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1) Message boards : Aggie The Pew message board (Message 136582)
Posted 9 hours ago by Profile Michael GoetzProject donor
First time I'll be around for a TdP, so I'm hoping for at least a Prime badge, and a mega (aren't we all?) i don't have the hardware to compete for most of the jersies sadly.


Luck is a good substitute for hardware. :)
2) Message boards : Number crunching : International Day of Education Challenge (Message 136575)
Posted 9 hours ago by Profile Michael GoetzProject donor
Please Note ;

I crunch with 12 CPU's per Task : Time per Task is also 3 mins - 6 sec.


Actually you are not.

You're running PPS-Sieve tasks, on the GPU, in a few minutes. Your 321-sieve tasks are taking much longer.

Neither sieve supports multi-threading. The multi-threading controls on the preferences web page only work for LLR tasks. They are ignored by everything else, including the sieves.
3) Message boards : Problems and Help : GPU Rules of Thumb (Message 136551)
Posted 22 hours ago by Profile Michael GoetzProject donor
All things being equal, as the 'n' in the GFN number (i.e., the "16" in GFN-16) goes up by one, the amount of time it takes to run the task doubles.


So is it fair to say if the difference is really outside that range (as in the 500x I observed going from 17 to 18) there're potentially some settings that are off? Or would one interpret this as the machine has maxed out in some way at 17?


I'd say something is very, very wrong, and you should find out what it is. There's really no settings to change.

Do be aware, however, that BOINC is notorious for having terrible time estimates. It's entirely possible that the "500x" you were seeing didn't represent the actual run time.
4) Message boards : Problems and Help : GPU Rules of Thumb (Message 136547)
Posted 22 hours ago by Profile Michael GoetzProject donor
All things being equal, as the 'n' in the GFN number (i.e., the "16" in GFN-16) goes up by one, the amount of time it takes to run the task doubles.

For example, A GFN-18 takes twice as long as a GFN-17. A GFN-19 takes 4 times as long as a GFN-17. And a GFN-22 takes 32 times as long as a GFN-17.

Of course, it's actually a bit more complex than that, but that's a good enough rule of thumb for you to use to figure out roughly how long a certain size GFN should take on your GPU.
5) Message boards : Generalized Fermat Prime Search : GFN prime discoveries II (Message 136539)
Posted 1 day ago by Profile Michael GoetzProject donor
We've found another n=18 (262144) prime!

On 21 Jan 2020 0:49:54, the 1,828,578 digit prime 9450844^262144+1 was found by Eikelenboom using the OCL2 (combined) app.

The double checker of this task was IKI on 21 Jan 2020 2:35:41 using the OCL2 (combined) app.

Congratulations!
6) Message boards : Generalized Fermat Prime Search : GFN-16 MEGA Prime Search starts March, 14, 2019 (Message 136520)
Posted 1 day ago by Profile Michael GoetzProject donor
Is there a maximum possible gap for b values which result in primes...


This one is actually very easy to answer: No, there is not. At least, none that we know of.

Other than actually finding one, there's no proof that any GFN primes will exist for a given n, so it's possible that no GFN-21s of GFN 22s will ever be found, and it's possible that we'll never find another GFN-20.

It's even possible that no more GFN-15s will ever be found -- although I'd say that's unlikely.

7) Message boards : Generalized Fermat Prime Search : GFN-16 MEGA Prime Search starts March, 14, 2019 (Message 136506)
Posted 1 day ago by Profile Michael GoetzProject donor
9k to go hopefully. 🤞


No matter how far we come, the "expected" distance to the prime should always be the same, namely 250k (in b distance), statistically.

Edit: The true b distance may be closer to 206k because Yves's calculator says 4.86 hits in a range from bmin to bmin+1M, and 1M/4.86 = 206k.

/JeppeSN


I'm genuinely not arguing here, but I can't comprehend that concept. How can it always be 250k away? If that were true we would never find any. Does not compute in my head anyway 🙂


You've just flipped a (fair) coin 100 times and it came up tails all 100 times. What the odds of it coming up tails on the 101st flip? It's still 50%.

Same concept.
8) Message boards : Generalized Fermat Prime Search : GFN-22 CPU tasks enabled (Message 136494)
Posted 2 days ago by Profile Michael GoetzProject donor
My original post said that multi-threading is supported via app_info.xml. This is not correct. GFN-22 can only by run single threaded.
9) Message boards : Aggie The Pew message board (Message 136491)
Posted 2 days ago by Profile Michael GoetzProject donor
I need to see if my son wants me to stress test his new Threadripper for 24 hours. :)
10) Message boards : Generalized Fermat Prime Search : GFN-22 CPU tasks enabled (Message 136489)
Posted 2 days ago by Profile Michael GoetzProject donor
I just enabled CPU tasks for GFN-22.

Don't be stupid, please. These are insanely long tasks. If your computer isn't running 24/7, don't even try. It will take a Haswell-class desktop (i.e., FMA3-capable Intel or Zen 2 AMD) over three weeks to run one of these on a single core.

In most cases, having hyperthreading enabled is a really, really bad idea.

It's strongly suggested to use app_info.xml to enable multi-threading.
(Multi-threading isn't supported at this time.)

If any of this doesn't make sense to you, please do both yourself and your potential wingmates a favor and either run the GPU app instead or just run something else.


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