Welcome to the Winter Solstice Challenge

The Final Challenge of the 2009 Challenge series is upon us. The Winter Solstice Challenge marks the culmination of 9 Challenges this year. And to top things off, this is the deciding Challenge to determine who wins for the year. A 3 day (72 hour) Challenge is being offered on PrimeGrid's AP26 Search application.

There are EXCITING races in both the Teams and Participant categories. The results of this Challenge will determine the overall Champions.

The Winter Solstice...a predictable event in nature that has occurred for billions of years. A way point in the cyclic motion of the Universe. Many of the today's major winter festivals and celebrations can trace their origins back to this event...the longest night of the year (or the shortest day).

We'd like to wish everyone a Happy Holiday...whatever festival or celebration you may observe.

NOTE: The servers are located in the Northern Hemisphere; therefore, we'll observe winter. However, the Southern Hemisphere will be experiencing the Summer Solstice.

To participate in the Challenge, please select only the AP26 Search project in your PrimeGrid preferences section. The challenge will begin 18 December 2009 17:47 UTC and end 21 December 2009 17:47 UTC. Application builds are available for the following:

• Microsoft Windows (98 or later) running on an Intel x86-compatible CPU
  
• Microsoft Windows running on an AMD x86_64 or Intel EM64T CPU
  
• Linux running on an Intel x86-compatible CPU
  
• Linux running on an AMD x86_64 or Intel EM64T CPU
  
• Mac OS 10.3 or later running on Motorola PowerPC
  
• Mac OS 10.4 or later running on Intel
  
• Mac OS 10.5+ running on an Intel 64-bit CPU
  
• Solaris 2.8+ on an AMD x86_64 or Intel EM64T CPU
  
• Cell/BE Linux (Playstation 3)
  
• GPU (32/64 Windows & 64 Linux) - a CUDA23 application has been released. Please see more information here.
  

WU times (These need to be updated. Please post your current WU times in the AP26-runtimes for different apps and architectures thread.) All I did was double the last challenge times.

Elite: 16-20 minutes
Fast: 26-30 minutes
Average: 40 minutes
Slower: 60-80 minutes
Slowest: 120+ minutes

For a list of "notable" AP's found by PrimeGrid, see the AP26 Stats page. For an extensive list of record AP's, please see Jens Kruse Andersen's Primes in Arithmetic Progression Records page.

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 18 December 2009 17:47 UTC and received BEFORE 21 December 2009 17:47 UTC will be considered for credit. Since this is a fixed credit project, we'll be using cobblestones for scoring.

Credit is currently set at 23.61 cobblestones per WU.

About the AP26 Search (Arithmetic Progression of 26 primes)

An arithmetic progression is a sequence of numbers with a common difference between any two successive numbers in the sequence. For instance, the sequence 3, 5, 7, 9, 11, 13, 15, ... is an arithmetic progression with a common difference of 2.

Therefore, an arithmetic progression of primes is a sequence of primes with a common difference between any two successive numbers in the sequence. For example 3, 7, 11 is an arithmetic progression of 3 primes with a common difference of 4.

For an arithmetic progression (AP) of primes, AP-k is k primes of the form p + d*n for some d (the common difference between the primes) and k consecutive values of n. The above AP-3 is 3 + 4*n for n=0,1,2.

n=0; 3 + 4*0 = 3 + 0 = 3
n=1; 3 + 4*1 = 3 + 4 = 7
n=2; 3 + 4*2 = 3 + 8 = 11

Another example is the AP-10 of the form 199 + 210*n for n=0..9. This produces the following sequence: 199, 409, 619, 829, 1039, 1249, 1459, 1669, 1879, 2089.

AP-k is also sometimes notated PAP-k (Primes in Arithmetic Progression).

We are searching for the longest AP, not the largest. The current record is an AP25 discovered 17 May 2008 by Raanan Chermoni & Jaroslaw Wroblewski. PrimeGrid tied the record by finding an AP25 on 8 Apr 2009 (BOINC@Poland, PrimeGrid, AP26). For a complete list of records including longest and largest AP's, please see Jens Kruse Andersen's Primes in Arithmetic Progression Records. Also, a list of the top 20 largest AP's can be found at The Prime Pages: The Top 20

Jaroslaw Wroblewski's AP26 code will be used for the search. Geoff Reynolds adapted the program for use with BOINC and for compiling without GMP. Several others have contributed to improving the code and porting it to other platforms.

Additional information can be found here:

How to search for 26 primes in arithmetic progression? by Jaroslaw Wroblewski
Primes in arithmetic progression - Wikipedia
Prime Arithmetic Progression - Wolfram MathWorld
arithmetic sequence - The Prime Glossary at the Prime Pages

About the Winter Solstice

• Wikipedia
  

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. :)

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 8.10, 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.
____________

For those that are looking to tweak their computers for the final challenge, here is some information on the fastest AP26 computer setup with current apps:

Intel Core(tm) CPU, 64bit Linux distro such as CentOS or Red Hat Enterprise, and multiple Nvidia CUDA video cards.

My example machine, just setup today:
http://www.primegrid.com/show_host_detail.php?hostid=122106

Intel Q6600 @ 2.4 running CentOS 5.4 with 2 gpus: GTS240, GTS250... about 14,000 credits/day


Anyone running multiple GPUS should certainly switch to CentOS/RedHat since the CUDA application runs the fastest, with a small amount of CPU used to feed the GPU. Also, I find that the Nvidia driver installer just "works" without any problems.


The Windows applications for CPU are using the same code and compiler as the Linux versions, but when timed they are slower on the same hardware. The Windows CUDA application is slower than the Linux version due to changes necessary to get the GPU to run with a fully loaded CPU.

I hope this helps anyone looking to optimize their "farm" for AP26!

Bryan

____________

How to Join the Challenge

To participate in the Challenge, please select only the AP26 project in your PrimeGrid preferences section. The challenge will begin 18 December 2009 17:47 UTC and end 21 December 2009 17:47 UTC (on the Winter Solstice). Only work units issued AFTER 18 December 2009 17:47 UTC and received BEFORE 21 December 2009 17:47 UTC will be considered for credit.

Application builds are available for the following:

• Microsoft Windows (98 or later) running on an Intel x86-compatible CPU
  
• Microsoft Windows running on an AMD x86_64 or Intel EM64T CPU
  
• Linux running on an Intel x86-compatible CPU
  
• Linux running on an AMD x86_64 or Intel EM64T CPU
  
• Mac OS 10.3 or later running on Motorola PowerPC
  
• Mac OS 10.4 or later running on Intel
  
• Mac OS 10.5+ running on an Intel 64-bit CPU
  
• Solaris 2.8+ on an AMD x86_64 or Intel EM64T CPU
  
• Cell/BE Linux (Playstation 3)
  
• GPU (32/64 Windows & 64 Linux) - a CUDA23 application has been released. Please see more information here.
  

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 18 December 2009 17:47 UTC and received BEFORE 21 December 2009 17:47 UTC will be considered for credit. Since this is a fixed credit project, we'll be using cobblestones for scoring.

Credit is currently set at 35.41 cobblestones per WU.

Stats will be available on the front page next to the timer within 30 minutes after the start.

What to expect at Challenge start

The server always gets hit hard at the beginning of the Challenge. However, a procedure that we've been using for all the Challenges this year has been very successful so far, and we hope it holds true for the final Challenge. A few hours before the start (18 December 2009 17:47 UTC) "max cache" will be dropped to 16 tasks per core. Additionally, "max to send" will be dropped to 8 tasks per core. Anyone attempting to request more will be met with "max cache" messages.

We'll load at least 500K into the buffer. At the start of the Challenge, these settings will be adjusted as necessary. However, if the past year is any indication, we'll make the first adjustment around 30 minutes post start by raising "max cache" to 32. We'll continue to increase "max cache" when the server can handle it until a full 3 days max cache is possible.

This method allows the greatest opportunity for the most clients to get work. Even if it's just 1 task for the first 10 minutes, at least the client is crunching. Past Challenges have shown that clients have a good chance to reach "max cache" before their first task is complete. We expect the same this time.

Strategies for starting the Challenge

Depending on a variety of factors, different strategies work for different users. Here are just a few to consider:

• large farm, user can be present at start
  -Set Computer is connected to the Internet about every to 0 days
  -Set Maintain enough work for an additional to 0 days
  -Change PrimeGrid preferences to a fast WU project such as PPS LLR
  -At Challenge start, update PrimeGrid preferences and only select AP26 project
  -After all machines have work, increase Maintain enough work for an additional
  
• large farm, user NOT able to be present at start
  -Same settings as above but skip the fast WU project and go directly to ONLY AP26 project.
  -At worse, you'll only be 1 WU late on each core starting the Challenge.
  
• a few computers, user can be present at start
  -Change PrimeGrid preferences and only select AP26 project
  -Set computers to "No New Tasks" for PrimeGrid
  -At Challenge Start, update computers to "Allow New Tasks"
  
• a few computers, user NOT able to be present at start
  -Set Computer is connected to the Internet about every to 0 days
  -Set Maintain enough work for an additional to 0 days
  -Change PrimeGrid preferences and only select AP26 project
  -At worse, you'll only be 1 WU late on each core starting the Challenge.

NOTE: This presumes you have all other BOINC projects suspended.

Best of Luck to everyone!
____________

Is the setting ""max to send" will be dropped to 8 tasks" for each CPU or for the host?
It the latter hosts with more than 8 CPUs and 1 GPU are hampered by this setting.

It'll just mean a 16 core box will have to connect twice to get initial work - not a major problem.
Once you have the initial work, the per-core limit will be the main limiter.
____________

Is the setting ""max to send" will be dropped to 8 tasks" for each CPU or for the host?
It the latter hosts with more than 8 CPUs and 1 GPU are hampered by this setting.

13 hours to go!!!

The witching hour is upon us. 13 hours till the start of the Winter Solstice Challenge. The pre-fires have a nice red glow, and we're expecting them to turn a deep blue once the Challenge begins. Who knows...by the end of the Challenge they may become white hot. :)

Please once again review the "Welcome" post as well as the "How to Join" post so you can be informed and make any last minute adjustments that are necessary.

A few hours before the Challenge, we begin to monitor the Meebo chat room at the bottom of the forum page. If at any time PrimeGrid becomes unresponsive, you can still access the Meebo chat room externally here: http://www.meebo.com/room/primegrid/

Before the start, the Subproject stats on the Server Status page will be disabled as will the 24 hour stats on the bottom of the front page. Also, the Top Primes Finder page will be disabled. This is all done to free up as much resources to allow the server to send and receive work.

What to expect at Challenge start

The server always gets hit hard at the beginning of the Challenge. However, a procedure that we've been using for all the Challenges this year has been very successful so far, and we hope it holds true for the final Challenge. A few hours before the start (18 December 2009 17:47 UTC) "max cache" will be dropped to 16 tasks per core. Additionally, "max to send" will be dropped to 8 tasks per core. Anyone attempting to request more will be met with "max cache" messages.

We'll load at least 500K into the buffer. At the start of the Challenge, these settings will be adjusted as necessary. However, if the past year is any indication, we'll make the first adjustment around 30 minutes post start by raising "max cache" to 32. We'll continue to increase "max cache" when the server can handle it until a full 3 days max cache is possible.

This method allows the greatest opportunity for the most clients to get work. Even if it's just 1 task for the first 10 minutes, at least the client is crunching. Past Challenges have shown that clients have a good chance to reach "max cache" before their first task is complete. We expect the same this time.
____________

The source of the app is open source so no one holds you back to implement an ATI-version of the application. ;)

And we're off! :)
____________

Yes, something looks weird.

First:

137___47________waffleironhead

I thought each WU was 35 credits?

Second:

123___70________Ken_g6 - TeAm Anandtech

But I submitted 4 at once!
____________

27 Larry256 SETI.USA 212.48
28 tiss Ukraine 212.46

How can this be with fixed credits for each WU ?

Stat links are on the homepage, under the timer.

I see how my two questions work. waffleironhead had 2 of the old WUs somehow. Meanwhile, for some reason, two of my WUs are still pending. Huh.
____________

Don't forget to follow new AP's at http://twitter.com/primegrid. We'll also announce any significant (length 24 or greater) ones here in this thread.
____________

I wasn't here for the start, but everything seems pretty smooth right now.

I even started up the the old PIII 1ghz :)
____________

229 WUs crunched and only one AP21 found up to now.
Will buy a new PSU for my Xeon E5405 tomorrow and put it up to help my staggering team a little bit out.

Two AP24's found so far:

22133406276301387+15744033*23#*n for n=0..23
7448460750808573+27806605*23#*n for n=0..23
____________

1000 WUs since start of the challenge for me...

Third AP24 found:

3694862982684983+28285375*23#*n for n=0..23
____________

1000 WUs since start of the challenge for me...

I'm still trying to get a WU on an Intel Atom to finish...

[quote2000 WUs, 3 x AP20's, 1 x AP21
Everything is progressing according to my plans... ;)[/quote]

How can I find out that I've discovered an AP? Everything else I can see on my projects page, but on AP26 search is only number of tasks done and the amount of cobblestones, of course.

Only AP20+ are reported in the stats.
If you only have WUs done + credit you haven't found a AP20+ up to now.
I have 700000+ credits and 29350+ WUs crunched for the AP26-subproject, that is 20-fold of your overall credit - i think you have to crunch some more AP26-WUs to find one AP20+.

No idea what the problem is there, sorry.
A slow-down under windows is normal as it seems but that much terminations...

Fourth AP24 found:

44265615051136733+7821972*23#*n for n=0..23
____________

I think that I have the 3 AP20...

Is that...?

AP26 tasks
Completed tests 1547
Credit 45,386.47
Found of length 20 3




I'm new in the project, so... Must I to do something with that...?

(sorry for my bad english)

Fifth AP24 found:

6450318626856161+30430175*23#*n for n=0..23
____________

Only 13 hours remain!

Now's the time to start preparing for the end of the Challenge. Please remember to upload early and often. The server is going to get hit hard as the Challenge draws to an end. We will start to lower "max cache" to help with this.

Only work units issued AFTER 18 December 2009 17:47 UTC and received BEFORE 21 December 2009 17:47 UTC will be considered for credit.

For those "moving on" at the conclusion of the Challenge, we ask that you abort your WU's after the end. This helps out greatly with the clean up. However, if you have the resources, please consider completing the work in your cache before "moving on".

Good Luck to everyone as we finish these last 13 hours...

At the Conclusion of the Challenge

We kindly ask users "moving on" to ABORT their WU's instead of DETACHING, RESETTING, or PAUSING.

ABORTING WU's allows them to be recycled immediately. DETACHING, RESETTING, and PAUSING WU's causes them to remain in limbo until they EXPIRE. Therefore, we must wait until WU's expire to send them out to be completed.

Please consider either COMPLETING what's in the queue or ABORTING them. Thank you. :)

____________

Sixth AP24 found:

17014421509997489+17580742*23#*n for n=0..23
____________

The results are Final!

The Winter Solstice is here!!! But the night is far from dark. The solstice fires are brighter than ever as the final Challenge of 2009 also happens to be the most active Challenge to date. PrimeGrid's overall (Challenge + regular work) daily record was SMASHED with over 15.9M cobblestones for a 24 hour period. Congratulations to everyone...this is an incredible accomplishment...even in the absence of the AP26.

Over 970K WU's were completed resulting in over 34.4M cobblestones awarded...an astounding amount of work done. 6 new AP24's were found along with the following:

AP19: 8263
AP20: 2209
AP21: 524
AP22: 126
AP23: 25
AP24:

17014421509997489+17580742*23#*n for n=0..23
6450318626856161+30430175*23#*n for n=0..23
44265615051136733+7821972*23#*n for n=0..23
3694862982684983+28285375*23#*n for n=0..23
22133406276301387+15744033*23#*n for n=0..23
7448460750808573+27806605*23#*n for n=0..23

226 teams and 1815 individuals participated in the Challenge.

The Challenge Points stats will be updated soon. Congratulations to SETI.USA as the top team and Mr. Hankey as the top individual. Remember, the top 30 places earn points for this Challenge.

This concludes PrimeGrid's 2009 Challenge Series. Overall final results will be posted soon.

Thank you again to everyone. We appreciate your participation and hope you had fun! We wish you a Happy Holidays and see you next year!

Stats: Participants | Teams

Sponsor a graphics card and count me in... ;)

"ghost"-WUs? huh?
Abort them if you feel guilty.

That was fun. Thanks to all especially those I strove with neck and neck and of course those who made it possible. Next time could I have some wus which generate an interesting result?

Probably I mentioned it before (but that never stops me) the challenge series has proved so successful that I think it'd be neat for future series to award points to more competitors say the first 100 teams and the first 500 participants. It'd make it more fun for more people and hence generate more interest and hence more wus processed..

"... as Tiny Tim observed, God bless Us, Every One!*"

Cheers!

T


*ex Charles Dickens, A Christmas Carol. If you have a different god or no god, I still send my compliments of the season.

That was fun - and the closest of finishes for the last of the points:

What I'm amazed about is that the server kept up and only crashed immediately after the challenge when a lot of result aborts happened :)
____________

that was a heckuva challenge. I've never seen so many folks or teams on a PG challenge.