Sorry, to make it more clear: in the line:

write a (a'!(i-1) + a!(i-2)) only (a'!(i-1) + a!(i-2)) would need to be parallel, as there we typically have a sum/minimum or whatever. The forM_ over each index does not need to be, since we have to fill the array anyway...

* Christian Höner zu Siederdissen [04.05.2010 01:22]:

Hi,

on that topic, consider this (rather trivial) array:

a = array (1,10) [ (i,f i) | i <-[1..10]] where f 1 = 1 f 2 = 1 f i = a!(i-1) + a!(i-2)

(aah, school ;)

Right now, I am abusing vector in ST by doing this:

a <- new a' <- freeze a forM_ [3..10] $ \i -> do write a (a'!(i-1) + a!(i-2))

Let's say I wanted to do something like this in dph (or repa), does that work? We are actually using this for RNA folding algorithms that are at least O(n^3) time. For some of the more advanced stuff, it would be really nice if we could "just" parallelize.

To summarise: I need arrays that allow in-place updates.

Otherwise, most libraries that do heavy stuff (O(n^3) or worse) are using vector right now. On a single core, it performs really great -- even compared to C-code that has been optimized a lot.

Thanks and "Viele Gruesse", Christian