Displaying 1 result from an estimated 1 matches for "exparg_bess".
2002 Oct 17
1
underflow handling in besselK (PR#2179)
The besselK() function knows about overflows/underflows internally;
there is a constant xmax_BESS_K in src/nmath/bessel.h (and referred to
only in bessel_k.c), equal to 705.342, which is checked if expon.scaled is
FALSE. (The equivalent number for bessel_i.c is 709, defined as
exparg_BESS in bessel.h.) However, besselK(x) silently returns +Inf if
x>705.342. This behavior is reasonable for besselI (where the problem is
an overflow), but seems wrong for besselK (since the problem here is an
*underflow*). The answer may be as simple as returning 0 rather than +Inf
in this case....