Peter Hercek wrote:
Daniel Fischer wrote:
What perpetually puzzles me is that in C long long int has very good performance, *much* faster than gmp, in Haskell, on my computer, Int64 is hardly faster than Integer.
I tried the example with Int64 and Integer. The integer version was actually quicker ... which is the reason I decided to post the results.
C++ version times: 1.125; 1.109; 1.125 Int32 cpu times: 3.203; 3.172; 3.172 Int64 cpu times: 11.734; 11.797; 11.844 Integer cpu times: 9.609; 9.609; 9.500
Interesting that Int64 is *slower* than Integer.
I can believe that. Integer is actually optimised for small values: there's a specialised representation for values that fit in a single word that avoids calling out to the GMP library. As Stefan pointed out, there's a lot of room to improve the performance of Int64, it's just never been a high priority. Cheers, Simon