SLATEC Routines --- ATANH ---

*DECK ATANH
      FUNCTION ATANH (X)
C***BEGIN PROLOGUE  ATANH
C***PURPOSE  Compute the arc hyperbolic tangent.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C4C
C***TYPE      SINGLE PRECISION (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 ATANH(X) computes the arc hyperbolic tangent of X.
C
C Series for ATNH       on the interval  0.          to  2.50000D-01
C                                        with weighted error   6.70E-18
C                                         log weighted error  17.17
C                               significant figures required  16.01
C                                    decimal places required  17.76
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  CSEVL, INITS, R1MACH, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770401  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  ATANH