COMPLEX FUNCTION CPSI(ZIN)
C***BEGIN PROLOGUE  CPSI
C***DATE WRITTEN   780501   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C7C
C***KEYWORDS  COMPLEX,DIGAMMA FUNCTION,PSI FUNCTION,SPECIAL FUNCTION
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Computes the Psi function of complex argument.
C***DESCRIPTION
C
C PSI(X) calculates the psi (or digamma) function of X.  PSI(X)
C is the logarithmic derivative of the gamma function of X.
C***REFERENCES  (NONE)
C***ROUTINES CALLED  CCOT,R1MACH,XERROR
C***END PROLOGUE  CPSI