CUDALucas (a.k.a. MaclucasFFTW/CUDA 2.3/CUFFTW)

[firejuggler]

steps for next iteration is
precedent residue (mod P), squared, minus 2, so in case of 0, 0 squared, minus 2 is -2.
-2^2 -2 = 2 and then it loop..

[science_man_88]

Originally Posted by msft

I am not understand this issue.
Why iteration is only 0 or 2 ?
Please anyone explain it to me.

because those are known residues to cause a repeat regardless of the mersenne number being tested see ( so are -1 and 1 but that's a different story):

http://mersenneforum.org/showthread....ight=erroneous

[msft]

Originally Posted by firejuggler

steps for next iteration is
precedent residue (mod P), squared, minus 2, so in case of 0, 0 squared, mius 2, is -2 then -2 squared -2 = 2... and then 2 squared minus 2, is 2.

Thank you very much.

[msft]

I have one additional request.
Please teach me good err message.

[Prime95]

Originally Posted by msft

I have one additional request.
Please teach me good err message.

"Illegal residue: 0x0000000000000000. See mersenneforum.org for help."

or

"Illegal residue: 0x0000000000000002. See mersenneforum.org for help."

[msft]

Originally Posted by Prime95

"Illegal residue: 0x0000000000000000. See mersenneforum.org for help."

or

"Illegal residue: 0x0000000000000002. See mersenneforum.org for help."

Thank you very much.
I need few days.

[airsquirrels]

Originally Posted by chris2be8

What compute capability did you compile CUDALucas for? (always check silly things first)

Chris

Well that did it, I was not aware that the Makefile contained hardcoded compute levels.

We might want to update the error message, or add a check that the card at least meets the Compute capability CUDALucas was compiled with.

[bgbeuning]

My residue are non-zero after changing this line in the Makefile

CUFLAGS = -O$(OptLevel) --generate-code arch=compute_20,code=sm_20 --compiler-options=-Wall -I$(CUINC)

Maybe the program could check if the executable file is not compatible with the
hardware it is running on.

It is running 2 double checks. Will know results in 7 days.

[firejuggler]

0x0000000000000000 res is valid if it is the last itération

[LaurV]

Originally Posted by Madpoo

Well, there have been no less than 3 false positives (2 different users) in the past ~ 16 hours, all from CUDALucas 2.05.1 ...

Even though I'm totally sure they're false positives (2 are from double-checks, making it even more unlikely), I'm still running my own.

One of them is done and it's not prime of course... waiting on the others:
M37182127

Poacher!
(it was legally assigned 2 days ago!)

[LaurV]

Originally Posted by bgbeuning

My residue are non-zero after changing this line in the Makefile

CUFLAGS = -O\$(OptLevel) --generate-code arch=compute_20,code=sm_20 --compiler-options=-Wall -I\$(CUINC)

Maybe the program could check if the executable file is not compatible with the
hardware it is running on.

It is running 2 double checks. Will know results in 7 days.

Fixed it for you. (the dollar bug hits again!)