ALNREL(3)

SYNOPSIS
FUNCTION ALNREL (X)

NAME
alnrel - Evaluate ln(1+X) accurate in the sense of relative error.

LIBRARY
SLATEC (FNLIB)

CATEGORY
C4B

TYPE
SINGLE PRECISION (ALNREL-S, DLNREL-D, CLNREL-C)

KEYWORDS
ELEMENTARY FUNCTIONS, FNLIB, LOGARITHM

AUTHOR
Fullerton, W., (LANL)

DESCRIPTION
ALNREL(X) evaluates ln(1+X) accurately in the sense of relative error when X is very small. This routine must be used to maintain relative error accuracy whenever X is small and accurately known. Series for ALNR on the interval -3.75000D-01 to 3.75000D-01 with weighted error 1.93E-17 log weighted error 16.72 significant figures required 16.44 decimal places required 17.40

REFERENCES
(NONE)

ROUTINES CALLED
CSEVL, INITS, R1MACH, XERMSG

REVISION HISTORY (YYMMDD)
770401 DATE WRITTEN
890531 Changed all specific intrinsics to generic. (WRB)
890531 REVISION DATE from Version 3.2
891214 Prologue converted to Version 4.0 format. (BAB)
900315 CALLs to XERROR changed to CALLs to XERMSG. (THJ)
900326 Removed duplicate information from DESCRIPTION section. (WRB)