On Sunday 30 Jan 2005 4:00 pm, Axel Jantsch wrote:
Main> nth 100 fibs 10 (2818 reductions, 3730 cells, 1 garbage collection)
Main> nth 200 fibs 10 (5618 reductions, 7430 cells, 1 garbage collection)
which suggests linear space behaviour.
Hmm, not sure exactly what Hugs is measuring here. I suspect this is a measure of total allocation during program execution rather than maximimum memory in use at any time during execution. So you'd expect to see this kind of thing anyway. As it happens, I think both heap and stack requirement will be proportional to the first arg of nth for the reasons I indicated earlier. But I think the version using zipWith' will execute in constant space (but this doesn't mean constant cell allocation, you'll probably still see <some large number> of cells used). Regards -- Adrian Hey