Proth primes with k = 1281979 - Page 2

bur · 2021-05-03, 07:40

No new primes for n < 3,600,000

Largest n in progress = 3,875,000
# of digits = 1,166,500 (rank: ~ 325)
FFT size = 400k
Avg. time = 4970 s

Smallest n in progress = 3,600,000
# of digits = 1,085,000 (rank: ~ 395)
FFT size = ---k
Avg. time = ---- s

Around July all sieved candidates of n < 4,100,000 should have been tested. I'm not so optimistic anymore that a prime will turn up...

bur · 2021-05-29, 07:06

Things progressed much faster than I expected, the last batch 4,095e6 < n < 4,100e6 will be assigned to a core today and everything should be finished until June, 10th.

If there will be no prime in these last few numbers, I'll continue by sieving the proth side to higher n and doing LLR on-the-fly depending on sieve/LLR times as LaurV suggested.

According to prime95 I'll be able to continue single-threaded until an FFT size of 640k is reached which will be around n = 5.6e6, which agrees nicely with the 5.3 MB of L3 each core has. I just hope a prime will turn up before testing becomes really slow. I'm set on finding a mega prime for this k though. :D

bur · 2021-06-11, 10:59

All n < 4,100,000 have been tested, no new primes other than the ones already posted.

Currently I'm sieving in the range of 4,100,000 < n < 10,000,000.

Smallest p-P range in progress: 87E12-107E12
Avg. time per factor: 810 s

Largest p-P range in progress: 310E12-330E12
Avg. time per factor: 3160 s

Remaining candidates: 100,936 / 5,900,000 (1.71%)

Est. time per LLR test of smallest candidate: 5600 s (n = 4,100,014)

bur · 2021-07-20, 17:31

Quick update, no new primes...

All n < 4,300,000 have been tested.

n < 10,000,000 sieved up to 570E12 (10,000 s / factor)

Approximately 90,000 candidates remain.

Largest LLR-test currently running:
n = 4,450,000
FFT = 448k
6200 s / test
Caldwell entry rank: 290

If the LLR-runtime would increase strictly quadratic, then it'll take to around n = 5,600,000 until an LLR test takes again as long as sieving to eliminate a candidate. As a very rough estimate that should take about 7 months on the 10 core.

And when will the next prime appear? Judging from Primegrid's results on other prime k values it can be a looong time.

bur · 2021-08-27, 17:14

To keep up with the roughly monthly updates and since it's been one year now since I started searching this k, here are the current stats:

As always, no new prime.

All n < 4,600,000 have been tested.

Largest LLR-test currently running:
n = 4,790,000
FFT = 512k
7500 s / test
Caldwell entry rank: 274

bur · 2021-11-22, 16:32

Once again, a status update with no new prime:

Sieving
All n < 10,000,000 have been sieved to 800e12.
Last reported time per factor: approx. 12,000 s

76,167 candidates (1.6%) are left in the range 5,250,000 < n < 10,000,000.

LLR
All n < 5,250,000 have been tested.

Smallest LLR-test currently running:
n = 5.25M
FFT = 560k
duration = 9975 s / test
digits = 1.58M
Caldwell entry rank: 254

Largest LLR-test currently running:
n = 5.36e6
FFT = 560k
duration = 10100 s / test
digits = 1.61M
Caldwell entry rank: 252

rogue · 2021-11-22, 17:09

If you have a GPU, use srsieve2cl for sieving. Depending upon the GPU, it might be faster than sr1sieve. I have a mid-range GPU and it is 5x faster than sr1sieve on the same CPU.

dannyridel · 2021-11-24, 00:51

Quote:

Originally Posted by rogue

If you have a GPU, use srsieve2cl for sieving. Depending upon the GPU, it might be faster than sr1sieve. I have a mid-range GPU and it is 5x faster than sr1sieve on the same CPU.

Where can srsieve2cl be obtained?

rogue · 2021-11-24, 15:23

Quote:

Originally Posted by dannyridel

Where can srsieve2cl be obtained?

It is part of mtsieve and can be found here: https://sourceforge.net/projects/mtsieve/

dannyridel · 2021-11-25, 00:17

Quote:

Originally Posted by rogue

It is part of mtsieve and can be found here: https://sourceforge.net/projects/mtsieve/

Great! Thanks.

Happy5214 · 2021-11-26, 00:05

Quote:

Originally Posted by rogue

If you have a GPU, use srsieve2cl for sieving. Depending upon the GPU, it might be faster than sr1sieve. I have a mid-range GPU and it is 5x faster than sr1sieve on the same CPU.

Not to hijack this thread, but based on personal experience, I've had trouble getting my GeForce RTX 2060 to sieve faster with srsieve2cl than my Intel Core i7-10875H running 8 threads with sr1sieve. In fact, it's not even close with my Riesel data (at least 2-to-1 IIRC).

2021-05-03, 07:40	#12
bur Aug 2020 796581e-4;32539e-3 2⁴×41 Posts	No new primes for n < 3,600,000 Largest n in progress = 3,875,000 # of digits = 1,166,500 (rank: ~ 325) FFT size = 400k Avg. time = 4970 s Smallest n in progress = 3,600,000 # of digits = 1,085,000 (rank: ~ 395) FFT size = ---k Avg. time = ---- s Around July all sieved candidates of n < 4,100,000 should have been tested. I'm not so optimistic anymore that a prime will turn up... Last fiddled with by bur on 2021-05-03 at 07:49

2021-05-29, 07:06	#13
bur Aug 2020 796581e-4;32539e-3 1220₈ Posts	Things progressed much faster than I expected, the last batch 4,095e6 < n < 4,100e6 will be assigned to a core today and everything should be finished until June, 10th. If there will be no prime in these last few numbers, I'll continue by sieving the proth side to higher n and doing LLR on-the-fly depending on sieve/LLR times as LaurV suggested. According to prime95 I'll be able to continue single-threaded until an FFT size of 640k is reached which will be around n = 5.6e6, which agrees nicely with the 5.3 MB of L3 each core has. I just hope a prime will turn up before testing becomes really slow. I'm set on finding a mega prime for this k though. :D Last fiddled with by bur on 2021-05-29 at 07:08

2021-08-27, 17:14	#16
bur Aug 2020 796581e-4;32539e-3 656₁₀ Posts	To keep up with the roughly monthly updates and since it's been one year now since I started searching this k, here are the current stats: As always, no new prime. All n < 4,600,000 have been tested. Largest LLR-test currently running: n = 4,790,000 FFT = 512k 7500 s / test Caldwell entry rank: 274 Last fiddled with by bur on 2021-08-27 at 17:15

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2021-06-11, 10:59	#14
bur Aug 2020 796581e-4;32539e-3 1220₈ Posts	All n < 4,100,000 have been tested, no new primes other than the ones already posted. Currently I'm sieving in the range of 4,100,000 < n < 10,000,000. Smallest p-P range in progress: 87E12-107E12 Avg. time per factor: 810 s Largest p-P range in progress: 310E12-330E12 Avg. time per factor: 3160 s Remaining candidates: 100,936 / 5,900,000 (1.71%) Est. time per LLR test of smallest candidate: 5600 s (n = 4,100,014)

2021-07-20, 17:31	#15
bur Aug 2020 796581e-4;32539e-3 2⁴·41 Posts	Quick update, no new primes... All n < 4,300,000 have been tested. n < 10,000,000 sieved up to 570E12 (10,000 s / factor) Approximately 90,000 candidates remain. Largest LLR-test currently running: n = 4,450,000 FFT = 448k 6200 s / test Caldwell entry rank: 290 If the LLR-runtime would increase strictly quadratic, then it'll take to around n = 5,600,000 until an LLR test takes again as long as sieving to eliminate a candidate. As a very rough estimate that should take about 7 months on the 10 core. And when will the next prime appear? Judging from Primegrid's results on other prime k values it can be a looong time.

2021-11-22, 16:32	#17
bur Aug 2020 796581e-4;32539e-3 290₁₆ Posts	Once again, a status update with no new prime: Sieving All n < 10,000,000 have been sieved to 800e12. Last reported time per factor: approx. 12,000 s 76,167 candidates (1.6%) are left in the range 5,250,000 < n < 10,000,000. LLR All n < 5,250,000 have been tested. Smallest LLR-test currently running: n = 5.25M FFT = 560k duration = 9975 s / test digits = 1.58M Caldwell entry rank: 254 Largest LLR-test currently running: n = 5.36e6 FFT = 560k duration = 10100 s / test digits = 1.61M Caldwell entry rank: 252

2021-11-22, 17:09	#18
rogue "Mark" Apr 2003 Between here and the 15462₈ Posts	If you have a GPU, use srsieve2cl for sieving. Depending upon the GPU, it might be faster than sr1sieve. I have a mid-range GPU and it is 5x faster than sr1sieve on the same CPU.