DBSI0E(3)

SYNOPSIS
DOUBLE PRECISION FUNCTION DBSI0E (X)

NAME
dbsi0e - Compute the exponentially scaled modified (hyperbolic) Bessel function of the first kind of order zero.

LIBRARY
SLATEC (FNLIB)

CATEGORY
C10B1

TYPE
DOUBLE PRECISION (BESI0E-S, DBSI0E-D)

KEYWORDS
EXPONENTIALLY SCALED, FIRST KIND, FNLIB, HYPERBOLIC BESSEL FUNCTION, MODIFIED BESSEL FUNCTION, ORDER ZERO, SPECIAL FUNCTIONS

AUTHOR
Fullerton, W., (LANL)

DESCRIPTION
DBSI0E(X) calculates the double precision exponentially scaled modified (hyperbolic) Bessel function of the first kind of order zero for double precision argument X. The result is the Bessel function I0(X) multiplied by EXP(-ABS(X)). Series for BI0 on the interval 0. to 9.00000E+00 with weighted error 9.51E-34 log weighted error 33.02 significant figures required 33.31 decimal places required 33.65 Series for AI0 on the interval 1.25000E-01 to 3.33333E-01 with weighted error 2.74E-32 log weighted error 31.56 significant figures required 30.15 decimal places required 32.39 Series for AI02 on the interval 0. to 1.25000E-01 with weighted error 1.97E-32 log weighted error 31.71 significant figures required 30.15 decimal places required 32.63

REFERENCES
(NONE)

ROUTINES CALLED
D1MACH, DCSEVL, INITDS

REVISION HISTORY (YYMMDD)
770701 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)