| Pré. | Proc. |
i1
Modified Bessel function of order one.SYNOPSIS:
double x, y, i1();
y = i1(x);
DESCRIPTION:
Returns the modified Bessel function of order one of the argument.
The function is defined as i1(x) = -i j1(ix).
The range is partitioned into the two intervals [0,8] and (8, infinity). Chebyshev polynomial expansions are employed in each interval.
ACCURACY:
Relative error:
arithmetic domain # trials peak rms
DEC 0, 30 3400 1.2e-16 2.3e-17
IEEE 0, 30 30000 1.9e-15 2.1e-16