[cacosresult,z]=cacos(z);

function [cacosresult,z]=cacos(z);
cacosresult=[];
persistent firstCall pi2 ; if isempty(firstCall),firstCall=1;end; 

;
if isempty(pi2), pi2=0; end;
%***BEGIN PROLOGUE  CACOS
%***PURPOSE  Compute the complex arc cosine.
%***LIBRARY   SLATEC (FNLIB)
%***CATEGORY  C4A
%***TYPE      COMPLEX (CACOS-C)
%***KEYWORDS  ARC COSINE, ELEMENTARY FUNCTIONS, FNLIB, TRIGONOMETRIC
%***AUTHOR  Fullerton, W., (LANL)
%***DESCRIPTION
%
% CACOS(Z) calculates the complex trigonometric arc cosine of Z.
% The result is in units of radians, and the real part is in the
% first or second quadrant.
%
%***REFERENCES  (NONE)
%***ROUTINES CALLED  CASIN
%***REVISION HISTORY  (YYMMDD)
%   770401  DATE WRITTEN
%   861211  REVISION DATE from Version 3.2
%   891214  Prologue converted to Version 4.0 format.  (BAB)
%***end PROLOGUE  CACOS
if firstCall,   pi2=[1.57079632679489661923e0];  end;
firstCall=0;
%***FIRST EXECUTABLE STATEMENT  CACOS
cacosresult = pi2 - casin(z);
%
csnil=dbstack(1); csnil=csnil(1).name(1)~='@';
if csnil&&~isempty(inputname(1)), assignin('caller','FUntemp',z); evalin('caller',[inputname(1),'=FUntemp;']); end
end
%DECK CACOSH