Welcome to the Diwali/Deepavali Challenge
The sixth Challenge of the 2017 Challenge series is a 5 day challenge to celebrate Diwali/Deepavali. The challenge is being offered on the The Riesel Problem (LLR) application.
Diwali or Deepavali is the Hindu festival of lights celebrated every year in autumn in the northern hemisphere. One of the most popular festivals of Hinduism, it spiritually signifies the victory of light over darkness, good over evil, knowledge over ignorance, and hope over despair. Its celebration includes millions of lights shining on housetops, outside doors and windows, around temples and other buildings in the communities and countries where it is observed. The festival preparations and rituals typically extend over a five-day period, but the main festival night of Diwali coincides with the darkest, new moon night of the Hindu Lunisolar month Kartika in Bikram Sambat calendar. In the Gregorian calendar, Diwali night falls between mid-October and mid-November.
Before Diwali night, people clean, renovate, and decorate their homes and offices. On Diwali night, people dress up in new clothes or their best outfit, light up diyas (lamps and candles) inside and outside their home, participate in family puja (prayers) typically to Lakshmi – the goddess of fertility and prosperity. After puja, fireworks follow, then a family feast including mithai (sweets), and an exchange of gifts between family members and close friends. Deepavali also marks a major shopping period in nations where it is celebrated.
On the same night that Hindus celebrate Diwali, Jains celebrate a festival also called Diwali to mark the attainment of moksha by Mahavira, Sikhs celebrate Bandi Chhor Divas to mark the release of Guru Hargobind from a Mughal Empire prison, and Newar Buddhists, unlike the majority of Buddhists, celebrate Diwali by worshipping Lakshmi.
To participate in the Challenge, please select only the The Riesel Problem (LLR) project in your PrimeGrid preferences section. The challenge will begin 18th October 2017 00:00 UTC and end 23rd October 2017 00:00 UTC. Note the non-standard start time.
Any prime we find in this challenge would be the first TRP k we will have eliminated in over 3 years!
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, Haswell, Broadwell, Skylake, Kaby Lake, Coffee Lake) will have a very large advantage, and Intel CPUs with FMA3 (Haswell, Broadwell, Skylake, Kaby Lake, Coffee Lake) 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. Tasks will take ~16 hours on fast/newer computers and 48+ hours 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. :)
Highly overclocked Haswell, Broadwell, Skylake, Kaby Lake or Coffee Lake (i.e., Intel Core i7, i5, and i3 -4xxx or better) computers running the application will see fastest times. Note that TRP is running the latest FMA3 version of LLR which takes full advantage of the features of these newer CPUs. It's faster than the previous LLR app and draws more power and produces more heat. If you have a Haswell, Broadwell, Skylake, Kaby Lake or Coffee Lake CPU, especially if it's overclocked or has overclocked memory, and haven't run the new FMA3 LLR before, we strongly suggest running it before the challenge while you are monitoring the temperatures.
Please, please, please make sure your machines are up to the task.
Multi-threading is also now available, and can speed up tasks, giving you a greater chance of being the Prime finder.
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 tasks issued AFTER 18 October 2017 00:00 UTC and received BEFORE 23rd October 2017 00:00 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 tasks instead of DETACHING, RESETTING, or PAUSING.
ABORTING tasks allows them to be recycled immediately; thus a much faster "clean up" to the end of an LLR Challenge. DETACHING, RESETTING, and PAUSING tasks causes them to remain in limbo until they EXPIRE. Therefore, we must wait until tasks 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 (May 28, 1929 in Stockholm - December 21, 2014) was 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 of 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 8th, 2017, 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.
Last Primes found at PrimeGrid
402539*2^7173024-1 by Walter Darimont on 2 October 2014. Official Announcement.
502573*2^7181987-1 by Denis Iakovlev on 4 October 2014. Official Announcement.
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).