Please take a look at Simon Marlow's free book, *Parallel and Concurrent
Programming in Haskell* (http://chimera.labs.oreilly.com/books/1230000000929).
It will teach you a lot about... the things in the title.
On Thu, Jul 6, 2017 at 10:21 AM Claude Heiland-Allen
Hi Dennis,
On 06/07/17 17:53, Dennis Raddle wrote:
I have a program which does backtracking search in a recursive function. I followed the chapter in "Real World Haskell" to parallelize it. [snip] There's no effect from the R.W.H. ideas. Can I get some suggestions as to why?
You can get timing and other useful diagnostics by compiling with -rtsopts and running with +RTS -s, no need to measure CPU time in your own program.
force :: [a] -> () force xs = go xs `pseq` () where go (_:xs) = go xs go [] = 1
This force doesn't do enough, it just walks the spine. Try this, which forces the elements as well as the shape:
force :: [a] -> () force xs = go xs `pseq` () where go (x:xs) = x `pseq` go xs go [] = 1
Thanks,
Claude -- https://mathr.co.uk _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.