s17agf

Purpose

Synopsis

[fun_value,ifail] = s17agf(x<,ifail>)

Description

 
 This routine evaluates an approximation to the Airy function, 
 Ai(x). 
 
 For large negative arguments, it becomes impossible to calculate 
 the phase of the oscillatory function with any precision and so 
                                                       2/3
                                          (     3     )       
 the routine must fail. This occurs if x<-( ----------)   , where 
                                          ( 2(epsilon))          
 (epsilon) is the machine precision.
 
 For large positive arguments, where Ai decays in an essentially 
 exponential manner, there is a danger of underflow so the routine
 must fail.
 

Parameters

s17agf

Required Input Arguments:

x                                     real

Optional Input Arguments:                       <Default>

ifail                                 integer  -1

Output Arguments:

ifail                                 integer