*DECK CATANH
      COMPLEX FUNCTION CATANH (Z)
C***BEGIN PROLOGUE  CATANH
C***PURPOSE  Compute the arc hyperbolic tangent.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C4C
C***TYPE      COMPLEX (ATANH-S, DATANH-D, CATANH-C)
C***KEYWORDS  ARC HYPERBOLIC TANGENT, ATANH, ELEMENTARY FUNCTIONS,
C             FNLIB, INVERSE HYPERBOLIC TANGENT
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C CATANH(Z) calculates the complex arc hyperbolic tangent of Z.
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  CATAN
C***REVISION HISTORY  (YYMMDD)
C   770401  DATE WRITTEN
C   861211  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C***END PROLOGUE  CATANH
      COMPLEX Z, CI, CATAN
      SAVE CI
      DATA CI /(0.,1.)/
C***FIRST EXECUTABLE STATEMENT  CATANH
      CATANH = -CI*CATAN(CI*Z)
C
      RETURN
      END