SLATEC Routines --- DFAC ---

*DECK DFAC
      DOUBLE PRECISION FUNCTION DFAC (N)
C***BEGIN PROLOGUE  DFAC
C***PURPOSE  Compute the factorial function.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C1
C***TYPE      DOUBLE PRECISION (FAC-S, DFAC-D)
C***KEYWORDS  FACTORIAL, FNLIB, SPECIAL FUNCTIONS
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C DFAC(N) calculates the double precision factorial for integer
C argument N.
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D9LGMC, DGAMLM, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770601  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***END PROLOGUE  DFAC