Function j0 

pub unsafe extern "C" fn j0(x: f64) -> f64

Calculate the value of the Bessel function of the first kind of order 0 for the input argument , x.

Nvidia docs

Returns

Returns the value of the Bessel function of the first kind of order 0.

• __nv_j0( ) returns +0.
• __nv_j0(NaN) returns NaN. For accuracy information for this function see the CUDA C Programming Guide, Appendix D.1, Table 7.