Biggest factors found by P-1 - Page 2

chalsall · 2013-10-28, 04:07

Quote:

Originally Posted by TheMawn

Is P-1 guaranteed to give a prime factor?

No.

Uncwilly · 2013-10-28, 05:54

Quote:

Originally Posted by TheMawn

Anyway, I found this one too. M63267157 has a factor: 91234295579487063953720150647 = 2^96.204

I have one at 98.39.

LaurV · 2013-10-28, 09:51

Mine just went out of top some weeks ago, at ~103.xx bits.

TimSorbet · 2013-10-28, 11:57

Quote:

Originally Posted by TheMawn

Is P-1 guaranteed to give a prime factor? Could some of those massive ones be products of two smaller numbers around 2⁷⁴ to 2⁷⁶ or whatever to give 2¹⁵⁰? Just thought of that now.

It can find a composite factor, but those are not generally thought of as being as impressive as a prime factor of the same size. I doubt composite factors are included on GPUto72's "largest 100 factors found" list and, in any case, all of the largest factors mentioned here have been prime.

henryzz · 2013-10-28, 15:07

Most of these aren't twice the size of the tf depth so they will be prime

TheMawn · 2013-10-28, 17:59

Well I was noticing that some of the absolutely massive ones might be but even The Judger's record on GPU72 of 146.45 is too small as it would be 74 + 72.45 and both would have likely been found since his exponent should be TF'ed to 74.

On the other hand, the one George mentioned is 2^173.5 which could easily be a composite factor. That's why I had asked about the prime or composite factor. I hope it's composite because that IS impressive.

Prime95 · 2013-10-28, 18:01

Quote:

Originally Posted by TheMawn

On the other hand, the one George mentioned is 2^173.5 which could easily be a composite factor.

The one I mentioned is only a bit or two above TheJudger's. What is impressive is that it has held the top spot for about a decade.

LaurV · 2013-10-29, 02:30

Quote:

Originally Posted by Prime95

The one I mentioned is only a bit or two above TheJudger's. What is impressive is that it has held the top spot for about a decade.

I know where the misunderstanding is coming from

Code:

gp > log(426315489966437174530195419710289226952407399)/log(2)
%1 = 148.2567576509223079601764086
gp > log(17504141 426315489966437174530195419710289226952407399)/log(2)
%2 = 173.5479572338198927251262281
gp > isprime(426315489966437174530195419710289226952407399)
%3 = 1
gp > isprime(17504141 426315489966437174530195419710289226952407399)
%4 = 0
gp >

Hehe, the "number" contains the factor AND the exponent - there is a small space in the middle

TheMawn · 2013-10-29, 04:39

Oh. I thought that was a typo in the factor. I didn't notice that space separated the exponent and factor.

LaurV · 2013-10-29, 06:11

Quote:

Originally Posted by TheMawn

Oh. I thought that was a typo in the factor. I didn't notice that space separated the exponent and factor.

That is because George always give out too much information

I never give the exponent when I talk about a factor (see "factors found" threads) of mersenne numbers. The exponent is trivial to find if you know the factor.

TheJudger · 2013-10-29, 21:18

Quote:

Originally Posted by TheMawn

How many people do P-1 through GPU72 versus primenet? Is there any strong reason to pick one over the other?

With GPU72 it is easier (faster) to receive a bunch of assignments for manual handling.

Quote:

Originally Posted by TheMawn

Are the big ones from setting bounds to freakishly high numbers or just random luck?

I'm using regular (Prime95s automatic) parameters for B1 and B2. I'm using 1GB or more per worker in stage2.

Oliver

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2013-10-28, 09:51	#14
LaurV Romulan Interpreter "name field" Jun 2011 Thailand 24051₈ Posts	Mine just went out of top some weeks ago, at ~103.xx bits.

2013-10-28, 15:07	#16
henryzz Just call me Henry "David" Sep 2007 Liverpool (GMT/BST) 37·163 Posts	Most of these aren't twice the size of the tf depth so they will be prime

2013-10-28, 17:59	#17
TheMawn May 2013 East. Always East. 11×157 Posts	Well I was noticing that some of the absolutely massive ones might be but even The Judger's record on GPU72 of 146.45 is too small as it would be 74 + 72.45 and both would have likely been found since his exponent should be TF'ed to 74. On the other hand, the one George mentioned is 2^173.5 which could easily be a composite factor. That's why I had asked about the prime or composite factor. I hope it's composite because that IS impressive.

2013-10-29, 04:39	#20
TheMawn May 2013 East. Always East. 11×157 Posts	Oh. I thought that was a typo in the factor. I didn't notice that space separated the exponent and factor.