Hello again, Another thought.. Could it be that sTree0 is cyclic that accounts for this dramatic slow down? I'm not to sure how DiffArray are implemented, but if it's how I would do it it seems you would end up with a massive chain of indirections. Actually, it's probably not a good idea to have a DiffArray as a top level CAF, cyclic or otherwise? Hmm.. I think that must be it. On Monday 27 Oct 2003 6:21 pm, Adrian Hey wrote:
-- Search Tree data type newtype STree = STree (Array Int (STree,[Match])) -- Initial value for Search Tree sTree0 :: STree sTree0 = STree (array (0,9) [(n,(sTree0,[]))| n <- [0..9]])
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The code is otherwise identical, so any difference in execution time must be caused the difference between reading/writing the respective arrays. I wouldn't expect them to be identical but for DiffArrays to be over 100 times slower seems a bit strange (especially for a relatively small array of 10 elements). That's an O(n^2) difference somewhere (neglecting any constant factors).