Assert.assertEquals(v.getX(), inOut[0], 1.0e-10);
+                  Assert.assertEquals(v.getY(), inOut[1], 1.0e-10);
+                  Assert.assertEquals(v.getZ(), inOut[2], 1.0e-10);
+                  r.applyInverseTo(inOut, inOut);
+                  Assert.assertEquals(u.getX(), inOut[0], 1.0e-10);
+                  Assert.assertEquals(u.getY(), inOut[1], 1.0e-10);
+                  Assert.assertEquals(u.getZ(), inOut[2], 1.0e-10);
+              }
+          }
+      }
+
+  }
+
   @Test
   public void testApplyInverseTo() {