clog-Complex Natural Logarithm

F_COMPLEX clog (F_TYPE x, F_TYPE y)

clog() returns the natural logarithm of a complex number.

clog(x,y) is defined as ln(x + iy) = 1/2 ln(x**2 + y**2) + iatan2 (y,x).

Exceptional Argument       Routine Behavior

y=x=0                      Invalid argument

|y|=|x|=infinity           Invalid argument