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-   -   Aouessare-El Haddouchi-Essaaidi "test": "if Mp has no factor, it is prime!" (https://www.mersenneforum.org/showthread.php?t=20098)

wildrabbitt 2015-03-05 17:30

Aouessare-El Haddouchi-Essaaidi "test": "if Mp has no factor, it is prime!"
 
Hi,

I'm not sure whether this has been discussed. I searched for it here on the forums but didn't find anything.

I'm expecting that it's naïve to think it's not known about here especially since there was a post about this
on the mailing list about a year ago.

The post was about a new way of testing whether or not Mersenne numbers are prime or not. The post included
a link to this article :

[URL]http://ijcaonline.org/archives/volume100/number3/17505-8053[/URL]

I was half expecting a new program to be in use by now by the GIMPS and I don't believe one is so I'm starting to wonder
why (since the document clearly outlines the details and is mathematically sound).

So can someone update me on the effect this news had on the mersenne.org community - i.e what the response was,
and if there are any plans to use this algorithm.

Dubslow 2015-03-05 18:04

[url]http://www.mersenneforum.org/showthread.php?p=381194[/url]

That article, the test, isn't worth the figurative paper it's printed on.

petrw1 2015-03-05 19:10

Yes MP13 does only take 4 iterations ...
 
... to determine it is prime vs 11 iterations for Prime95... WOW?!?!?!?

However, it took 1,525 iterations for MP59 to find the first factor
748 iterations to determine MP31 is prime

and it quickly gets much worse.

wildrabbitt 2015-03-05 20:13

Thanks Guys.

So is it just the claim that it's more efficient CPU time - wise that's wrong ?

Does the algorithm actually work?

There was no proof on the paper so I'm unable to even attempt to work the answer out for myself.

Dubslow 2015-03-05 20:33

[QUOTE=wildrabbitt;397102]Thanks Guys.

So is it just the claim that it's more efficient CPU time - wise that's wrong ?

Does the algorithm actually work?

There was no proof on the paper so I'm unable to even attempt to work the answer out for myself.[/QUOTE]

Read the other thread I linked. The algorithm is basically trial factoring, like mfakt*, except done really really really really poorly.

petrw1 2015-03-05 20:34

[QUOTE=wildrabbitt;397102]Thanks Guys.

So is it just the claim that it's more efficient CPU time - wise that's wrong ?

Does the algorithm actually work?

There was no proof on the paper so I'm unable to even attempt to work the answer out for myself.[/QUOTE]

Using Excel I was able to verify that it works at least up to MP61.....a LONG LONG way from where Prime95 is currently

wildrabbitt 2015-03-05 20:41

Without proof it really is useless except to them if they've got one, but why would they keep the proof secret?

Batalov 2015-03-05 22:17

The proof is obvious, however the test is impractical. (I am trying to use only nice words.)

It is important to know that "ijcaonline" is a [URL="http://scholarlyoa.com/individual-journals/"]predatory "journal"[/URL] that publishes anything as long as the submitters pay the required fee. As such, it should be avoided for reading (and as for writing/publishing - only if one likes to publish on the walls of public restrooms; it's the same sort of thing).

ewmayer 2015-03-05 22:47

[QUOTE=wildrabbitt;397107]Without proof it really is useless except to them if they've got one, but why would they keep the proof secret?[/QUOTE]

The point is, even with proof of correctness the test is useless in practice.

In theory I can do a rigorous '1-iteration' test of any M(p) by simply feeding it to e.g. the Pari 'factor' command. In practice, once p gets larger than a few hundred bits, the needed runtime becomes impractically large.

Uncwilly 2015-03-06 00:30

[QUOTE=Batalov;397117]It is important to know that "ijcaonline" is a [URL="http://scholarlyoa.com/individual-journals/"]predatory "journal"[/URL] that publishes anything as long as the submitters pay the required fee.[/QUOTE]Same idea
[QUOTE=rogue;396101][URL="http://www.fastcompany.com/3041493/body-week/why-a-fake-article-cuckoo-for-cocoa-puffs-was-accepted-by-17-medical-journals"]WHY A FAKE ARTICLE TITLED "CUCKOO FOR COCOA PUFFS?" WAS ACCEPTED BY 17 MEDICAL JOURNALS[/URL][/QUOTE]

science_man_88 2015-03-06 02:11

did I do the math correct ?
 
I know I shouldn't play with this, However I manipulated the equation in Theorem 1 to:

[TEX]k>(2np^2-2np+\frac{3}{2}p)[/TEX] where k is such that 2*k*p+1 is Mp I was thinking of manipulating it more, but if I've messed up already it's pointless to try to extrapolate further. EDIT: I think I messed up the +3/2 part I think it should be -3/2 now that I looked over my manipulation on paper. EDIT2: I found a fatal error I failed to correct further up if only I hadn't gone through 27 steps.


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