Concretely the way I want to use this is to have temporary arrays for cases where I can predict their eltype at evaluation time, but not at the time I’m constructing the object where the temporary array is held. So very crudely, I would do something like this:
mutable struct A
tmp::Vector{UInt8}
# other stuff
end
function evaluate(a::A, x::TX)
T = predict_eltype(TX)
# resize a.tmp if necessary, or replace with larger array
tmp = reinterpret(T, a.tmp)
# ... do some computations in tmp
# return output
end
But then I noticed that the reinterpret sometimes causes a significant slow-down.
I should also acknowledge that the speedup I’m getting by not allocating is not at all clear, sometimes I seem to gain quite a bit, sometimes nothing. Maybe it depends on whether the GC can figure out that I want to reuse my arrays and keeps them around? (Basically that’s the functionality I’m trying to re-implement here…)