Jefferson Heard wrote: > Argh, bitten by the scheme bug! Right -- NO tail recursion... So that leaves > me with some rather non-intuitive strategies for achieving execution time > efficiency. Anyone care to point me in the direction of a document on > efficiency in Haskell?
Besides, proper tail recursion in Haskell needs strictness annotations, but the best way is to forget the two words "tail recursive" altogether :) It always helps to do a rough calculation of how much time you have to expect it to run. Processing 1TB with a 1GHz processor and 16=2^4 machine instruction in the inner loop (must be quite short, the loop) takes 2^40 / (2^30 / 16) = 2^14 seconds ~ 4.5 hours Of course, these 4.5 hours are quite sensitive to the 2^4 factor and might well be 3 or 9 hours. Assuming that you ran alex on a String, the reported 36 hours are entirely reasonable, in the sense of alex not being overly slow. Regards, apfelmus _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
