intdeiini

I = integral of f(x) over (a,infinity), f(x) has not oscillatory factor.

void

intdeiini

(

Real

)

(

size_t lenaw

Real tiny

Real eps

Real* aw

)

Parameters

lenaw size_t: length of aw
tiny Real: minimum value that 1/tiny does not overflow
eps Real: relative error requested
aw Real*: points and weights of the quadrature formula, aw[0...lenaw-1]
lenaw size_t: 8000;
tiny Real: 1.0e-307; function f(x) needs to be analytic over (a,infinity). relative error eps is relative error requested excluding cancellation of significant digits. i.e. eps means : (absolute error) / (integral_a^infinity |f(x)| dx). eps does not mean : (absolute error) / I. error message err >= 0 : normal termination. err < 0 : abnormal termination. i.e. convergent error is detected : 1. f(x) or (d/dx)^n f(x) has discontinuous points or sharp peaks over (a,infinity). you must divide the interval (a,infinity) at this points. 2. relative error of f(x) is greater than eps. 3. f(x) has oscillatory factor and decay of f(x) is very slow as x -> infinity. </pre>

auto aw = new real[8000];
intdeiini(aw.length, tiny, eps, aw.ptr);  // initialization of aw
...
intdei(f, a, aw.ptr, &i, &err);