FUNCTION ALNREL(X)
C***BEGIN PROLOGUE  ALNREL
C***DATE WRITTEN   770401   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  C4B
C***KEYWORDS  ELEMENTARY FUNCTION,LOGARITHM,RELATIVE
C***AUTHOR  FULLERTON, W., (LANL)
C***PURPOSE  Evaluates ln(1+X) accurate in the sense of relative error.
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***REFERENCES  (NONE)
C***ROUTINES CALLED  CSEVL,INITS,R1MACH,XERROR
C***END PROLOGUE  ALNREL