Please note : This help page is not for the latest version of Enterprise Architect. The latest help can be found here.

Prev Next


Modified Bessel function, third kind, integer order.


double x, y, kn();
int n;
y = kn(n, x);


Returns the modified Bessel function of the third kind, of order n of the argument.

The range is partitioned into the two intervals [0,9.55] and (9.55, infinity). An ascending power series is used in the low range, and an asymptotic expansion in the high range.

                      Relative error:
arithmetic   domain     # trials      peak         rms
    DEC       0,30         3000       1.3e-9      5.8e-11
    IEEE      0,30        90000       1.8e-8      3.0e-10

Error is high only near the crossover point x = 9.55 between the two expansions used.