s14baf

Purpose

Synopsis

[p,q,ifail] = s14baf(a,x<,tol,ifail>)

Description

 
 This subroutine evaluates the incomplete gamma functions in the 
 normalised form
 
                                     x       
                              1      / a-1 -t
                  P(a,x)= ---------- |t   e  dt,
                          (Gamma)(a) /       
                                     0       
 
                                   infty       
                            1      /     a-1 -t
                Q(a,x)= ---------- |    t   e  dt,
                        (Gamma)(a) /           
                                   x           
 
 with x>=0 and a>0, to a user-specified accuracy. With this 
 normalisation, P(a,x)+Q(a,x)=1.
 

Parameters

s14baf

Required Input Arguments:

a                                     real
x                                     real

Optional Input Arguments:                       <Default>

tol                                   real     eps
ifail                                 integer  -1

Output Arguments:

p                                     real
q                                     real
ifail                                 integer