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Old 2020-07-17, 16:14   #221
Prime95
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Quote:
Originally Posted by kruoli View Post
I'll leave my file on my server and keep a local copy of it. Additionally, I'll keep my ca. 25 GB of temporary files. If those could be helpful for testing, too, I could make them availible, too.
You can delete the 25GB of temporary files
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Old 2020-07-30, 10:08   #222
ZK19
 
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Default Use of res2048 value

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Originally Posted by preda View Post
I know we are used to consider the res64 as the PRP result, but we should realize that res64 is a way of validating the PRP result (by running it again (DC) and comparing res64). While res64 is nice, what really matters and what we're really trying to find by doing PRP is the compositeness status of candidates, not the list of res64 of candidates
.
Hello,

I think this an interesting thread, and very useful work for the project. I wanted to add something that occurred to me, although somewhat late in the discussion now.

As noted, with topK above E the server generally can not cheaply verify the res64 or res2048 value. Although, after successfully verifying the certificate, the result of the PRP test is not in doubt. But if the PRP test indicates composite, and at later dates factor(s) are found, the residue could not be used, e.g. in the scheme R. Gerbicz showed here:

https://www.mersenneforum.org/showthread.php?t=23462

to cheaply show (in some cases) that the cofactor is composite, since the stored res2048 value itself could be invalid.

I'm not qualified nor very experienced in relevant fields, so there is a greater likelihood I've misunderstood. Or I might even have missed that this was considered and discounted as being out of scope (in which case I apologise in advance for not thoroughly enough reading around the topic!)
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Old 2020-07-30, 17:20   #223
Prime95
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Originally Posted by ZK19 View Post
... since the stored res2048 value itself could be invalid.
Thanks for weighing in.

The res64 and res2048 will be correct, but it is not proven.

What does that mean? Prime95 and gpuowl, grab the res64 value and, in prime95's case, the res2048 value on the way to TopK. Barring a program bug, or malicious user changing the available source code, these values will be correct. Proven means 3^TopK was performed correctly and the probably-prime/composite state of the Mersenne number is certain -- immune from program bugs and malicious users.
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Old 2020-07-31, 00:42   #224
retina
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Have you tested the VDF code in P95 with some of the known primes to check that the prime-found code works?

Last fiddled with by retina on 2020-07-31 at 00:42
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Old 2020-07-31, 02:47   #225
Prime95
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Originally Posted by retina View Post
Have you tested the VDF code in P95 with some of the known primes to check that the prime-found code works?
It works on M216091
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Old 2020-07-31, 16:39   #226
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Quote:
Originally Posted by retina View Post
Have you tested the VDF code in P95 with some of the known primes to check that the prime-found code works?
As I recall, prime95/mprime contain special code preventing new retests on known Mersenne primes. So doing as you suggest involves disabling that in the source code. As far as I know there is no equivalent issue in Gpuowl.
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