Hello Tim, Tuesday, November 6, 2007, 3:13:05 AM, you wrote:
Is it possible to use the forkIO primitive to cause pure computations to be evaluated in parallel threads?
It seems to me that laziness would always prevent any evaluation until the result was used in a consuming thread (and hence would occur serially, in that thread).
yes, that's true. but we can force evaluation of array elements: task (i,j) = do putArray arr (i,j) (i*j) return $! getArray arr (i,j) in the Andrew's case, array in unboxed, so putArray will evaluate its argument without additional return$! on the other side, he can use boxed immutable array and use tasks exactly to enforce evaluation of lazy boxes: let arr = array (0,0) (10,10) [i*j | i<-0..10, j<-0..10] let task (i,j) = return $! elemArray arr (i,j) -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com