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SR5 Mega Prime Find!
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Scott Brown Volunteer moderator
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Joined: 17 Oct 05
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On 19 June 2022, 04:26:15 UTC, PrimeGrid’s Sierpinski/Riesel Base 5 Problem project eliminated k=63838 by finding the mega prime:
63838*5^3887851-1
The prime is 2,717,497 digits long and enters Chris Caldwell's “The Largest Known Primes Database” ranked 99th overall. 58 k’s now remain in the Riesel Base 5 problem.
The discovery was made by Scott Lee (freestman) of China using an AMD Ryzen 5 2600X Six-Core Processor with 32GB RAM, running Microsoft Windows 11 Professional x64 Edition. This computer took about 4 hours, 34 minutes to complete the prp test using LLR2. Scott is a member of the team, Chinese Dream.
The prime was verified on 19 June 2022, 22:29 UTC, by an Intel(R) Core(TM) i3-9100F CPU @ 3.60GHz with 16GB RAM, running Linux. This computer took about 11 hours and 57 minutes to complete the primality test using LLR2.
For more details, please see the official announcement. | |
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Neat.
Does this mean there's only 58 WU's left on the project, or what exactly does "58 k's left" denote, in terms of how much work is left to do on the project?
Just in case it helps, I've basically switched my CPU compute over exclusively to the Sierpinski / Riesel Base 5 project for now.
GPU is still on a couple other things.
Anyway, my CPU is a 3700X, and running on all 8 Cores / 16 Threads, it's crunching a WU about every 2 hours. :) Heh! Lots of "1st"(s) in my history...
Here's hoping I bingo some primes! | |
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The ks refer to the numbers for primes of the form k*5^n+/-1 listed here
https://www.primegrid.com/forum_thread.php?id=5087
There are many more WUs (workunits) left, as the vast majority are composites and not primes that would eliminate a k from the list | |
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The ks refer to the numbers for primes of the form k*5^n+/-1 listed here
https://www.primegrid.com/forum_thread.php?id=5087
There are many more WUs (workunits) left, as the vast majority are composites and not primes that would eliminate a k from the list
Yes, check https://www.primegrid.com/forum_thread.php?id=5087.
You can also see the status on https://www.primegrid.com/stats_sr5_llr.php.
Each time we have a number k (but I suppose we do not care about k that are odd or end in a 0), we want to know if any of the numbers:
k*5 - 1; k*5^2 - 1; k*5^3 - 1; k*5^4 - 1; k*5^5 - 1; k*5^6 - 1; ...
are prime. For some special k (Riesel numbers to base 5), the first of which is 346802, we can prove that no prime will ever occur.
For the rest of the k we think there will be primes, but we cannot prove it. In other ways than searching for a prime! As soon as we find a prime, we typically leave that k value and focus on the other remaining k.
The prime found here was about k=63838. We discovered that the sequence:
63838*5 - 1; 63838*5^2 - 1; 63838*5^3 - 1; 63838*5^4 - 1; 63838*5^5 - 1; 63838*5^6 - 1; ...
contains a prime, just like we suspected. It was the 3887851st number on that list that turned out to be prime.
/JeppeSN | |
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My 3 PC's just received 70 SR5 WU's. I noticed all 70 are time outs from other users. Is this normal? I'm curious if these users know something that I don't. They are mine now, so I'm going to crunch them either way. | |
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My 3 PC's just received 70 SR5 WU's. I noticed all 70 are time outs from other users. Is this normal? I'm curious if these users know something that I don't. They are mine now, so I'm going to crunch them either way.
We are probably in the wrong thread.
No, there is no way other users could know "something". Some users do not have good settings, and they get too many tasks. Also, BOINC sometimes does unexpected things, giving you too many tasks. Timeouts and aborts often occur for that reason.
Why do you take 70 work units for 3 PCs? Sounds like too many. Usually, there is no reason to take more tasks than you can start on immediately. But is I said, BOINC's settings can be tricky. When I look at your computers, you have way too many tasks "in progress". I would say you should change settings, and abort some tasks that have not started yet.
/JeppeSN | |
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 mikey
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Joined: 17 Mar 09
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My 3 PC's just received 70 SR5 WU's. I noticed all 70 are time outs from other users. Is this normal? I'm curious if these users know something that I don't. They are mine now, so I'm going to crunch them either way.
Another reason for time outs is drive or pc crashes and you just have to start over and get new tasks | |
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