    const std = @import("../../std.zig");
    const testing = std.testing;
    const math = std.math;
    const cmath = math.complex;
    const Complex = cmath.Complex;

    /// Returns the natural logarithm of z.
    pub fn log(z: anytype) Complex(@TypeOf(z.re)) {
        const T = @TypeOf(z.re);
        const r = cmath.abs(z);
        const phi = cmath.arg(z);

        return Complex(T).init(@log(r), phi);
    }

    const epsilon = 0.0001;

    test "complex.clog" {
        const a = Complex(f32).init(5, 3);
        const c = log(a);

        try testing.expect(math.approxEqAbs(f32, c.re, 1.763180, epsilon));
        try testing.expect(math.approxEqAbs(f32, c.im, 0.540419, epsilon));
    }