# catan.f

          COMPLEX FUNCTION CATAN (Z)
    C***BEGIN PROLOGUE  CATAN
    C***PURPOSE  Compute the complex arc tangent.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C4A
    C***TYPE      COMPLEX (CATAN-C)
    C***KEYWORDS  ARC TANGENT, ELEMENTARY FUNCTIONS, FNLIB, TRIGONOMETRIC
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C CATAN(Z) calculates the complex trigonometric arc tangent of Z.
    C The result is in units of radians, and the real part is in the first
    C or fourth quadrant.
    C
    C***REFERENCES  (NONE)
    C***ROUTINES CALLED  R1MACH, XERMSG
    C***REVISION HISTORY  (YYMMDD)
    C   770801  DATE WRITTEN
    C   890531  Changed all specific intrinsics to generic.  (WRB)
    C   890531  REVISION DATE from Version 3.2
    C   891214  Prologue converted to Version 4.0 format.  (BAB)
    C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
    C   900326  Removed duplicate information from DESCRIPTION section.
    C           (WRB)
    C***END PROLOGUE  CATAN