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Old 2006-11-25, 19:58   #8
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Apr 2003
Between here and the

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Originally Posted by Citrix View Post
Your program is the first thing I tried, but your program is about 10 times slower than my crude program. (A range of 1 million with n= 0 to 5 M, takes 15 sec to sieve on a intel celeron 1.5 ghz, for my program) So I think your program is not well suited for this kind of search. What do you think?

Both the programs use the same algorithm, as much as I know. Since the gap between 2 numbers remaining can be as large as 1500. I think your program, has to compute that in steps of 50 etc..., this is where it slows down. There is no way, my coding skills can be better than yours.
10 times? That almost sounds like an exaggeration. I suppose it is possible though. Remember, MultiSieve supports multiple bases and any n, not just where n is a prime. Since you are using only base 2, there might be base 2 tricks that I'm not using. If you send me your source I can compare our code and see if there are any tricks I can take advantage of. It has been a couple years since I've worked on the code and I have learned a few things since then, but probable not enough to account for such a huge gap. It doesn't help that I don't have any code optimization tools on x86.
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