sinc function
Implementation
VARP sinc(VARP x) {
final pi = F.scalar(math.pi, dtype: x.dtype);
final pix = pi * x;
final zero = F.scalar(0, dtype: x.dtype);
final one = F.scalar(1, dtype: x.dtype);
final mask = equal(x, zero);
final safePix = where(mask, x: one, y: pix);
return where(mask, x: one, y: sin(pix) / safePix);
}