# chu.f

          FUNCTION CHU (A, B, X)
    C***BEGIN PROLOGUE  CHU
    C***PURPOSE  Compute the logarithmic confluent hypergeometric function.
    C***LIBRARY   SLATEC (FNLIB)
    C***CATEGORY  C11
    C***TYPE      SINGLE PRECISION (CHU-S, DCHU-D)
    C***KEYWORDS  FNLIB, LOGARITHMIC CONFLUENT HYPERGEOMETRIC FUNCTION,
    C             SPECIAL FUNCTIONS
    C***AUTHOR  Fullerton, W., (LANL)
    C***DESCRIPTION
    C
    C CHU computes the logarithmic confluent hypergeometric function,
    C U(A,B,X).
    C
    C Input Parameters:
    C       A   real
    C       B   real
    C       X   real and positive
    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  EXPREL, GAMMA, GAMR, POCH, POCH1, R1MACH, R9CHU,
    C                    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  CHU