public static Complex of(double real) {
        return new Complex(real, 0.0);
    }
@Test
    public void testArray() {
        System.out.println("Complex.Array");
        Complex.Array array = Complex.Array.of(a, b);
        System.out.println("a = " + a);
        System.out.println("b = " + b);
        assertEquals(a.re, array.get(0).re, 1E-15);
        assertEquals(a.im, array.get(0).im, 1E-15);
        assertEquals(b.re, array.get(1).re, 1E-15);
        assertEquals(b.im, array.get(1).im, 1E-15);

        Complex c = Complex.of(3.0);
        array.set(1, c);
        assertEquals(a.re, array.get(0).re, 1E-15);
        assertEquals(a.im, array.get(0).im, 1E-15);
        assertEquals(c.re, array.get(1).re, 1E-15);
        assertEquals(c.im, array.get(1).im, 1E-15);
    }