How exactly does the GIMPS project work?

[mersenne1588]

Hi there,

I would like to know how the GIMPS project exactly works. Let us assume that my computer does the LL first test.

In this case, my computer performs the arithmetic operations 100 percent on its own and only the status of the work is reported to the Prime Net server via the Internet or is the Prime NET Server in the arithmetic operations involved, so that the arithmetic operations are divided (by my computer and the PRIME NET Server), so that here the LL first test is done by several computers?

[retina]

Originally Posted by mersenne1588

In this case, my computer performs the arithmetic operations 100 percent on its own and only the status of the work is reported to the Prime Net server via the Internet ...

This. Only your computer does the work.

Later someone else will double check it and do it all again on their computer.

[paulunderwood]

Originally Posted by mersenne1588

Hi there,

I would like to know how the GIMPS project exactly works. Let us assume that my computer does the LL first test.

In this case, my computer performs the arithmetic operations 100 percent on its own and only the status of the work is reported to the Prime Net server via the Internet or is the Prime NET Server in the arithmetic operations involved, so that the arithmetic operations are divided (by my computer and the PRIME NET Server), so that here the LL first test is done by several computers?

LL first tests are double checked. However PRP tests are preferable; Not only is there Gerbicz error checking, a certificate is produced which means only one test is performed -- unless it is PRP when several LL tests will be done on different hardware with different softwares.

[mersenne1588]

Originally Posted by retina

This. Only your computer does the work.

I suppose, "work" means here any kind of research work (trial factoring, LL first test, LL double check, PRP cofactor test, etc...), right?

[retina]

Originally Posted by mersenne1588

I suppose, "work" means here any kind of research work (trial factoring, LL first test, LL double check, PRP cofactor test, etc...), right?

Yes.

[mersenne1588]

Ok, I understand. Thank you both for your answers.

[Uncwilly]

The work flow goes like this.

We have a list of primes that will be used as the candidate exponents (p) in 2^p-1
Trial factoring and then P-1 factoring are used to eliminate candidates with small factors.
Then the First Time Check is done. (In the past that was an LL test. Now we do PRP with the certificate enhancement which will save the project the cost of a double check for composites. If the PRP test shows that it is a Probable Prime, then the LL tests are done on various CPU architectures by various software types.)
If the FTC shows it is not prime then either the cert is run or a LL double check.

There is a subproject of looking for full factorizations of composite Mersenne Numbers. If we have a known factor, then a PRP is done on the remaining co-factor. If it is a PRP prime, then we are done. If it isn't there are people that will use TF, P-1, then ECM, and eventually a sieve to find all of the factors. Most are content to have a single known factor. Others want to know them all.

[mersenne1588]

Originally Posted by Uncwilly

If the PRP test shows that it is a Probable Prime, then the LL tests are done on various CPU architectures by various software types.)

And what are the names of the various software types?

[LaurV]

Prime 95, Mprime, MLucas, cudaLucas, gpuOwl, gLucas, etc

[Uncwilly]

Originally Posted by LaurV

Prime 95, Mprime, MLucas, cudaLucas, gpuOwl, gLucas, etc

mprime and Prime95 are twins. mprime is for linux and Prime95 for windows.

I think there are a few how brew programs out there too that are used by just one person and are not nearly as fast as the others mentioned.

[PhilF]

Originally Posted by Uncwilly

mprime and Prime95 are twins. mprime is for linux and Prime95 for windows.

I think there are a few how brew programs out there too that are used by just one person and are not nearly as fast as the others mentioned.

Actually, to make mprime the twin of Prime95, it needs to be invoked with the -m and -d options. Typically the command is "./mprime -d -m".

This instructs mprime to start with the menu, and to provide status output while it is running. I think this confuses a lot of new users, because without those options mprime defaults to looking like it is deaf and mute.