plong 0 = Var 0 plong n | even n = Or (Var n) (plong (n-1)) | otherwise = And (Var n) (plong (n-1))
main = do print ((length ∘ vars) (plong 10000000)) real 0m3.290s user 0m3.152s sys 0m0.020s main = do print ((length ∘ vars_) (plong 10000000)) real 0m3.732s user 0m3.680s sys 0m0.024s -- vrsn=varsBromage main = do print ((length ∘ vrsn) (plong 10000000)) real 0m4.164s user 0m4.128s sys 0m0.008s ghc -fglasgow-exts -O2 ghc 6.8.2 @Andrew: It is astonishing to see that your version actually performs the worst (at least on my machine). By looking at your code I had also thought that yours would be the fastest in terms of runtime performance, it was also exactly what I tried but failed to get to here on my own. Maybe future ghc versions will change this in favour of your version. I would like to have someone test it on another machine though: fetch: svn co https://okitsune.svn.sourceforge.net/svnroot/okitsune . build: ghc -fglasgow-exts -O2 Common.hs Propositions.hs Test.hs testS: time ./a.out sert testH: time ./a.out hutton testB: time ./a.out bromage Best regards, Cetin Sert. On 21/02/2008, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > G'day all. > > > Quoting Cetin Sert <[EMAIL PROTECTED]>: > > > -- proposition > > data Prp a = Var a > > | Not (Prp a) > > | Or (Prp a) (Prp a) > > | And (Prp a) (Prp a) > > | Imp (Prp a) (Prp a) > > | Xor (Prp a) (Prp a) > > | Eqv (Prp a) (Prp a) > > | Cns Bool > > deriving (Show, Eq) > > > This is probably the fastest: > > vars :: Prp a -> [a] > vars p = vars' p [] > where > vars' (Var a) = (a:) > > vars' (Not p) = vars' p > > vars' (Or l r) = vars' l . vars' r > {- etc -} > vars' (Cns _) = id > > Cheers, > Andrew Bromage > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >
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