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..

[QUOTE=msft;425097]I am not understand this issue.
Why iteration is only 0 or 2 ?
Please anyone explain it to me.[/QUOTE]

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):

[url]http://mersenneforum.org/showthread.php?t=20821&highlight=erroneous[/url]

[QUOTE=firejuggler;425105]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.[/QUOTE]
Thank you very much.

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

[QUOTE=msft;425110]I have one additional request.
Please teach me good err message.[/QUOTE]

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

or

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

[QUOTE=Prime95;425115]"Illegal residue: 0x0000000000000000. See mersenneforum.org for help."

or

"Illegal residue: 0x0000000000000002. See mersenneforum.org for help."[/QUOTE]
Thank you very much.
I need few days.

[QUOTE=chris2be8;425091]What compute capability did you compile CUDALucas for? (always check silly things first)

Chris[/QUOTE]

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.

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

[c]CUFLAGS = -O$(OptLevel) --generate-code arch=compute_20,code=sm_20 --compiler-options=-Wall -I$(CUINC)
[/c]
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.

0x0000000000000000 res is valid if it is the[U][B] last[/B][/U] itération

[QUOTE=Madpoo;425083]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:
[URL="http://www.mersenne.org/M37182127"]M37182127[/URL][/QUOTE]
Poacher! :razz:
(it was legally assigned 2 days ago!)

[QUOTE=bgbeuning;425130]My residue are non-zero after changing this line in the Makefile

[c]CUFLAGS = -O\$(OptLevel) --generate-code arch=compute_20,code=sm_20 --compiler-options=-Wall -I\$(CUINC)
[/c]
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.[/QUOTE]
Fixed it for you. (the dollar bug hits again!)