s18aef

s18aef © Numerical Algorithms Group, 2002.

Purpose

S18AEF Modified Bessel function I (x) 0

Synopsis

[fun_value,ifail] = s18aef(x<,ifail>)

Description

 
 This routine evaluates an approximation to the modified Bessel 
 Function of the first kind I (x).
                             0   
 
 Note: I (-x)=I (x), so the approximation need only consider x>=0.
        0      0                                                 
 
 For large x, the routine must fail because of the danger of 
                          x
 overflow in calculating e .

Parameters

s18aef

Required Input Arguments:

x                                     real

Optional Input Arguments:                       <Default>

ifail                                 integer  -1

Output Arguments:

ifail                                 integer