Large range of exponents with small P-1 bounds - Page 4

Viliam Furik · 2021-07-21, 19:55

Quote:

Originally Posted by chalsall

Interestingly, these were all "cleared" by way of C-PRP. But, at the same time, the column showing "Available: P-1" for 104M hasn't changed for days. So, empirically, those candidates I'm doing P-1 on are not the ones included in this column.

You probably noticed that masser found a bunch of exponents in the 100M range that had no P-1 done. Therefore it's them.

It is possible that the server is now confused, and doesn't update their status with the newly done P-1, because the PRP has been done already.

chalsall · 2021-07-21, 20:04

Quote:

Originally Posted by Viliam Furik

It is possible that the server is now confused, and doesn't update their status with the newly done P-1, because the PRP has been done already.

Yes. I was hinting that perhaps those who have access to the code, and the data, might take a look...

Please trust me on this... You don't want LaurV to point out your SPEs...

drkirkby · 2021-07-21, 21:15

Quote:

Originally Posted by kriesel

I did not claim that. Only commented that the bounds seemed quite low to me for all that ram available.

As a test, I tried RAM constraints between 128 MB and 370 GB for P-1 factoring of M105216541. Here are the results. Somewhere between 181 GB and 256 GB, the bounds do not change with increasing RAM. Both 256 GB and 370 GB use the same bounds. The probability of finding a factor does not change significantly above 32 GB.

Code:

128 MB
[Worker #1 Jul 21 21:40] Optimal P-1 factoring of M105216541 using up to 128MB of memory.
[Worker #1 Jul 21 21:40] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:40] Optimal bounds are B1=434000, B2=434000
[Worker #1 Jul 21 21:40] Chance of finding a factor is an estimated 1.19%

256 MB
[Worker #1 Jul 21 21:38] Optimal P-1 factoring of M105216541 using up to 256MB of memory.
[Worker #1 Jul 21 21:38] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:38] Optimal bounds are B1=434000, B2=434000
[Worker #1 Jul 21 21:38] Chance of finding a factor is an estimated 1.19%

512 MB
[Worker #1 Jul 21 21:36] Optimal P-1 factoring of M105216541 using up to 512MB of memory.
[Worker #1 Jul 21 21:36] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:36] Optimal bounds are B1=330000, B2=6504000
[Worker #1 Jul 21 21:36] Chance of finding a factor is an estimated 2.71%

1 GB
[Worker #1 Jul 21 21:34] Optimal P-1 factoring of M105216541 using up to 1024MB of memory.
[Worker #1 Jul 21 21:34] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:34] Optimal bounds are B1=357000, B2=9356000
[Worker #1 Jul 21 21:34] Chance of finding a factor is an estimated 2.97%

2 GB
[Worker #1 Jul 21 21:33] Optimal P-1 factoring of M105216541 using up to 2048MB of memory.
[Worker #1 Jul 21 21:33] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:33] Optimal bounds are B1=372000, B2=11184000
[Worker #1 Jul 21 21:33] Chance of finding a factor is an estimated 3.1%

4 GB
[Worker #1 Jul 21 20:01] Optimal P-1 factoring of M105216541 using up to 4096MB of memory.
[Worker #1 Jul 21 20:01] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:01] Optimal bounds are B1=380000, B2=12579000
[Worker #1 Jul 21 20:01] Chance of finding a factor is an estimated 3.18%

8 GB
[Worker #1 Jul 21 20:17] Optimal P-1 factoring of M105216541 using up to 8192MB of memory.
[Worker #1 Jul 21 20:17] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:17] Optimal bounds are B1=388000, B2=14613000
[Worker #1 Jul 21 20:17] Chance of finding a factor is an estimated 3.29%

16 GB
[Worker #1 Jul 21 20:28] Optimal P-1 factoring of M105216541 using up to 16384MB of memory.
[Worker #1 Jul 21 20:28] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:28] Optimal bounds are B1=403000, B2=16737000
[Worker #1 Jul 21 20:28] Chance of finding a factor is an estimated 3.4%

32 GB
[Worker #1 Jul 21 20:36] Optimal P-1 factoring of M105216541 using up to 32768MB of memory.
[Worker #1 Jul 21 20:36] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:36] Optimal bounds are B1=411000, B2=18628000
[Worker #1 Jul 21 20:36] Chance of finding a factor is an estimated 3.48%

64 GB
[Worker #1 Jul 21 20:40] Optimal P-1 factoring of M105216541 using up to 65536MB of memory.
[Worker #1 Jul 21 20:40] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:40] Optimal bounds are B1=434000, B2=19680000
[Worker #1 Jul 21 20:40] Chance of finding a factor is an estimated 3.54%

128 GB
[Worker #1 Jul 21 20:50] Optimal P-1 factoring of M105216541 using up to 131072MB of memory.
[Worker #1 Jul 21 20:50] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:50] Optimal bounds are B1=426000, B2=20959000
[Worker #1 Jul 21 20:50] Chance of finding a factor is an estimated 3.57%

181 GB - used since sqrt(2) * 128 = 181
[Worker #1 Jul 21 21:22] Optimal P-1 factoring of M105216541 using up to 185364MB of memory.
[Worker #1 Jul 21 21:22] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:22] Optimal bounds are B1=418000, B2=20899000
[Worker #1 Jul 21 21:22] Chance of finding a factor is an estimated 3.56%

256 GB
[Worker #1 Jul 21 20:56] Optimal P-1 factoring of M105216541 using up to 262144MB of memory.
[Worker #1 Jul 21 20:56] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 20:56] Optimal bounds are B1=434000, B2=21339000
[Worker #1 Jul 21 20:56] Chance of finding a factor is an estimated 3.6%

370 GB (maximal practical amount I could use)
[Worker #1 Jul 21 21:03] Optimal P-1 factoring of M105216541 using up to 378880MB of memory.
[Worker #1 Jul 21 21:03] Assuming no factors below 2^76 and 1 primality test saved if a factor is found.
[Worker #1 Jul 21 21:03] Optimal bounds are B1=434000, B2=21339000
[Worker #1 Jul 21 21:03] Chance of finding a factor is an estimated 3.6%

chalsall · 2021-07-21, 21:39

Quote:

Originally Posted by drkirkby

As a test, I tried RAM constraints between 128 MB and 370 GB for P-1 factoring of M105216541. Here are the results.

And... What did you conclude from that empirical?

kriesel · 2021-07-21, 22:09

Bounds would be somewhat higher for the normal case of tests_saved =2 which is what PrimeNet issues.
Estimated or actual stage run times for those different ram settings posted above would be useful info.
As would varying ram for tests_saved=2.

Quote:

Originally Posted by chalsall

And... What did you conclude from that empirical?

Perhaps that beyond 16-64GB/worker there's little or no point to more ram at ~105M exponent. TB/3 might be handy near 1G.

chalsall · 2021-07-21, 22:24

Quote:

Originally Posted by kriesel

Bounds would be somewhat higher for the normal case of tests_saved =2 which is what PrimeNet issues.

Not meaning to put too fine a point on this, but...

Code:

[Work thread Jul 21 09:22] Optimal P-1 factoring of M28677581 using up to 8192MB of memory.
[Work thread Jul 21 09:22] Assuming no factors below 2^73 and 8 primality tests saved if a factor is found.
[Work thread Jul 21 09:22] Optimal bounds are B1=994000, B2=54341000
[Work thread Jul 21 09:22] Chance of finding a factor is an estimated 5.36%

drkirkby seems to be fixated on his sole instance which has a lot of memory.

What he fails to understand is some of us actually have scores of machines. He is, actually, less than even interesting.

Viliam Furik · 2021-07-21, 23:01

Quote:

Originally Posted by chalsall

Please trust me on this... You don't want LaurV to point out your SPEs...

What's that?

chalsall · 2021-07-21, 23:12

Quote:

Originally Posted by Viliam Furik

What's that?

Stupid Programmer Error (SPE).

LaurV has a way of "bumping the queue" in his error reporting...

kriesel · 2021-07-21, 23:38

Not to be confused with SPR (Software Performance Report). A famous one is on the "error" of treating the year 2000 as a leap year, issued around 1983.

chalsall · 2021-07-21, 23:58

Quote:

Originally Posted by kriesel

A famous one is on the "error" of treating the year 2000 as a leap year, issued around 1983.

I was married to my first wife on 2000.02.29.

Once in a four hundred year event. The union lasted less than two of the four year cycles...

PhilF · 2021-07-22, 00:02

Quote:

Originally Posted by chalsall

I was married to my first wife on 2000.02.29.

Once in a four hundred year event. The union lasted less than two of the four year cycles...

Another SPE?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
P-1 on small exponents	markr	PrimeNet	18	2009-08-23 17:23
Large small factor	Zeta-Flux	Factoring	96	2007-05-14 16:59
Problems with Large FFT but not Small FFT's?	RichTJ99	Hardware	2	2006-02-08 23:38
Small range with high density of factors	hbock	Lone Mersenne Hunters	1	2004-03-07 19:51
Small win32 program, range of time to do a TF	dsouza123	Programming	1	2003-10-09 16:04

2021-07-21, 23:38	#42
kriesel "TF79LL86GIMPS96gpu17" Mar 2017 US midwest 153D₁₆ Posts	Not to be confused with SPR (Software Performance Report). A famous one is on the "error" of treating the year 2000 as a leap year, issued around 1983.