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Old 2006-11-25, 05:55   #7
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Jun 2003

5·317 Posts

Originally Posted by rogue View Post
d/l my MultiSieve program. You can build a list of primes into an ABC file (which MultiSieve supports), then start sieving at 2.
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.

I have attached the abc file, try analyzing it for speed ups. Attached file is sieved upto 150 Million n=5 million. If your program finds factors under 150M, please let me know, so I can debug my program.

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