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Allen Paschke

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Message 143904 - Posted: 4 Oct 2020 | 20:44:58 UTC

For these 8 projects, hereâ€™s the number of prime numbers discovered in the past 5 years --- 0 for 321, 0 for CUL, 2 for ESP, 5 for GCW, 1 for PSP, 1 for SOB, 1 for TRP and 1 for WOO.

Now that LLR2 is running a â€œshortâ€ double check, using about 1% of the CPU time that the â€œfullâ€ LLR test requires, what are the pros and cons of running LLR2 double checks tasks first, then if LLR2 verifies a prime number, run the â€œfullâ€ LLR task?

If this LLR2 strategy were to work, PrimeGrid could determine if many more numbers are prime in each project:
- Does LLR2 ever not verify a prime number that LLR has discovered?
- I would assume that LLR2 may determine that erroneous numbers are prime numbers, but LLR would verify if itâ€™s a prime number?
- Is there any knowledge of the probability of LLR2 missing a prime number?

Philosophical Question --- Is it better to run many more tasks to try to find a prime number, and possibly missing a prime number OR continue the current more thorough methodology?

Grebuloner
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Message 143905 - Posted: 4 Oct 2020 | 20:59:07 UTC - in response to Message 143904.

The double check tasks are made from the information gathered by the first (long) task. I think quantum computing is required to do it in reverse :).

I think you have LLR vs. LLR2 a little mixed up. The same primality calculation is run by both programs. LLR2 adds additional steps so that the work can be verified as correct in a very short amount of time, as well as some error-handling algorithms, while LLR requires a duplicate and matching complete calculation.

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Michael Goetz
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Message 143906 - Posted: 4 Oct 2020 | 21:07:03 UTC

It's not possible, unfortunately.

Here's the LLR2 work flow:

1) Main task: Does normal calculation, and also saves a mathematical "proof of work". When the task is done, both the normal result (the regular residue) and the proof data are sent to the server.

2) The server processes the proof, creating the data necessary for the DC task and the expected "secret residue".

3) The DC task is run on a host (probably not the same hast that ran the main task, but it doesn't matter if it is), and the result (a residue) is sent back to the server.

4) The server compares the residue produced by the DC task to the secret residue it created in step 2. If they match, then the original task was correct.

It's impossible to run the DC task (step 3) without first running step 2, which creates the data for step 3. And it's impossible to run step 2 without the data from step 1.

The Fast DC isn't really a double check in the normal sense. It is not checking for primality like the main task. It's a verification that the main task is correct. You can't run the verification without first getting the data from the main task.

Think of it like grading a test. You can't grade the test until after the student takes the test.
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Allen Paschke

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Message 143912 - Posted: 4 Oct 2020 | 23:37:56 UTC - in response to Message 143906.

Thank you. That makes alot of sense.

Message boards : General discussion : Philosophical Question