subf32array_fill(a, start, end, f)
subf64array_fill(a, start, end, f)
Set the elements of the f32/f64array a, beginning with index start (inclusive) and ending
with index end (exclusive) to the floating-point number f.
Return void.
let a = #f64[1., 2., 3., 4., 5.]
subf64array_fill(a, 2, 4, 100.32)
a
// #[1., 2., 100.32, 100.32, 5.]