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Old 2021-08-24, 08:30   #485
kruoli
 
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Next on is a C201. I finished around one and a quarter t55 on it. t60 would take me more than two weeks, so that's heavier than I can lift in a reasonable amount of time, it seems. How high do we want to go? YAFU said t62?

Any help is appreciated!
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Old 2021-08-25, 00:43   #486
swellman
 
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Quote:
Originally Posted by kruoli View Post
Next on is a C201. I finished around one and a quarter t55 on it. t60 would take me more than two weeks, so that's heavier than I can lift in a reasonable amount of time, it seems. How high do we want to go? YAFU said t62?

Any help is appreciated!
I use 0.31*GNFS difficulty to get the ECM test metric, which is t62 in this case. After this week, I can contribute some t60 cycles if you still need them then.
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Old 2021-08-25, 01:58   #487
VBCurtis
 
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My vote (not that you asked for it) is half a t60, then a t60 worth of curves at the t65 level.

C200ish jobs are a whole lot easier and faster than they used to be, so we need less ECM than we used to need.
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Old 2021-08-26, 16:04   #488
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Quote:
Originally Posted by swellman View Post
I can contribute some t60 cycles if you still need them then.
I'd really appreciate that! On Sunday, I'll likely have finished around 15k-18k curves @ B1=260M and 400-500 @ B1=850M from another machine.

After doing ECM and assuming no factors, is this a job for team sieving or for some of the NFS@home queues? In the first case, I'd volunteer for hosting a CADO server and to do the LA in the end. I might need some help with the initial setup since I never ran a CADO server with computers all over the world, only locally. But I am going too far into the future right now, I guess. There is still a good chance that we hit something with ECM until then.

@VBCurtis: I always appreciate input, especially because I have a lot to learn in this field. I guess "t60 worth of curves" refers to the amount of 260M curves?

Last fiddled with by kruoli on 2021-08-26 at 16:04 Reason: Misspelling names is a felony.
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Old 2021-08-26, 16:44   #489
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If you invoke ecm with the -v flag, you'll get a table of curve counts for each t-value in multiples of 5 digits.

So, ecm -v 85e7 will tell you how many curves at B1=850M is worth a t60. Doing so shows me 15391 curves, so my advice was 15k curves at 850M after half a normal t60.

Edit: C201 is simple for the 16-small queue, but if you'd like the experience of hosting a team CADO sieve I'm willing to run clients and advise on management. Should be ~30 core-years of sieving. You'll need 64GB ram for the postprocessing, or plenty of experience using msieve postprocessing after CADO sieving.

Last fiddled with by VBCurtis on 2021-08-26 at 16:46
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Old 2021-08-26, 18:39   #490
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Depending on the progress of the 4788 poly search, I may be able to run some curves at 850M next week.

Quote:
Originally Posted by VBCurtis View Post
You'll need 64GB ram for the postprocessing, or plenty of experience using msieve postprocessing after CADO sieving.
Come on, it's not too hard to convert the poly format and cat all the relations into a msieve.dat.gz file
Msieve postprocessing should fit within 32GB RAM.
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Old 2021-08-26, 20:14   #491
kruoli
 
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Thanks for the explanation, I now understand what you meant originally.

The RAM reqirements can be met. How much efficiency could be gained by running msieve for LA instead of CADO?
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Old 2021-08-26, 20:44   #492
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Quote:
Originally Posted by charybdis View Post
Come on, it's not too hard to convert the poly format and cat all the relations into a msieve.dat.gz file
Msieve postprocessing should fit within 32GB RAM.
Once is "plenty"! :) (sorry for my bad word choice originally)

For the same-sized matrix, msieve LA will run in maybe 50-60% of the time CADO runs. But, CADO filtering makes smaller matrices- for the C207 team sieve, CADO created a matrix around 61M dimensions while msieve on the same data set was 73M dimensions. So, that ate up about half the speed advantage (in very rough terms- I think msieve was 11 weeks while CADO would have been 15ish weeks).
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Old 2021-08-26, 22:10   #493
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Quote:
Originally Posted by kruoli View Post
I'd really appreciate that! On Sunday, I'll likely have finished around 15k-18k curves @ B1=260M and 400-500 @ B1=850M from another machine.
Ok I’ll start some ECM at B1=260M this weekend. I can do about 2k curves per day.

Quote:
Originally Posted by charybdis
Depending on the progress of the 4788 poly search, I may be able to run some curves at 850M next week.
Glad you can play. Personally I don’t care who finds a factor or at what level, but if you start running ECM at 850M early next week just be aware that we will still be running ECM at the t60 level. Race to the finish!
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Old 2021-08-27, 07:50   #494
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While msieve is faster at LA, I often had the problem that cado could build a matrix while msieve couldn't and required more relations.

Depending on the circumstances that might make it faster to use cado for everything, especially if using just a few cores for sieving.
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Old 2021-08-29, 00:54   #495
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I’ll start ECM with B1=260M shortly. I’ll shoot for 10000 curves, then we can regroup later in the week and see where we are.


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