X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=test%2Fjalview%2Fmath%2FRotatableMatrixTest.java;fp=test%2Fjalview%2Fmath%2FRotatableMatrixTest.java;h=06982d52322971620dc20e242594bcc0d879a091;hb=aace9d05c0870c703bfdfb28c1608213cee019bf;hp=0000000000000000000000000000000000000000;hpb=2a3bac30ae8290e912eb7ffe7ff7ec700b6cfaac;p=jalview.git

diff --git a/test/jalview/math/RotatableMatrixTest.java b/test/jalview/math/RotatableMatrixTest.java
new file mode 100644
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--- /dev/null
+++ b/test/jalview/math/RotatableMatrixTest.java
@@ -0,0 +1,157 @@
+package jalview.math;
+
+import static org.testng.Assert.assertEquals;
+
+import jalview.math.RotatableMatrix.Axis;
+
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Test;
+
+public class RotatableMatrixTest
+{
+  private RotatableMatrix rm;
+
+  @BeforeMethod(alwaysRun = true)
+  public void setUp()
+  {
+    rm = new RotatableMatrix();
+
+    /*
+     * 0.5 1.0 1.5
+     * 1.0 2.0 3.0
+     * 1.5 3.0 4.5
+     */
+    for (int i = 1; i <= 3; i++)
+    {
+      for (int j = 1; j <= 3; j++)
+      {
+        rm.setValue(i - 1, j - 1, i * j / 2f);
+      }
+    }
+  }
+
+  @Test(groups = "Functional")
+  public void testPreMultiply()
+  {
+    float[][] pre = new float[3][3];
+    int i = 1;
+    for (int j = 0; j < 3; j++)
+    {
+      for (int k = 0; k < 3; k++)
+      {
+        pre[j][k] = i++;
+      }
+    }
+
+    rm.preMultiply(pre);
+
+    /*
+     * check rm[i, j] is now the product of the i'th row of pre
+     * and the j'th column of (original) rm
+     */
+    for (int j = 0; j < 3; j++)
+    {
+      for (int k = 0; k < 3; k++)
+      {
+        float expected = 0f;
+        for (int l = 0; l < 3; l++)
+        {
+          float rm_l_k = (l + 1) * (k + 1) / 2f;
+          expected += pre[j][l] * rm_l_k;
+        }
+        assertEquals(rm.getValue(j, k), expected,
+                String.format("[%d, %d]", j, k));
+      }
+    }
+  }
+
+  @Test(groups = "Functional")
+  public void testVectorMultiply()
+  {
+    float[] result = rm.vectorMultiply(new float[] { 2f, 3f, 4.5f });
+
+    // vector times first column of matrix
+    assertEquals(result[0], 2f * 0.5f + 3f * 1f + 4.5f * 1.5f);
+
+    // vector times second column of matrix
+    assertEquals(result[1], 2f * 1.0f + 3f * 2f + 4.5f * 3f);
+
+    // vector times third column of matrix
+    assertEquals(result[2], 2f * 1.5f + 3f * 3f + 4.5f * 4.5f);
+  }
+
+  @Test(groups = "Functional")
+  public void testGetRotation()
+  {
+    float theta = 60f;
+    double cosTheta = Math.cos((theta * Math.PI / 180f));
+    double sinTheta = Math.sin((theta * Math.PI / 180f));
+
+    /*
+     * sanity check that sin(60) = sqrt(3) / 2, cos(60) = 1/2
+     */
+    double delta = 0.0001d;
+    assertEquals(cosTheta, 0.5f, delta);
+    assertEquals(sinTheta, Math.sqrt(3d) / 2d, delta);
+
+    /*
+     * so far so good, now verify rotations
+     * @see https://en.wikipedia.org/wiki/Rotation_matrix#Basic_rotations
+     */
+
+    /*
+     * 60 degrees about X axis should be
+     *  1   0   0 
+     *  0  cos -sin
+     *  0  sin cos
+     *  but code applies the negative of this
+     *  nb cos(-x) = cos(x), sin(-x) = -sin(x)
+     */
+    float[][] rot = RotatableMatrix.getRotation(theta, Axis.X);
+    assertEquals(rot[0][0], 1f, delta);
+    assertEquals(rot[0][1], 0f, delta);
+    assertEquals(rot[0][2], 0f, delta);
+    assertEquals(rot[1][0], 0f, delta);
+    assertEquals(rot[1][1], cosTheta, delta);
+    assertEquals(rot[1][2], sinTheta, delta);
+    assertEquals(rot[2][0], 0f, delta);
+    assertEquals(rot[2][1], -sinTheta, delta);
+    assertEquals(rot[2][2], cosTheta, delta);
+
+    /*
+     * 60 degrees about Y axis should be
+     *   cos 0 sin
+     *    0  1  0
+     *  -sin 0 cos
+     *  but code applies the negative of this
+     */
+    rot = RotatableMatrix.getRotation(theta, Axis.Y);
+    assertEquals(rot[0][0], cosTheta, delta);
+    assertEquals(rot[0][1], 0f, delta);
+    assertEquals(rot[0][2], -sinTheta, delta);
+    assertEquals(rot[1][0], 0f, delta);
+    assertEquals(rot[1][1], 1f, delta);
+    assertEquals(rot[1][2], 0f, delta);
+    assertEquals(rot[2][0], sinTheta, delta);
+    assertEquals(rot[2][1], 0f, delta);
+    assertEquals(rot[2][2], cosTheta, delta);
+
+    /*
+     * 60 degrees about Z axis should be
+     *  cos -sin 0
+     *  sin  cos 0
+     *   0    0  1
+     * - and it is!
+     */
+    rot = RotatableMatrix.getRotation(theta, Axis.Z);
+    assertEquals(rot[0][0], cosTheta, delta);
+    assertEquals(rot[0][1], -sinTheta, delta);
+    assertEquals(rot[0][2], 0f, delta);
+    assertEquals(rot[1][0], sinTheta, delta);
+    assertEquals(rot[1][1], cosTheta, delta);
+    assertEquals(rot[1][2], 0f, delta);
+    assertEquals(rot[2][0], 0f, delta);
+    assertEquals(rot[2][1], 0f, delta);
+    assertEquals(rot[2][2], 1f, delta);
+  }
+}