Anyone plan on trying this project

[SB2]

My project uses k*2^n+1. Really LLR includes PRP in it. LLR does deterministic primality tests for k*2^n-1, while it defaults to normal PRP mode for k*2^n+1 (which is a probablistic probable prime test). Iteration times are roughly the same. However, LLR is buggy while Jean updates it to be fast for certain -1 cases, so please continue using PRP. Shouldn't make a difference, but wouldn't want to jeopardize things. Thankx
regards,
william

I have been active in Paul Underwood's 321 Search,and the 15k Search using LLR exclusively, and have experienced no problems with it. I believe that Jenne's newest build which took advange of some faster code (for small k values) had a few problems, earlier releases are not affected. I've only searched for primes of the form k*2^n-1, other than when running GIMPS, hence the question of the difference in the two programs.

Thanks for the reply, PRP it is then.

[wfgarnett3]

Hi SB2,

Just so I don't give wrong information, are you in my project (i.e. your name appears on webpage). If so, yeah continue using PRP, since we are doing k*2^n+1. If you are not in my project and would like to join, email me as per instruction thread so I may give you a line number.

If you are not in my search but test numbers of the form k*2^n-1, then stick with LLR all the time; don't use PRP. As you know LLR has huge speedup for small k so you want to use that. Plus, even if you aren't using small k mode, stick with LLR because "normal" mode isn't buggy. Plus I like what Jean did with LLR, he used the Lucas-Lehmer Riesel algorithm, so all the numbers you test for k*2^n-1 always report back if composite or prime. When it says prime, it is 100% prime, because LLR always does a deterministic primality test, so it is always correct and proves outright primality. Older PRP uses probablisitc probable prime test (I thinnk) which is 99% accurate, and doesn't prove primality, requiring an extra step of using OpenpFgw for Proth.exe to prove primality.

Hope that helps.

regards,
william

[Keith75]

Yeah, I looked around on the web after posting that and saw how wrong I was. Funny, I would have bet the farm that I saw mine say it had SSE2.
I just love how Intel blasted the 64-Bit AMDs saying they were pointless and not necessary. A few months later they say they are working on them and how wonderful they will be. Sounds like something you would here in an election.

Keith

[SB2]

Hi SB2,

Just so I don't give wrong information, are you in my project (i.e. your name appears on webpage). If so, yeah continue using PRP, since we are doing k*2^n+1. If you are not in my project and would like to join, email me as per instruction thread so I may give you a line number.

If you are not in my search but test numbers of the form k*2^n-1, then stick with LLR all the time; don't use PRP. As you know LLR has huge speedup for small k so you want to use that. Plus, even if you aren't using small k mode, stick with LLR because "normal" mode isn't buggy. Plus I like what Jean did with LLR, he used the Lucas-Lehmer Riesel algorithm, so all the numbers you test for k*2^n-1 always report back if composite or prime. When it says prime, it is 100% prime, because LLR always does a deterministic primality test, so it is always correct and proves outright primality. Older PRP uses probablisitc probable prime test (I thinnk) which is 99% accurate, and doesn't prove primality, requiring an extra step of using OpenpFgw for Proth.exe to prove primality.

Hope that helps.

regards,
william

Thanks for the informative reply. I am not involved with your project yet, but as soon as we can finish off 321 Search to n=1M I will move a couple of the P4's over to your project.