Tue 10/4 - 10/11 PrimeGrid World Space Week Challenge: TRP-LLR (CPUs only)
starts and ends at 12:00 UTC (08:00 EDT, 05:00 PDT)
From the "edit PrimeGrid preferences" webpage:
Recent average CPU time: 31:08:37
This project has a 10% long job credit bonus and a 10% conjecture credit bonus.
Re bonuses: ESP-LLR, PSP-LLR, SoB-LLR, SR5-LLR, TRP-LLR, and the currently inactive TRP-Sieve are
considered conjecture projects. Specifically, the
goal of TRP-LLR is to find out whether or not 509,203 is the smallest
Riesel number. And the means to this end is to look for primes within a certain search space: If a prime of the form of
k*2^
n-1 is found, then
k is
not a Riesel number. There is just a few of numbers smaller than 509,203 left, but I suppose the search space which is based off of these few numbers is pretty big in terms of computational effort. After all, PrimeGrid already awards a little "long job" credit bonus here. And in the comparably unlikely event that a prime is found via TRP-LLR, it will make it to rank 52 of the current Top 5000 Primes list, according to PrimeGrid's
home page.
Like all of the LLR subprojects except SGS-LLR (AFAICS), TRP-LLR makes use of the LLR2 application which splits the work into a big "main task" for the actual testing of a prime candidate, and a small "verification task" as validation of the main task's result.
I checked the
current active search range of TRP on a Haswell CPU, using the current Linux application binary sllr2_1.3.0_linux64_220821, and got FMA3 FFT lengths between 1120K and 1344K. This means 8.75…10.5 MBytes FFT data sizes. Hence, typical older 4-core desktop CPUs don't have enough processor cache to fit all the "hot data", but e.g. a Zen 2 CCX with 16 MBytes level 3 cache does.
Corresponding to the varied computational payload in TRP-LLR's active search space, credit for main tasks currently varies between ≈7,800 and ≈9,300 according to what I am seeing in random computer's results tables.