User talk:WillNess: Difference between revisions

 

You know me from previous discussions on this and other forums: I like maximum efficiency from any given algorithm including this one, and I think that with this tweak we are pretty well there as far as the algorithm goes. However, there are still some problems with your Haskell implementation as posted on the page when I run it on my actual Windows machine. First, it currently doesn't compile as it is missing some changes you intended to make in moving it from the IdeOne listing: missing 'ww' and changes between estval2 back to estval and so on. There is still a time slow down due to garbage collection: with both 64 and 32 bit code, your non-foldl' version spends over half the time garbage collecting on my machine due to the list comprehensions used and even without the garbage collection is still slow - my version can calculate the trillionth number in just over five seconds for 64/32 using Integer instead of Word64 whereas yours takes about three times as long plus the garbage collection. It looks like you should correct the RosettaCode version to the same foldl' version you use on IdeOne. Even with foldl' to prevent the effects of being non-strict, the overhead of using the list comprehensions still makes your version in 64-bit code about twice as slow as my version. My test program on IdeOne is at http://ideone.com/1Np5Ik and runs just a little bit faster than yours in 32-bit code with Integer but quite a bit faster under 64-bit code with Word64. --[[User:GordonBGood|GordonBGood]] ([[User talk:GordonBGood|talk]]) 08:10, 19 August 2016 (UTC)