On Fri, 2008-12-19 at 15:58 +0100, Daniel Kraft wrote: > How does reverse work in constant space? At the moment I can't imagine > it doing so; that's why I tried it, but of course you could be right.
It allocates a new list cell for every cell it finds in the input list. If the input list can be garbage collected then reverse takes constant space because each time it inspects a list cell from the input list that cell can be garbage collected. If the input list is being retained for some other reason then reverse will take linear space. > > You might get some mileage by suggesting to GHC that your Fraction type > > is strict e.g. > > > >> data Fraction = Fraction !Int !Int > > > > which might persuade it to unbox the Ints, giving some space savings. > > I already tried so, but this doesn't change anything to the performance. > I will however try now to use the provided rational type, maybe this > helps. It will not make any difference to the space used by Fraction unless you also unpack them as I mentioned in my other post. Duncan _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
