s18dcf

Purpose

Synopsis

[cy,nz,ifail] = s18dcf(fnu,z,n<,scale,ifail>)

Description

 
 This subroutine evaluates a sequence of values for the modified 
 Bessel function K    (z), where z is complex, -(pi) < arg z <= 
                  (nu)                                         
 (pi), and (nu) is the real, non-negative order. The N-member 
 sequence is generated for orders (nu), (nu)+1,...,(nu)+N-1. 
                                                   z
 Optionally, the sequence is scaled by the factor e .
 
 Note: although the routine may not be called with (nu) less than 
 zero, for negative orders the formula K     (z)=K    (z) may be 
                                        -(nu)     (nu)          
 used.
 
 For very large |z| or ((nu)+N-1), argument reduction will cause 
 total loss of accuracy, and so no computation is performed. For 
 slightly smaller |z| or ((nu)+N-1), the computation is performed 
 but results are accurate to less than half of machine precision. 
 If |z| is very small, near the machine underflow threshold, or 
 ((nu)+N-1) is too large, there is a risk of overflow and so no 
 computation is performed. In all the above cases, a warning is 
 given by the routine.
 

Parameters

s18dcf

Required Input Arguments:

fnu                                   real
z                                     complex
n                                     integer

Optional Input Arguments:                       <Default>

scale (1)                             string   'u'
ifail                                 integer  -1

Output Arguments:

cy (n)                                complex
nz                                    integer
ifail                                 integer