Welcome to the Summer Olympics Challenge
To participate in the Challenge, please select the TRP-Sieve project in your PrimeGrid preferences section. The challenge will begin August 2nd 2016, 21:00:00 UTC and end August 5th 2016, 21:00:00 UTC. Application builds are available for Linux , Windows and MacIntel 32 bit and 64 bit. For sieve tasks such as these, we recommend turning hyperthreading on if your CPU supports it.
ATTENTION: Please note the atypical starting and ending times of this challenge, three hours later than nominal.
[b]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.
Scores will be kept for individuals and teams. Only work units issued AFTER August 2nd 2016, 21:00:00 UTC and received BEFORE August 5th 2016, 21:00:00 UTC will be considered for credit.
Since we use BOINC credit for challenge scoring, each task will be worth 109.22 points. A quorum of 2 is NOT needed to award Challenge score - i.e. no double checker. Therefore, each returned result will earn a Challenge score. Please note that if the result is eventually declared invalid, the score will be removed.
At the Conclusion of the Challenge[list]
We would prefer users "moving on" to finish those tasks they have downloaded, if not then please ABORT the WU's instead of DETACHING, RESETTING, or PAUSING.
ABORTING WU's allows them to be recycled immediately; thus a much faster "clean up" to the end of an LLR Challenge. 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. :)
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 October 2014, there remain 50 k's for which no primes have been found. They are as follows:
2293, 9221, 23669, 31859, 38473, 46663, 67117, 74699, 81041, 93839, 97139, 107347, 121889, 129007, 143047, 146561, 161669, 192971, 206039, 206231, 215443, 226153, 234343, 245561, 250027, 273809, 315929, 319511, 324011, 325123, 327671, 336839, 342847, 344759, 362609, 363343, 364903, 365159, 368411, 371893, 384539, 386801, 397027, 409753, 444637, 470173, 474491, 477583, 485557, 494743
For a more detailed history and status of the Riesel problem, please visit Wilfrid Keller's The Riesel Problem: Definition and Status.
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
Best of Luck!!!
My lucky number is 75898524288+1