public virtual void test_columnArray()
        {
            double[][] @base = new double[][]
            {
                new double[] { 1d, 2d },
                new double[] { 3d, 4d },
                new double[] { 5d, 6d }
            };
            DoubleMatrix test = DoubleMatrix.copyOf(@base);

            assertEquals(test.columnArray(0), new double[] { 1d, 3d, 5d });
            assertEquals(test.columnArray(1), new double[] { 2d, 4d, 6d });
            assertThrows(() => test.columnArray(-1), typeof(System.IndexOutOfRangeException));
            assertThrows(() => test.columnArray(4), typeof(System.IndexOutOfRangeException));
        }