anchor.diff:  C
   C LOG (ABS (DGAMMA(X)) ) FOR ABS(X) .LE. 10.0
   C
  -      DLNGAM = LOG (ABS (DGAMMA(X)) )
  +      DLNGAM = LOG (ABS (UTIL_DGAMMA(X)) )
         RETURN
   C
   C LOG ( ABS (DGAMMA(X)) ) FOR ABS(X) .GT. 10.0
  
positive.code: C   891214  Prologue converted to Version 4.0 format.  (BAB)
  C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
  C   920618  Removed space from variable name.  (RWC, WRB)
  C***END PROLOGUE  DGAMMA
        DOUBLE PRECISION X, GAMCS(42), DXREL, PI, SINPIY, SQ2PIL, XMAX,
       1  XMIN, Y, D9LGMC, DCSEVL, D1MACH
        LOGICAL FIRST
  
negative.code:       IF (X.LT.0.D0) N = N - 1
        Y = X - N
        N = N - 1
        UTIL_DGAMMA = 0.9375D0 + DCSEVL (2.D0*Y-1.D0, GAMCS, NGAM)
        IF (N.EQ.0) RETURN
  C
        IF (N.GT.0) GO TO 30
  