SLATEC Routines --- DCHU ---

*DECK DCHU
      DOUBLE PRECISION FUNCTION DCHU (A, B, X)
C***BEGIN PROLOGUE  DCHU
C***PURPOSE  Compute the logarithmic confluent hypergeometric function.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C11
C***TYPE      DOUBLE PRECISION (CHU-S, DCHU-D)
C***KEYWORDS  FNLIB, LOGARITHMIC CONFLUENT HYPERGEOMETRIC FUNCTION,
C             SPECIAL FUNCTIONS
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C DCHU(A,B,X) calculates the double precision logarithmic confluent
C hypergeometric function U(A,B,X) for double precision arguments
C A, B, and X.
C
C This routine is not valid when 1+A-B is close to zero if X is small.
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  D1MACH, D9CHU, DEXPRL, DGAMMA, DGAMR, DPOCH,
C                    DPOCH1, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770801  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   900727  Added EXTERNAL statement.  (WRB)
C***END PROLOGUE  DCHU