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drummers-lowrise
1) Message boards : Seventeen or Bust : The SoB Double Check is DONE!!! (Message 133618)
Posted 5 days ago by Profile MyrskylyhtyProject donor
So, still a chance that the DC yields a prime ;)
2) Message boards : Fermat Divisor Search : Fermat Divisor Search (Message 133397)
Posted 13 days ago by Profile MyrskylyhtyProject donor
So, 24 days for 4 %, which translates into 6 days per 1 %.

That's 576 days left, which means we would finish on 28.4.2021.

But I estimate that the challenge + multithread efficiency + new hardware could mean that we finish during next year. Let's see :)
3) Message boards : Fermat Divisor Search : Fermat Divisor Search (Message 133016)
Posted 23 days ago by Profile MyrskylyhtyProject donor
I did a bit of checking into FFT size increases:

k=11:
FFT length 288K: n = 4,713,563
FFT length 320K: n = 5,262,883
FFT length 384K: n = 5,865,205
FFT length 400K: n = 7,008,845
FFT length 480K: n = 7,288,505
FFT length 512K: n = 8,694,807

k=49:
FFT length 288K: n = 4,431,064
FFT length 320K: n = 4,945,072
FFT length 384K: n = 5,512,082
FFT length 400K: n = 6,585,098
FFT length 480K: n = 6,847,102
FFT length 512K: n = 8,165,124
FFT length 576K: n = 8,718,132
4) Message boards : Fermat Divisor Search : Fermat Divisor Search (Message 132702)
Posted 34 days ago by Profile MyrskylyhtyProject donor
Ooh, more fancy tables.

How often will you update that table? 1 % or some other increment?
5) Message boards : Storm message board (Message 132128)
Posted 55 days ago by Profile MyrskylyhtyProject donor
Maybe Robish you could use up some of that Irish luck and grab a GFN18 or a few :D
6) Message boards : Storm message board (Message 132127)
Posted 55 days ago by Profile MyrskylyhtyProject donor
It's also been like 8 months since last GFN18! :D

Between 2016-2018 it was a prime every few months (21 primes total). That translates to that this we should have found like 5 primes normally.
7) Message boards : Storm message board (Message 127761)
Posted 221 days ago by Profile MyrskylyhtyProject donor
When in doubt, use the SI-units:

2 gigacredits

Congrats!
8) Message boards : Storm message board (Message 126649)
Posted 244 days ago by Profile MyrskylyhtyProject donor
do you know how Jean program works?

would be useful for some primes that I have

I'm talking about this:
http://jpenne.free.fr/index2.html

this is a LLR primlality test, and I don't know how it works


It is quite similar test to Lucas-Lehmer test. Numberphile has a nice video on it: https://www.youtube.com/watch?v=lEvXcTYqtKU (See also here: https://en.wikipedia.org/wiki/Lucas%E2%80%93Lehmer_primality_test)

To upgrade it into Lucas-Lehmer-Riesel test, some info is here https://en.wikipedia.org/wiki/Lucas%E2%80%93Lehmer%E2%80%93Riesel_test

Most likely the LLR program itself has a lot of optimizations, e.g. using FFT to multiply.
9) Message boards : Proth Prime Search : Where are PPS mega k=15 to 99? (Message 126563)
Posted 246 days ago by Profile MyrskylyhtyProject donor
PPS Mega started on PRPNet, that's where those low-k candidates were tested. We never felt any great need to DC them. PPS Mega was then n=3.322M-3.6M.

k=3 is tested in 321
k=5 and k=7 were tested to n=6M years ago (I have no idea why)
k=9 was tested to n=4M years ago.
k=11-99 will start again at n=3.6M

The next PPS Mega candidate file to be loaded starts at n=3.6M so we'll soon have data on the stats page for those k's. I'm sure we'll be loading that during TdP.


Thanks for the info! I also talked about k=15-99 in my thread Status and strategy for small k values, and now these k appear on the Stats Mega LLR page! Will they start from n=3.32M? /JeppeSN


From your linked thread: "k=11-1199 will start being tested in MEGA at n=3.6M+ the next time we need to load work there"
10) Message boards : Proth Prime Search : Where are PPS mega k=15 to 99? (Message 126509)
Posted 247 days ago by Profile MyrskylyhtyProject donor
Here's some benchmarks on FFT size = 200K on the i7-7700K (k=11, n=3600003):

4 tasks, -t1, 0.69 ms per bit /4 = 0.1725 ms per bit "overall"
2 tasks, -t2, 0.48 ms per bit /2 = 0.24 ms per bit "overall"
1 task, -t4, 0.28 ms per bit

For comparison, with FFT = 256K, k=1199, n=3600003

4 tasks, -t1, 0.85 ms per bit / 4 = 0.2125 ms per bit "overall"
2 tasks, -t2, 0.43 ms per bit = 0.215 ms per bit "overall"
1 task, -t4, 0.233 ms per bit

Interestingly, the lower FFT size is much slower with multithreading, which really feels counter-intuitive. So keep this in mind when selecting multithreading for your machine. I'm definately going with -t1 on the i7-7700K.


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