Welcome to the Leonids Shower Challenge
Watch out, winter is coming! (On the northern hemisphere at least) Although winter has some good sides, all the cold and what not is only good to push your crunchers to the maximum. PrimeGrid is therefore more than happy to oblige and offer a 3 day challenge on Sophie Germain Prime Search (LLR), coinciding with the Leonids Meteor Shower. Be careful with pushing your machines though, wouldn't want to turn it into a meteor!
Sophie Germain was born on April 1, 1776, in Paris, France. She was an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki)
Because of the gender prejudices of the time, her early work was submitted under the pseudonym of M. LeBlanc. Later work was finally submitted under her own name and on 8 January 1816, she became the first woman to win a prize from the Paris Academy of Sciences. While some consider her work lacking in rigor, almost all agree that it was from the lack of a formal education that was denied to her based on her gender.
The modern view generally acknowledges that although Sophie had great talent as a mathematician, her haphazard education had left her without the strong base she needed to truly excel. Louis Bucciarelli and Nancy Dworsky, Germain's biographers, summarize as follows: “All the evidence argues that Sophie Germain had a mathematical brilliance that never reached fruition due to a lack of rigorous training available only to men."(Wiki)
What better way to pay tribute to Sophie Germain than to find a prime with her namesake. Finding a World Record Sophie Germain prime would be incredible and even more amazing if it was found during the Challenge. :) Hey, it's possible. NOTE: A twin prime is also possible in this search because of the quad sieve.
While the Sophie Gemain prime remains elusive, a byproduct of the search are single primes and a fair amount of primes is expected.
To participate in the Challenge, please select only the Sophie Germain Prime Search (LLR) project in your PrimeGrid preferences section. The challenge will begin 14 november 2015 18:00 UTC and end 17 november 2015 18:00 UTC. Application builds are available for Linux 32 and 64 bit, Windows 32 and 64 bit and MacIntel. Intel CPUs with AVX capabilities (Sandy Bridge, Ivy Bridge) will have a very large advantage, and Intel CPUs with FMA3 (Haswell) will be the fastest.
ATTENTION: The primality program LLR is CPU intensive; so, it is vital to have a stable system with good cooling. It does not tolerate "even the slightest of errors." Please see this post for more details on how you can "stress test" your computer. WU's will take ~10 minutes on fast/newer computers and 30+ minutes on slower/older computers. If your computer is highly overclocked, please consider "stress testing" it. Sieving is an excellent alternative for computers that are not able to LLR. :)
Please, please, please make sure your machines are up to the task.
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 14 november 2015 18:00 UTC and received BEFORE 17 november 2015 18:00 UTC will be considered for credit. We will be using the same scoring method as we currently use for BOINC credits.
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
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; 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 Sophie Germain Prime Search
A prime number p is called a Sophie Germain prime if 2p + 1 is also prime. For example, 5 is a Sophie Germain prime because it is prime and 2 × 5 + 1 = 11, is also prime. These numbers are named after Marie-Sophie Germain, an extraordinary "French mathematician who made important contributions to the fields of differential geometry and number theory and to the study of Fermat's Last Theorem." (Wiki)
We'll be searching the form k*2^n-1. If it is prime, then we'll check k*2^n+1, k*2^(n-1)-1, & k*2^(n+1)-1. We are able to do this because a quad sieve was performed for this search. This sieve ensured that k*2^n-1, k*2^n+1, k*2^(n-1)-1, & k*2^(n+1)-1 did not have any small prime divisors. The opportunity to find SG's and Twins in the same sieve file is appealing. However, we "expect" to find a Sophie Germain prime first.
The average time currently spent on testing a SGS Prime across PrimeGrid is 31 minutes. An I2500 with AVX takes about 15 minutes.
For more information about Sophie Germain primes, please visit these links:
For more infomation about Marie-Sophie Germain, please visit these links:
What is LLR?
The Lucas-Lehmer-Riesel (LLR) test is a primality test for numbers of the form N = k*2^n − 1, with 2^n > k. Also, LLR is a program developed by Jean Penne that can run the LLR-tests. It includes the Proth test to perform +1 tests and PRP to test non base 2 numbers. See also:
(Edouard Lucas: 1842-1891, Derrick H. Lehmer: 1905-1991, Hans Riesel: 1929-2014).
PrimeGrid Challenge Overall standings --- Last update: From Pi to Paddy (2016)