KWSN Orbiting Fortress

[John Galt 007]

Welcome to the World Maths Day Challenge

World Maths Day - a day to promote numeracy through games and competition. It has been created for students aged 4 – 18 years with the addition for the first time this year of an adult category, ages 19 to 119. Only students in the 4 to 18 age categories are eligible for prizes. Adults just get to join in the fun! Compete against others around the world in live games of mental arithmetic.

This year's goal is 1 billion correct answers...a very ambitious goal considering lasts year total was just under 480 million correct.

Come join the fun and register...there's no charge. Participate and compare your scores to others. NOTE: Actual start time of World Maths Day is 28 Feb 11:00 UTC and will last for 48 hours til 2 Mar 11:00 UTC.

In honor of World Maths Day, PrimeGrid is offering a 24 hour Challenge on The Riesel Problem (Sieve).

To participate in the Challenge, please select only the TRP (Sieve) project in your PrimeGrid preferences section. The Challenge will begin 1 March 2011 18:00 UTC and end 2 March 2011 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.

NOTE: In your PrimeGrid preferences section, set "Send work from any subproject if selected projects have no work" to no to guarantee that no other work will be sent.

Recommendation: The TRP (Sieve) application requires a one time download of a 32.4MB sieve file. Please consider running a few TRP (Sieve) WU's before the Challenge begins so your client will already have the sieve file. This way, bandwidth can be used to deliver WU'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 uses the host computer time. Therefore, if your computer time is off, so will the countdown clock. For precise timing, use the UTC Time in the data section to the left of the countdown clock.

Scoring Information

Scores will be kept for individuals and teams. Only work units issued AFTER 1 March 2011 18:00 UTC and received BEFORE 2 March 2011 18:00 UTC will be considered for credit. Since this is a fixed credit project, we'll be using cobblestones for scoring.

About The Riesel Problem

Hans Ivar Riesel (born 1929 in Stockholm) is a Swedish mathematician. In 1956, he showed that there are an infinite number of positive odd integer k's such that k*2^n-1 is composite (not prime) for every integer n>=1. These numbers are now called Riesel numbers. He further showed that k=509203 was such one.

It is conjectured that 509203 is the smallest Riesel number. The Riesel problem consists in determining that 509203 is the smallest Riesel number. To show that it is the smallest, a prime of the form k*2^n-1 must be found for each of the positive integer k's less than 509203. As of December 2010, there remains 62 k's for which no primes have been found. They are as follows:

2293, 9221, 23669, 31859, 38473, 40597, 46663, 65531, 67117, 74699, 81041, 93839, 97139, 107347, 121889, 123547, 129007, 141941, 143047, 146561, 161669, 162941, 192971, 206039, 206231, 215443, 226153, 234343, 245561, 250027, 252191, 273809, 304207, 315929, 319511, 324011, 325123, 327671, 336839, 342847, 344759, 353159, 362609, 363343, 364903, 365159, 368411, 371893, 384539, 386801, 397027, 398023, 402539, 409753, 415267, 444637, 470173, 474491, 477583, 485557, 494743, 502573

For a more detailed history and status of the Riesel problem, please visit Wilfrid Keller's The Riesel Problem: Definition and Status.

Additional Information


* Riesel Number (Wolfram MathWorld)
* Riesel Number (Wiki)
* Riesel Number (The Prime Glossary)


The Riesel problem is to k*2^n-1 as the Sierpinski problem is to k*2^n+1. There is no equivalent to the 'prime' Sierpinski problem since k=509203, the conjectured smallest Riesel number, is prime.

What is sieving?

Sieving is the first step to prime finding. In general, a sieve separates wanted/desired elements from unwanted material using a tool such as a mesh, net or other filtration or distillation methods. The word "sift" derives from this term. (Wikipedia - Sieve)

In PrimeGrid's case, the desired elements ultimately are prime numbers and the unwanted material are composite numbers. Our tool of choice for PSP/SoB sieve is Geoff Reynolds' sr2sieve program. It eliminates possible candidates by removing numbers that have small factors. As this process is much faster than primality testing, it is good to thoroughly sieve a data set before primality testing.

Sieving removes many candidates at the beginning. However, the deeper the sieve goes, the slower the rate of removal, till eventually sieving removes candidates at the same rate as primality testing. This is sometimes referred to as "optimal depth". Primality testing is recommended at this point.

There are many factors that determine how much time and how deep to sieve. After sieving, all the remaining candidates must be primality tested to determine their "prime" status.

32 bit OS with 64 bit CPU

This is for those who are "driving with the hand brake active" (running a 32 bit OS on a 64 bit machine) Wubi is a very nice tool that installs Ubuntu as a dual boot to your 64 bit machine. It's as simple as adding a program to Windows. You can even uninstall it like you would 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. With that said, check what installations WUBI will NOT work on: Unsupported set-ups

Ubuntu has a power save feature that throttles the CPU frequency down to save power. It does not treat BOINC as an active program so will throttle down thus causing under-performance. For those downloading the latest Ubuntu 10.04 (http://www.ubuntu.com/), please follow these directions to make sure the frequency 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 and set to "Performance". This also allows you to see the CPU frequency.
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( • )Y( • )

[Blurf]

Since it's a quick challenge, I've already dropped my core-5 in
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[Idan]

I guess I can donate 24 hours for good old PG...

I'm in as well!
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Anyone for Crunch?

[williamd007]

2 I7's and a 2 dualcores in from me and since its just a cpu challenge I can still run primegrid cudas on 5 cards

[John Galt 007]

Starts in @45 minutes....
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( • )Y( • )

[Yankton]

And we're off and running!
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Some days are worse than others.

[Clark]

4 cores checking in for duty.

I'm "driving with the handbrake on" as it were.

What's the advantage for BOINC of switching to a 64-bit OS?
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Badges:

[John Galt 007]

[Clark]

Got a 64-bit Win 7 disc....it's just whether I can be bothered to reinstall everything when I've got it running so nicely.
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Badges:

[Gemjunkie]

In with 20 cores, all 64-bit.



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(older, before split CPID)

[stooper101]

I'm a little late and a little under prepared with a glut of Rosetta that was still getting cleared out, but I'm starting PG now.

Onward!
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>stats<

[Gemjunkie]

Team member standings at several points so far.


Last update: 2011 03 01 21:30:06
25 Hal9000x86 The Knights Who Say Ni! 894.96
37 {KWSN}John Galt 007 The Knights Who Say Ni! 596.64


Last update: 2011 03 01 21:45:03
13 {KWSN}John Galt 007 The Knights Who Say Ni! 2386.56
46 Hal9000x86 The Knights Who Say Ni! 894.96
65 Gemjunkie The Knights Who Say Ni! 298.32


Last update: 2011 03 01 22:30:06
22 {KWSN}John Galt 007 The Knights Who Say Ni! 4176.48
49 Gemjunkie The Knights Who Say Ni! 2088.24
85 Hal9000x86 The Knights Who Say Ni! 1193.28


Last update: 2011 03 01 23:00:05
10 {KWSN}John Galt 007 The Knights Who Say Ni! 10441.19
28 Gemjunkie The Knights Who Say Ni! 4773.11
106 Hal9000x86 The Knights Who Say Ni! 1193.28


Last update: 2011 03 01 23:45:05
6 {KWSN}John Galt 007 The Knights Who Say Ni! 15512.62
33 Gemjunkie The Knights Who Say Ni! 4773.11
108 Hal9000x86 The Knights Who Say Ni! 1193.28
155 KWSN - Sir Brian - err sorry - wrong film! The Knights Who Say Ni! 894.96
190 Pooh Bear 27 The Knights Who Say Ni! 298.32


Last update: 2011 03 02 00:00:07
6 {KWSN}John Galt 007 The Knights Who Say Ni! 16109.26
20 Gemjunkie The Knights Who Say Ni! 7756.31
35 KWSN - Sir Brian - err sorry - wrong film! The Knights Who Say Ni! 5071.43
143 Hal9000x86 The Knights Who Say Ni! 1193.28
186 Pooh Bear 27 The Knights Who Say Ni! 596.64



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(older, before split CPID)

[Blurf]

Why me not in there?
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[Gemjunkie]

I just now looked through the list a dozen times, top to bottom & bottom to top, I don't see you, Blurf.
About how many WU's have you finished? Are you sure you selected the right sub-project? Maybe I'm just missing it.

Last update: 2011 03 02 00:45:08
10 {KWSN}John Galt 007 The Knights Who Say Ni! 17899.18
24 Gemjunkie The Knights Who Say Ni! 7756.31
39 KWSN - Sir Brian - err sorry - wrong film! The Knights Who Say Ni! 5071.43
71 Yankton The Knights Who Say Ni! 2983.20
78 Pooh Bear 27 The Knights Who Say Ni! 2983.20
110 Hal9000x86 The Knights Who Say Ni! 2088.24
140 John Mohr The Knights Who Say Ni! 1491.60
191 Williamd007 The Knights Who Say Ni! 894.96
199 Adam Alexander The Knights Who Say Ni! 596.64


Last update: 2011 03 02 01:00:08
10 {KWSN}John Galt 007 The Knights Who Say Ni! 17899.18
25 Gemjunkie The Knights Who Say Ni! 7756.31
43 KWSN - Sir Brian - err sorry - wrong film! The Knights Who Say Ni! 5071.43
78 Pooh Bear 27 The Knights Who Say Ni! 3281.52
83 Yankton The Knights Who Say Ni! 2983.20
95 Hal9000x86 The Knights Who Say Ni! 2386.56
134 Adam Alexander The Knights Who Say Ni! 1789.92
148 John Mohr The Knights Who Say Ni! 1491.60
193 Williamd007 The Knights Who Say Ni! 894.96



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(older, before split CPID)

[Gemjunkie]

I see, Blurf, you completed 24 WU's but these were downloaded before the challenge started. For the challenge, WU's must be downloaded after 18:00UTC on the 1st and completed and reported before 18:00UTC on the 2nd. Otherwise people could crunch all week beforehand and turn in the results on the day of the challenge.





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(older, before split CPID)

[Blurf]

Oh ok, the directions said to start early so the Riesel file would be downloaded.
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[Gemjunkie]

Yes, they suggested running at least one WU beforehand so that the 30MB sieving program would be on your system. I suppose you can abort the rest and start fresh.



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(older, before split CPID)

[Blurf]

Bah too late at this point--not worth it now.
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[Yankton]

You have enough firepower that you have time to contribute quite a bit still. Unless you have a P4 or some such. My P4 (hyper-threaded) started five minutes in. won't complete before the challenge ends.


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Some days are worse than others.

[Gemjunkie]

Last update: 2011 03 02 06:00:29
10 {KWSN}John Galt 007 The Knights Who Say Ni! 35500.04
30 Gemjunkie The Knights Who Say Ni! 17302.54
60 Pooh Bear 27 The Knights Who Say Ni! 10142.87
62 KWSN - Sir Brian - err sorry - wrong film! The Knights Who Say Ni! 9844.55
88 Adam Alexander The Knights Who Say Ni! 7159.67
137 Yankton The Knights Who Say Ni! 4176.48
148 Hal9000x86 The Knights Who Say Ni! 3579.84
187 Williamd007 The Knights Who Say Ni! 2684.88
244 John Mohr The Knights Who Say Ni! 1789.92
288 Idan Shifres The Knights Who Say Ni! 1193.28
377 Sir Stooper The Knights Who Say Ni! 298.32



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(older, before split CPID)