CATAN.EXP

(* @NESTEDCOMMENTS := 'Yes' *)
(* @PATH := '\/Mathematical\/Complex' *)
(* @OBJECTFLAGS := '0, 8' *)
(* @SYMFILEFLAGS := '2048' *)
FUNCTION CATAN : complex
VAR_INPUT
	X : complex;
END_VAR
VAR
	r2: REAL;
	num, den : REAL;
END_VAR

(*
version 1.0	21 feb 2008
programmer 	hugo
tested by	oscat

this function calculates the complex arcus tangens

*)
(* @END_DECLARATION := '0' *)
r2 := x.re * x.re;
den := 1.0 - r2 - x.im * x.im;
CATAN.re := 0.5 * ATAN(2.0 * x.re / den);
num := x.im + 1.0;
num := r2 + num * num;
den := x.im - 1.0;
den := r2 + den * den;
CATAN.im := 0.25 * (LN(num)-LN(den));

(* revision history
hm	21. feb 2008	rev 1.0
	original version


*)
END_FUNCTION