2 arg - argument (the angle or phase) of a complex number
9 eps nonzero real, defaults to epsilon()
14 Returns the argument of x to the nearest or next to nearest multiple of
15 eps; the error will be less in absolute value than 0.75 * abs(eps),
16 but usually less than 0.5 * abs(eps).
19 > print arg(2), arg(2+3i, 1e-5), arg(2+3i, 1e-10), arg(2+3i, 1e-20)
20 0 .98279 .9827937232 .98279372324732906799
22 > pi = pi(1e-10); deg = pi/180; eps = deg/10000
23 > print arg(2+3i, eps)/deg, arg(-1 +1i, eps)/deg, arg(-1 - 1i,eps)/deg