s21bbf

Purpose

Synopsis

[fun_value,ifail] = s21bbf(x,y,z<,ifail>)

Description

 
 This routine calculates an approximation to the integral
 
                            infty
                          1 /            dt
               R (x,y,z)= - |     -----------------
                F         2 /       _______________
                            0     \/(t+x)(t+y)(t+z)
 
 where x, y, z>=0 and at most one is zero.
 
 Within the domain of definition, the function value is itself 
 representable for all representable values of its arguments. 
 However, for values of the arguments near the extremes the above 
 algorithm must be modified so as to avoid causing underflows or 
 overflows in intermediate steps. In extreme regions arguments are
 pre-scaled away from the extremes and compensating scaling of the
 result is done before returning to the calling program.
 

Parameters

s21bbf

Required Input Arguments:

x                                     real
y                                     real
z                                     real

Optional Input Arguments:                       <Default>

ifail                                 integer  -1

Output Arguments:

ifail                                 integer