DOUBLE PRECISION FUNCTION DPSI(X)
C***BEGIN PROLOGUE  DPSI
C***DATE WRITTEN   770601   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C7C
C***KEYWORDS  DIGAMMA FUNCTION,DOUBLE PRECISION,PSI FUNCTION,
C             SPECIAL FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the d.p. Psi (or Digamma) function.
C***DESCRIPTION
C
C DPSI calculates the double precision psi (or digamma) function for
C double precision argument X.  PSI(X) is the logarithmic derivative
C of the gamma function of X.
C
C Series for PSI        on the interval  0.          to  1.00000E+00
C                                        with weighted error   5.79E-32
C                                         log weighted error  31.24
C                               significant figures required  30.93
C                                    decimal places required  32.05
C
C
C Series for APSI       on the interval  0.          to  1.00000E-02
C                                        with weighted error   7.75E-33
C                                         log weighted error  32.11
C                               significant figures required  28.88
C                                    decimal places required  32.71
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH,DCOT,DCSEVL,DINT,INITDS,XERROR
C***END PROLOGUE  DPSI