Well, I finally put in place 6.12.1 and read the documentation for Control.Parallel.Strategies. All of my code for the application described below uses Done, demanding, sparking, (>|), and (>||) which are deprecated and which is what I used. Additionally, I need to understand Eval first to change my code.
No point in responding until I determine what this means. Thanks nevertheless, - Marcus Marcus D. Gabriel wrote: > Denis Bueno wrote: >> On Fri, Dec 18, 2009 at 11:31, Marcus D. Gabriel <mar...@gabriel.name> wrote: >>> than parList via parMap. For example, in one experiment, parMap >>> with parList run at 0.81 the time of the serial solution whereas >>> forceParMap with forceParList run at 0.58 the time of the serial >>> solution. This is to say, forceParList completed in 0.72 the >>> time of parList. So, >> I don't know your application, so it's hard to interpret your numbers. >> >> Are you sure those measurements are statistically significant? > > The particular example that I gave was a straightforward > searchDepthFirst(1) algorithm. To parallelise it, I choose the > initial, simple approach to determine the first list of successor > nodes from an initial node and use parMap to apply the serial > algorithm searchDepthFirst to this list and then reduce (concat) > the list. > > With some RTS tuning and using a dedicated dual-core system, I was > able for the problem above to reproduce the numbers that I cite > above consistently to within about plus or minus a factor of 0.01. > > I have played with variations of this class of problem but not > generally compared parList with forceParList across a broader class > of problems. > > I like your question above. It helped me formulate this question: > > Is what I observed above significant or random? I hope it is not > random. > > I guess the deeper question is how does one determine with > confidence that > > parallised serial algorithm + startegy1 works for problem class1 > > and > > parallised serial algorithm + startegy2 works for problem class2 > > > where both are better than the serial case for their respective > class of problems across a given range of operating environments, > e.g., -N2 to -N8 for 2 to 8 cores. > > - Marcus > > (1) "Algorithms, A Functional Programming Approach" by Fethi Rabhi > and Guy Laplame. ISBN 0201-59604-0. -- Marcus D. Gabriel, Ph.D. Saint Louis, FRANCE http://www.marcus.gabriel.name mailto:mar...@gabriel.name Tel: +33.3.89.69.05.06 Portable: +33.6.34.56.07.75 _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
