@Test
public void testCrossProduct() {

  Matrix result = test.cross(test);
  assertEquals("row size", test.size(), result.rowSize());
  assertEquals("col size", test.size(), result.columnSize());
  for (int row = 0; row < result.rowSize(); row++) {
    for (int col = 0; col < result.columnSize(); col++) {
      assertEquals("cross[" + row + "][" + col + ']', test.getQuick(row)
          * test.getQuick(col), result.getQuick(row, col), EPSILON);
    }
  }
}