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请参加者在自己的 项目页 选择 Prime Sierpinski Project (Sieve)，竞赛时间是北京时间11月14日02:00~11月15日02:00
PrimeGrid's Challenge seriescontinues with the Giving Thanks Challenge. Please come join us in acelebration of PrimeGrid’s users. A 24 hour Challenge is being offeredon PrimeGrid's Prime Sierpinski Project/Seventeen or Bust (Sieve) application.
In this season of giving thanks, we wish to thank you, the user, foranother AMAZING year of crunching. Without you, PrimeGrid would notexist. Please see the next post for some of the accomplishments thisyear.
To participate in the Challenge, please select only the Prime Sierpinski Project (Sieve) project in your PrimeGrid preferences section. The challenge will begin 13 November 2009 18:00 UTC and end 14 November 2009 18:00 UTC. Application builds are available for MacIntel, Linux 32 & 64 bit and Windows 32 & 64 bit. Note: 64 bit builds benefit from a 1.7X speed advantage over 32 bit...so 1.7X the credit. :)
Recommendation: The PSP (Sieve) applicationrequires a one time download of a 10MB sieve file. Please considerrunning a few PSP WU's before the Challenge begins so your client willalready have the sieve file. This way, bandwidth can be used to deliverWU's instead of the sieve file. :) Thank you!
Time zone converter:
The World Clock - Time Zone Converter
NOTE: The countdown clock on the front page usesthe host computer time. Therefore, if your computer time is off, sowill the countdown clock. For precise timing, use the UTC Time in thedata section to the left of the countdown clock.
Scoring Information
Scores will be kept for individuals and teams. Only work units issuedAFTER 13 November 2009 18:00 UTC and received BEFORE 14 November 200918:00 UTC will be considered for credit. Since this is a fixed creditproject, we'll be using cobblestones for scoring.
About the Sierpinski Problem
Waclaw Franciszek Sierpinski (14 March 1882 - 21 October 1969), aPolish mathematician, was known for outstanding contributions to settheory, number theory, theory of functions and topology. It is innumber theory where we find the Sierpinski problem.
Basically, the Sierpinski problem is "What is the smallest Sierpinskinumber" and the prime Sierpinski problem is "What is the smallest 'prime' Sierpinski number?"
First we look at Proth numbers (named after the French mathematicianFrançois Proth). A Proth number is a number of the form k*2^n+1 where kis odd, n is a positive integer, and 2^n>k.
A Sierpinski number is an odd k such that the Proth number k*2^n+1 isnot prime for all n. For example, 3 is not a Sierpinski number becausen=2 produces a prime number (3*2^2+1=13). In 1962, John Selfridgeproved that 78,557 is a Sierpinski number...meaning he showed that forall n, 78557*2^n+1 was not prime.
Most number theorists believe that 78,557 is the smallest Sierpinskinumber, but it hasn't yet been proven. In order to prove it, it has tobe shown that every single k less than 78,557 is not a Sierpinskinumber, and to do that, some n must be found that makes k*2^n+1 prime.
The smallest proven 'prime' Sierpinski number is 271,129. In order to prove it, it has to be shown that every single 'prime' k less than 271,129 is not a Sierpinski number, and to do that, some n must be found that makes k*2^n+1 prime.
Seventeen or Bust is working on the Sierpinski problem and the Prime Sierpinski Project is working on the 'prime' Sierpinski problem. The following k's remain for each project:
Sierpinski problem 'prime' Sierpinski problem
10223 10223*
21181 22699*
22699 67607*
24737 79309
55459 79817
67607 90527
152267
156511
168451
222113
225931
237019
* being tested by Seventeen or BustFortunately, the twoprojects combined their sieving efforts into a single file. Therefore,PrimeGrid's PSP sieve supports both projects.
What is sieving?
Sieving is the first step to prime finding. In general, a sieveseparates wanted/desired elements from unwanted material using a toolsuch as a mesh, net or other filtration or distillation methods. Theword "sift" derives from this term. (Wikipedia - Sieve)
In PrimeGrid's case, the desired elements ultimately are prime numbersand the unwanted material are composite numbers. Our tool of choice forPSP sieve is Geoff Reynolds' sr2sieve program. It eliminates possiblecandidates by removing numbers that have small factors. As this processis much faster than primality testing, it is good to thoroughly sieve adata set before primality testing.
Sieving removes many candidates at the beginning. However, the deeperthe sieve goes, the slower the rate of removal, till eventually sievingremoves candidates at the same rate as primality testing. This issometimes referred to as "optimal depth". Primality testing isrecommended at this point.
There are many factors that determine how much time and how deep tosieve. After sieving, all the remaining candidates must be primalitytested to determine their "prime" status.
Additional Information
For more information about PSP sieve, please see these resources:
For more information about Sierpinski, Sierpinski number, and the Sierpinsk problem, please see these resources:
32 bit OS with 64 bit CPU
This is for those who are "driving with the hand brake active" (runninga 32 bit OS on a 64 bit machine) ;) Wubi is a very nice tool thatinstalls Ubuntu as a dual boot to your 64 bit machine. It's as simpleas adding a program to Windows. You can even uninstall it like youwould any other program. :)
Wubi - Ubuntu Installer
After getting 64 bit OS running on your machine, here's a link to ALL BOINC clients (including Linux x64): http://boinc.berkeley.edu/download_all.php If you are new to Linux and need help getting set up, let us know.
It really is simple. :)
Ubuntu has a power save feature that throttles the CPU frequency downto save power. It does not treat BOINC as an active program so willthrottle down thus causing under-performance. For those downloading thelatest Ubuntu 8.10, please follow these directions to make sure thefrequency is not throttled down while BOINC is running:
1. In Ubuntu, right click the top menu bar
2. Select add to panel
3. Select "CPU Frequency Scaling Monitor"
4. Click add
This will add a processor icon to the top menu. Click on the icon andset to "Performance". This also allows you to see the CPU frequency.
转贴出处在这里
[ 本帖最后由 ledled 于 2009-11-14 00:50 编辑 ] |
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发表于 2009-11-13 10:32:54
发表于 2009-11-13 13:23:50
