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Old 2009-06-10, 17:55   #1
Primeinator
 
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"Kyle"
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Default Enlisting the Help of Universities for GIMPS

This fall I will be attending a university having graduated from a community college in May. I have already met the President and he has quite a reputation for being forward thinking and is well liked by both faculty and students. I would like to present a case to him for enlisting some of the CPU resources on campus for aiding GIMPS. Being a university, these resources are plentiful as there are many "idle" computers sitting around on campus. I would not even suggest this except for the fact that I think he would be open to it. However, I would like to present a structured case including the current status of the project and some background information. The background information is rather easy to obtain... as is the majority of the status information. However, I would like to include the overall status of the project and not just the main range of testing. The PrimeNet page only gives information for exponents up to 100M where as I want to make a short and concise table that also includes 100M digit prefactor project and Operation Billion Digits. This information is not as easy to obtain so I have a few questions to ask. Any help in answering them will be greatly appreciated as well as any input or advice on my idea.

1) If Trial Factoring or P-1 finds a factor, is that the end of it and no double check is assigned where as with an LL a double check is always done?

2) Where can I find a page that displays information on exponents 100M to the cutoff for one billion digits around 332M? I could not see a homepage for this project.

3) I know that Operation Billion Digits has a homepage...however I believe that some indicated more exponents had been trial factored than were indicated on the table on said homepage. Where can I get that information?

Thanks! If I think of anything else I will post it.
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Old 2009-06-10, 18:19   #2
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Quote:
Originally Posted by Primeinator View Post
1) If Trial Factoring or P-1 finds a factor, is that the end of it and no double check is assigned where as with an LL a double check is always done?
Correct. Double checks are just a second LL run to verify that the first LL was correct. They aren't necessary if the number can be proven to be composite by the presence of a factor. A factor can be verified very quickly (the server probably verifies all incoming factors), while an LL can only be verified by being run again and checking that the final residue is the same (Prime95 technically only checks the 64 least significant bits of the final residue).

Good luck with your suggestion. Sorry, but I don't know the answers to your other questions.
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Old 2009-06-10, 18:23   #3
Primeinator
 
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Quote:
Correct. Double checks are just a second LL run to verify that the first LL was correct. They aren't necessary if the number can be proven to be composite by the presence of a factor. A factor can be verified very quickly (the server probably verifies all incoming factors), while an LL can only be verified by being run again and checking that the final residue is the same (Prime95 technically only checks the 64 least significant bits of the final residue).

Good luck with your suggestion. Sorry, but I don't know the answers to your other questions.
Thanks! That answers one question and is definitely a start!
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Old 2009-06-10, 18:42   #4
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Quote:
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<snip>
You've got your exponents and digits mixed up. The PrimeNet page shows exponents up to 1G (IIRC), which is about 300 million digits. The billion digit line is at 3.32G.
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Old 2009-06-10, 19:21   #5
Primeinator
 
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I just realized this. How embarrassing. Okay... so I am in the process of getting information for exponents 0 to 1 billion... but I imagine that past 100M or so this PrimeNet table may not have all the information for people that are doing individual work for the 100M digit prefactor project?? (100 M digits starting at 332M roughly)
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Old 2009-06-10, 19:57   #6
Prime95
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Be sure to let them know that it costs money to run this project. A rough estimate is 50 watts per machine.
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Old 2009-06-10, 20:20   #7
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Quote:
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Be sure to let them know that it costs money to run this project. A rough estimate is 50 watts per machine.
If they haven't enabled the power saving options the more power consumption might be less.
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Old 2009-06-10, 21:59   #8
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I'll check. I thought of another question...

Is there a quick way I can find out how many primes are between 332,192,831 and 333,000,000? Thanks!
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Old 2009-06-10, 22:32   #9
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Quote:
Originally Posted by Primeinator View Post
Is there a quick way I can find out how many primes are between 332,192,831 and 333,000,000? Thanks!
PrimeNet reports that from 332 to 333 there are 51080, of which 27982 have been factored already (a 1.825 ratio). Of the remaining 23098: 2644 are out for factoring, 1041 are assigned for LL, and 19411 are available for assignment.

Come join us over here: http://www.mersenneforum.org/showthread.php?t=10693 Using the new LMH mini-how-to, one could get numerous assignments in the range.

Last fiddled with by Uncwilly on 2009-06-10 at 22:32
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Old 2009-06-10, 22:46   #10
Primeinator
 
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I knew how many from 332 to 333M but I wasn't sure if I could find out from an intermittent exponents.
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Old 2009-06-10, 22:55   #11
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Quote:
Originally Posted by Primeinator View Post
I knew how many from 332 to 333M but I wasn't sure if I could find out from an intermittent exponents.
41287 total expos. You could have looked on-line for a prime lister program. Or written a bute force one for this range. I happened to have one on my HDD. That with a quick line count (via excel). Viola!

http://primes.utm.edu/links/
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