[Haskell-cafe] Re: FASTER primes

[Will Ness]

Daniel Fischer <daniel.is.fischer <at> web.de> writes:

> 
> 
> Am Donnerstag 07 Januar 2010 11:43:44 schrieb Heinrich Apfelmus:
> > Will Ness wrote:
> > > Heinrich Apfelmus writes:
> 
> The below code is now a well-behaved memory citizen (3MB for the 100 
millionth prime, about the same as the PQ code). It still is considerably 
slower than the PQ code.
> In terms of MUT times as reported by +RTS -sstderr - as well as (MUT+GC) 
times - (measured once for prime No. 5*10^5, 10^6, 2*10^6, 4*10^6, 10^7 to get 
a rough tendency), it seems to scale a wee bit better than any of the other 
tfold versions I created, but a little worse than the PQ versions.
> The relation of MUT times isn't too bad, but the GC times are rather abysmal 
(30-40%).
> 
> ----------------------------------------------------------------------
> 
> data People a = P { vips :: [a], dorks :: [a] }
> 
> celebrate x p = P (x:vips p) (dorks p)
> 
> mergeSP p1@(P a _) p2 = P (a ++ vips mrgd) (dorks mrgd)
>       where
>         mrgd = spMerge (dorks p1) (vips p2) (dorks p2)
>         spMerge l1 [] l3 = P [] (merge l1 l3)
>         spMerge ~l1@(x:xs) l2@(y:ys) l3 = case compare x y of
>                 LT -> celebrate x (spMerge xs l2 l3)
>                 EQ -> celebrate x (spMerge xs ys l3)
>                 GT -> celebrate y (spMerge l1 ys l3)
> 


I forgot to say something *very* important. :) Here it is.


Yippee-hurray!


:)