Looking for documentation on Control.Parallel.Strategies

16 Feb 2007

      Is there anything that documents this further than the Haddock documentation 
available from Haskell.org or the GHC pages?  I've gotten some basic 
parallelism to work using parMap and using >|| and >|, but I had a fold and a 
map that I could logically compute at the same time.  

I found this example for quicksort using GPH:

import Strategies

main = print (quicksort ([999,998..0]::[Int]))

quicksort :: (Ord a, NFData a) => [a] -> [a]
quicksort [] = []
quicksort [x] = [x]
quicksort (x:xs) = (lo ++ (x:hi)) `using` strategy
	where
	lo = quicksort [ y | y <- xs, y < x]
	hi = quicksort [ y | y <- xs, y >= x]
	strategy result = rnf lo `par`
			rnf hi `par`
		  	rnf result

Is the syntax the same for GHC using Control.Parallel.Strategies?  If so, does 
the following execute the two computations from the where clause in parallel?

import Control.Parallel
import Control.Parallel.Strategies

stats bigList summation mean = (stddev, proportions) `using` strategy
	where 
	stddev = sqrt (fold ((+) . (^2) . (-mean)) 0 bigList)
	proportions = map (/summation) bigList
	strategy result = rnf stddev >|| 
			rnf proportions >|| 
			rnf result

Thanks!
--Jeff

Jefferson Heard

Bjorn Bringert

Jefferson Heard

Pepe Iborra

Cale Gibbard

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