Function f_j1

pub fn f_j1(x: f64) -> f64

Bessel of the first kind of order 1

Note about accuracy:

• Close to zero Bessel have tiny values such that testing against MPFR must be done exactly in the same precision, since any nearest representable number have ULP > 0.5, for example J1(0.000000000000000000000000000000000000023509886) in single precision have 0.7 ULP for any number with extended precision that would be represented in f32 Same applies to J1(4.4501477170144018E-309) in double precision and some others subnormal numbers