Function sinpif_eval 

pub(crate) fn sinpif_eval(y: f64) -> f64

Poly for sin(pi*y) on [-0.25; 0.25]. Generated by Sollya:

d = [0,0.25];
f_sin = sin(y*pi)/y;
Q = fpminimax(f_sin, [|0, 2, 4, 6, 8, 10|], [|D...|], d, relative, floating);

See ./notes/sinpif_0p25.sollya