s21bdf

s21bdf © Numerical Algorithms Group, 2002.

Purpose

S21BDF Symmetrised elliptic integral of 3rd kind R (x,y,z,r) J

Synopsis

[fun_value,ifail] = s21bdf(x,y,z,r<,ifail>)

Description

 
 This routine calculates an approximation to the integral
 
                           infty
                         3 /                 dt
        R (x,y,z,(rho))= - |     --------------------------
         J               2 /                _______________
                           0     (t+(rho))\/(t+x)(t+y)(t+z)
 
 where x, y, z>=0, (rho)/=0 and at most one of x, y and z is zero.
 
 If p<0, the result computed is the Cauchy principal value of the 
 integral.
 
 The routine may fail either because it has been called with 
 arguments outside the domain of definition or with arguments so 
 extreme that there is an unavoidable danger of setting underflow 
 or overflow.
 
                    -3/2                                        
 Note: R (x,x,x,x)=x    , so there exists a region of extreme 
        J                                                   
 arguments for which the function value is not representable.

Parameters

s21bdf

Required Input Arguments:

x                                     real
y                                     real
z                                     real
r                                     real

Optional Input Arguments:                       <Default>

ifail                                 integer  -1

Output Arguments:

ifail                                 integer