Function rsqrt

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

Calculate the reciprocal of the nonnegative square root of , x.

Nvidia docs

Returns

Returns .

• __nv_rsqrt( ) returns +0.
• __nv_rsqrt( ) returns .
• __nv_rsqrt(x) returns NaN if x is less than 0. For accuracy information for this function see the CUDA C Programming Guide, Appendix D.1, Table 7.