GHC doesn't remove intermediate lists down both branches of a zip, so yes, you'll get intermediate lists. Why not use array indexing, as per your second version (only in Haskell)? Simon | -----Original Message----- | From: Hal Daume III [mailto:hdaume@ISI.EDU] | Sent: 16 May 2002 00:55 | To: GHC Users Mailing List | Subject: efficiency of UArray | | | can we expect a function like: | | sum [x*y | (x,y) <- zip (elems v) (elems u)] | | to be as efficient as, say: | | sum = 0 | for i=1, n | sum = sum + v[i] * u[i] | | ? | | Basically, will any intermediate lists be created here? | | -- | Hal Daume III | | "Computer science is no more about computers | hdaume@isi.edu | than astronomy is about telescopes." -Dijkstra | www.isi.edu/~hdaume | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users@haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-| haskell-users |