public virtual void test_column() { double[][] @base = new double[][] { new double[] { 1d, 2d }, new double[] { 3d, 4d }, new double[] { 5d, 6d } }; DoubleMatrix test = DoubleMatrix.copyOf(@base); assertEquals(test.column(0), DoubleArray.of(1d, 3d, 5d)); assertEquals(test.column(1), DoubleArray.of(2d, 4d, 6d)); assertThrows(() => test.column(-1), typeof(System.IndexOutOfRangeException)); assertThrows(() => test.column(4), typeof(System.IndexOutOfRangeException)); }