dlnrel.f
DOUBLE PRECISION FUNCTION DLNREL (X)
C***BEGIN PROLOGUE DLNREL
C***PURPOSE Evaluate ln(1+X) accurate in the sense of relative error.
C***LIBRARY SLATEC (FNLIB)
C***CATEGORY C4B
C***TYPE DOUBLE PRECISION (ALNREL-S, DLNREL-D, CLNREL-C)
C***KEYWORDS ELEMENTARY FUNCTIONS, FNLIB, LOGARITHM
C***AUTHOR Fullerton, W., (LANL)
C***DESCRIPTION
C
C DLNREL(X) calculates the double precision natural logarithm of
C (1.0+X) for double precision argument X. This routine should
C be used when X is small and accurate to calculate the logarithm
C accurately (in the relative error sense) in the neighborhood
C of 1.0.
C
C Series for ALNR on the interval -3.75000E-01 to 3.75000E-01
C with weighted error 6.35E-32
C log weighted error 31.20
C significant figures required 30.93
C decimal places required 32.01
C
C***REFERENCES (NONE)
C***ROUTINES CALLED D1MACH, DCSEVL, INITDS, XERMSG
C***REVISION HISTORY (YYMMDD)
C 770601 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***END PROLOGUE DLNREL