*DECK ALNREL
      FUNCTION ALNREL (X)
C***BEGIN PROLOGUE  ALNREL
C***PURPOSE  Evaluate ln(1+X) accurate in the sense of relative error.
C***LIBRARY   SLATEC (FNLIB)
C***CATEGORY  C4B
C***TYPE      SINGLE PRECISION (ALNREL-S, DLNREL-D, CLNREL-C)
C***KEYWORDS  ELEMENTARY FUNCTIONS, FNLIB, LOGARITHM
C***AUTHOR  Fullerton, W., (LANL)
C***DESCRIPTION
C
C ALNREL(X) evaluates ln(1+X) accurately in the sense of relative
C error when X is very small.  This routine must be used to
C maintain relative error accuracy whenever X is small and
C accurately known.
C
C Series for ALNR       on the interval -3.75000D-01 to  3.75000D-01
C                                        with weighted error   1.93E-17
C                                         log weighted error  16.72
C                               significant figures required  16.44
C                                    decimal places required  17.40
C
C***REFERENCES  (NONE)
C***ROUTINES CALLED  CSEVL, INITS, R1MACH, XERMSG
C***REVISION HISTORY  (YYMMDD)
C   770401  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   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C***END PROLOGUE  ALNREL