On 28/04/14 00:22, John Lato wrote:
Are unboxed vectors faster? My rule of thumb is to use them over Data.Vector whenever possible.
I haven't checked yet, but should it matter? Because my goal is that the vector never be created *at all*, and boxed or not shouldn't make a difference on that!
I would expect it's because you never force the argument. With `enumFromTo` the argument is forced because it needs to be checked for termination, but `enumFromN` is probably building up a big chain of thunks. I guess for this case `enumFromN` has no benefit over `enumFromTo` because the intention is to create a single loop instead of actually allocating the vector, so the warning in the documentation doesn't necessarily apply.
Also haven't checked that yet, but I suspect that instead of something thunk-related, the thing plainly allocates the vector. Just to clarify: `V.enumFromTo` works much better than `V.enumFromN` because in contrast to the latter it doesn't actually try to create the fully sized vector.