Re: Mersenne: Re: primes source

1999-09-19 Thread poke


 I would NOT encourage using the gpl for this, it's far too restrictive,
 and the fact that the security stuff isn't included in the public code
 would actually be in direct violation of it.

I am curious, what about the GPL do you find restrictive?

-Chuck

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Re: Mersenne: Factors Everywhere

1999-09-19 Thread Conrad Curry



On Sat, 18 Sep 1999, Eric Hahn wrote:

   What I'm looking for is the following two items for *all*
 Mersenne numbers 2^p-1 where p is prime and p1:

  It can be proven that there are an infinite number of these.


   1) All known factors (including, but not limited to,
  the smallest known factor (noted if it isn't))
   2) Largest potential factor attempted
   I ask that the two items are human-readable at the
 very least.

  Will Edgington maintains this information, but it may be
hundreds of megabytes in size.  If a website, such as
Entropia, has the space it will be useful to make this database
available (in many small compressed files) so that others may
use it.


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Re: Mersenne: Factors Everywhere

1999-09-19 Thread Eric Hahn


   What I'm looking for is the following two items for *all*
 Mersenne numbers 2^p-1 where p is prime and p1:

  It can be proven that there are an infinite number of these.

Yeah, right, I knew that...  I guess I should've clarified
and said for all of them that the information is known :(  
If no information is known where p100M, then what can I do??

   1) All known factors (including, but not limited to,
  the smallest known factor (noted if it isn't))
   2) Largest potential factor attempted
   I ask that the two items are human-readable at the
 very least.

  Will Edgington maintains this information, but it may be
hundreds of megabytes in size.  If a website, such as
Entropia, has the space it will be useful to make this database
available (in many small compressed files) so that others may
use it.

Isn't the majority of the information he has in
machine-readable format though??  I can't make much use
of it, if I can't read it...

Eric Hahn

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Re: Mersenne: primes source

1999-09-19 Thread Conrad Curry



On Sat, 18 Sep 1999, George Woltman wrote:

 At 03:01 PM 9/18/99 -0400, Darxus wrote:

 I have a question though.  Why make the Linux source dependant on code
 which needs to be assembled under DOS, when there is an assembler for
 Linux (as) ?
 
 There is a ton of assembly source code.  Converting it from one syntax
 to another would be a great deal of work - and possibly error prone.
 As of two years ago there was not a tool to do the conversion automatically.

  It would be easier to convert the source from MASM to NASM.  Both use
intel syntax.  NASM is free and its source code available.  This is a list
of the object formats it supports.

  * bin   flat-form binary files (e.g. DOS .COM, .SYS)
aout  Linux a.out object files
aoutb NetBSD/FreeBSD a.out object files
coff  COFF (i386) object files (e.g. DJGPP for DOS)
elf   ELF32 (i386) object files (e.g. Linux)
as86  Linux as86 (bin86 version 0.3) object files
obj   MS-DOS 16-bit/32-bit OMF object files
win32 Microsoft Win32 (i386) object files
oldrdfRelocatable Dynamic Object File Format v1.1
rdf   Relocatable Dynamic Object File Format v2.0
ieee  IEEE-695 (LADsoft variant) object file format

  The NASM homepage is http://www.web-sites.co.uk/nasm/index.html

  There are several programs that can convert between intel and gas, but
usually require some help in converting.  One that can convert between
NASM or MASM or Gas is at http://hermes.terminal.at/intel2gas/

  Though if the object file is available and can be converted, I don't
see the advantage of compiling from the source.


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Re: Mersenne: primes source

1999-09-19 Thread Jason Stratos Papadopoulos

On Sun, 19 Sep 1999, Conrad Curry wrote:

   There are several programs that can convert between intel and gas, but
 usually require some help in converting.  One that can convert between
 NASM or MASM or Gas is at http://hermes.terminal.at/intel2gas/

Note that this program was designed to convert from gas to nasm;
conversion from nasm to gas is spotty, and the data files used needed
extensive modification to even nearly get floating point in gas correct.
I can make the changes available, but this program is not ready for
wholesale conversion of very large amounts of Intel floating point source.

jasonp

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Mersenne: Re: primes source

1999-09-19 Thread Steinar H. Gunderson

On Sun, Sep 19, 1999 at 03:02:34AM -0500, Conrad Curry wrote:
  Though if the object file is available and can be converted, I don't
see the advantage of compiling from the source.

The main advantage the ability to change it in any way, especially if you
don't _have_ MASM at all (ie. building with free tools only).

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Mersenne: Factor of 2^(2^31-1)-1 found ($)

1999-09-19 Thread Lucas Wiman

All (and especially Chris),

Yesterday (and the day before), I went to the Illinois number theory conference.
There (2nd talk of yesterday) J. P. Selfridge announced that he would
give away $1000 US for any factor found of a number which ought to be 
prime (he provided a list).  On that list was 2^(2^31-1)-1.

I began searching for a factor of this number in mersfacgmp at around
12:10 Central standard time.  I thought that mersfacgmp was malfunctioning,
because it terminated too quickly, but I was wrong, it had found a factor!
295257526626031 divides 2^(2^31-1)-1, I have confirmed it in 3 different
programs.  Just to make sure that I haven't gone off the deep end, could
Chris Caldwell confirm that he actually offered a prize for this number, and
could the rest of you confirm that it is an actual factor?  

Also, Chris, I lost the sheet that had everyone's email address' at the
conference, could you send me J.P. Selfridge's email address?

Thank you,
Lucas

To guard against errors in transmitions the factor is 295257526626031
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Mersenne: Re: Factor of 2^(2^31-1)-1 found ($

1999-09-19 Thread Lucas Wiman

Oopsy.  That should have read J. L. Selfridge

-lucas
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Mersenne: Re: Factor of 2^(2^31-1)-1 found ($)

1999-09-19 Thread Chris Nash

Hi Lucas

 Yesterday (and the day before), I went to the Illinois number theory
conference.
 There (2nd talk of yesterday) J. P. Selfridge announced that he would
 give away $1000 US for any factor found of a number which ought to be
 prime (he provided a list).  On that list was 2^(2^31-1)-1.
 To guard against errors in transmitions the factor is 295257526626031

p=295257526626031
I took 2, and squared it 31 times mod p. And got the result

2^(2^31)=2 mod p

Congratulations Lucas, it is indeed a factor of 2^(2^31-1)-1 well done!
Had it already been shown that M(M(p)) is not necessarily prime?

Chris Nash
Lexington KY
UNITED STATES


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Re: Mersenne: primes source

1999-09-19 Thread John R Pierce

   It would be easier to convert the source from MASM to NASM.  Both use
 intel syntax.  NASM is free and its source code available.  This is a list
 of the object formats it supports.

if I recall correctly, the assembler code also makes extensive use of the
MASM macro facilities to generate highly repetitious code sequences.  Do
NASM's macros work the same as MASM's?  There are a lot of subtle things
going on in MASM when you get into nested macros and parameter expansions
and so forth.

-jrp


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Re: Mersenne: Re: primes source

1999-09-19 Thread Henrik Olsen

On Sun, 19 Sep 1999, poke wrote:
  I would NOT encourage using the gpl for this, it's far too restrictive,
  and the fact that the security stuff isn't included in the public code
  would actually be in direct violation of it.
 
 I am curious, what about the GPL do you find restrictive?

A programmer trying to use gpl'ed code for part of a program automatically
loses his right to deside on which licence to use on the rest, that's the
fundamental restriction I dislike about it.

I like the general idea, but there are clauses in the licence that 
restricts my freedom to decide on the licence for code I developed.

Note that this does NOT apply for the lgpl (L=Library), which allows
linking code without forcing the licence, but Stallman has publically
announced that the lgpl should not be used for future GNU libraries,
because using the gpl will force more people into free software.


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Re: Mersenne: Factor of 2^(2^31-1)-1 found ($)

1999-09-19 Thread Chris Caldwell

On Sun, 19 Sep 1999, Lucas Wiman wrote:
 All (and especially Chris),
 
 Yesterday (and the day before), I went to the Illinois number theory conference.
 There (2nd talk of yesterday) J. P. Selfridge announced that he would
 give away $1000 US for any factor found of a number which ought to be 
 prime (he provided a list).  On that list was 2^(2^31-1)-1.

I will check with him on what he meant--I notice at least one other number
on his list is already factored.  I will post the revised list here as
soon as I get it. 

Chris

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Mersenne: M(M(127)) and other M(M(p))

1999-09-19 Thread Chris Nash

Hi folks,

After Lucas Wiman's (re)discovery of the factor of M(M(31)), I made some
comment about M(M(p)), something which of course has been long known to not
always be a prime whenever M(p) is. (M(M(13)) is the first counterexample
and even has a factor found by Keller).

Of course, the sequence that still remains unknown is

2
M(2)=3
M(3)=7
M(7)=127
M(127)=170141183460469231731687303715884105727
M(170141183460469231731687303715884105727)=???

the first five of which are prime and the nature of the last still unknown
(hardly surprising!). I noticed Lucas' search found the factor of
M(M(31)) reasonably quickly, a factor which isn't that large a multiple of
M(31) itself.

I checked Chris Caldwell's pages on this, and Curt Noll's trial-factored
M(M(127)) to 5.10^50, surprisingly low considering the size of M(127)
itself, I noticed many other M(M(p)) as listed in
http://www.garlic.com/~wedgingt/MMPstats.txt have only been tested to very
low limits indeed.

I wondered why there wasn't more work done on these - though I understand
it's very hard to motivate people when Guy's law of small numbers no doubt
applies, but everything M(M(61)) and above is currently unknown. It would be
nice to see a few more results there.

Chris


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Re: Mersenne: M(M(127)) and other M(M(p))

1999-09-19 Thread Lucas Wiman

 Of course, the sequence that still remains unknown is
 
 2
 M(2)=3
 M(3)=7
 M(7)=127
 M(127)=170141183460469231731687303715884105727
 M(170141183460469231731687303715884105727)=???

Yes, this sequence is interesting, but if someone finds a way to prove/
disprove the primality of M(M(127)), I think that would be far more 
significant than actually proving/disproving that specific number prime.
(Assuming you don't find a factor, that is).

 I checked Chris Caldwell's pages on this, and Curt Noll's trial-factored
 M(M(127)) to 5.10^50, surprisingly low considering the size of M(127)
 itself, I noticed many other M(M(p)) as listed in
 http://www.garlic.com/~wedgingt/MMPstats.txt have only been tested to very
 low limits indeed.

The reason is relativly clear: the work of checking *even one* factor of
M(M(p)) is greater than the work required for an LL test on that number.
This is because of the need for p squarings modulo some number greater
than M(p).  

 I wondered why there wasn't more work done on these - though I understand
 it's very hard to motivate people when Guy's law of small numbers no doubt
 applies, but everything M(M(61)) and above is currently unknown. It would be
 nice to see a few more results there.

I'm guessing that if a more optimized program were created, then perhaps
there would be more interest.  The Selfridge prize for these numbers could
help.  ...However, we have no way of knowing wether or not these numbers are
prime, unless we find a factor.  Interestingly enough, when we find the next
Mersenne prime, searching for a factor of M(M(p)) might allow us to find an
even bigger prime.  If for example, 6*M(p)+1 divides M(M(p)), then it must
be prime!  

Wait, that might just be the reason to search!  Will only searched up to
k=4 for M(M(6972593)), but if 2*k*M(p)+1 divides M(M(p)), then you've just
beaten the world record!  Non-Mersenne's might once again grace the top
10 list! 

-Lucas

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Re: Mersenne: M(M(127)) and other M(M(p))

1999-09-19 Thread Jeff Woods

At 08:51 PM 9/19/99 -0400, you wrote:

prime, unless we find a factor.  Interestingly enough, when we find the next
Mersenne prime, searching for a factor of M(M(p)) might allow us to find an
even bigger prime.  If for example, 6*M(p)+1 divides M(M(p)), then it must
be prime!

Which one must be prime?   6*M(p)+1, or M(M(p))?

And why?   Enquiring minds, and all   Thanks!

Wait, that might just be the reason to search!  Will only searched up to
k=4 for M(M(6972593)), but if 2*k*M(p)+1 divides M(M(p)), then you've just
beaten the world record!  Non-Mersenne's might once again grace the top
10 list!

An interesting concept -- what sort of time factor would it take to prove 
such a thing with an average computer?   
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Re: Mersenne: M(M(127)) and other M(M(p))

1999-09-19 Thread Chris Nash

 even bigger prime.  If for example, 6*M(p)+1 divides M(M(p)), then it must
 be prime!

Before anybody gets overexcited at the last posting...

It is TRUE that if 2k.M(p)+1 divides M(M(p)), M(p) is prime, and k2M(p)+2,
then 2k.M(p)+1 is prime.

However, unless I'm mistaken, non-divisibility does not prove compositeness.
You could walk past a prime (in fact, you'd expect to walk past several) and
you'd never know...

Chris


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Re: Mersenne: M(M(127)) and other M(M(p))

1999-09-19 Thread Chris Nash

Hi there Lucas...

 The reason is relativly clear: the work of checking *even one* factor of
 M(M(p)) is greater than the work required for an LL test on that number.
 This is because of the need for p squarings modulo some number greater
 than M(p).

Yes, however there is a rather curious combination of effects going on when
testing these numbers. To test if x is a factor of M(M(p)) requires p
squarings mod x, but p is a little less than log2(x). Admittedly, we're only
testing for factors, but there's a curious side effect of the test...

 prime, unless we find a factor.  Interestingly enough, when we find the
next
 Mersenne prime, searching for a factor of M(M(p)) might allow us to find
an
 even bigger prime.  If for example, 6*M(p)+1 divides M(M(p)), then it must
 be prime!

Oh, you can do much better than that... Let q=M(p), a prime. Now any factor
of M(q) is of the form 2kq+1. Provided 2kq+1(2q+1)(2q+1), ie k2q+2, if
2kq+1 divides M(q), then 2kq+1 is prime. In theory then this sort of factor
test can prove the primality of a number up to TWICE THE SQUARE of M(p), yet
the proof still only requires only p squaring operations (admittedly, to a
slightly less pleasant modulus, but readily optimizable). Of course, the
downside is, one has no idea how far you'd need to search (or even if such a
number exists, M(M(p)) could be prime and you'd never know it) - the upside
is, you might get lucky very quickly...

 Wait, that might just be the reason to search!  Will only searched up to
 k=4 for M(M(6972593)), but if 2*k*M(p)+1 divides M(M(p)), then you've just
 beaten the world record!  Non-Mersenne's might once again grace the top
 10 list!

Steady on, there are a few non-Mersennes hanging on in there :) But this
form is very reminiscent of the Miller/Wheeler record (the first one of the
electronic age), 180.M(127)^2+1. I for one wouldn't object to dedicating a
few cycles here and there to find a factor of M(M(1257787)) and who knows,
find the largest known non-GIMPS prime...

Chris



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RE: Mersenne: GIMPS client output

1999-09-19 Thread Rick Pali

From: Darxus

 Iteration: 164000 / 8410531 [1%].  Clocks: 115665753 = 0.496 sec.

 Might be nice to display the percentage out to an accuracy that
 changes every hundred iterations.

If you're using version 19, add "PercentPrecision=3" to the prime.ini file.
If you want more than three decimal places, change the number...I believe
it'll go up to six. I believe that four should be sufficient as even
M33219281 changes every three or four hundred iterations with three places
displayed.

Rick.
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Re: Mersenne: GIMPS client output

1999-09-19 Thread Lucas Wiman

 Might be nice to display the percentage out to an accuracy that changes
 every hundred iterations.  Hmm, looks like that's an integer of the
 percentage, not rounded.  Guess it doesn't matter.  For the one I'm
 working on it looks like 3 decimal places would be needed to see a change
 every 100 iterations.

This is changed in V19 (currently in Beta).  I believe (George correct
me if I'm wrong) that you can specify it up to 6 decimal places.

-Lucas
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Re: Mersenne: GIMPS client output

1999-09-19 Thread Eric Hahn


Iteration: 164000 / 8410531 [1%].  Clocks: 115665753 = 0.496 sec.

Might be nice to display the percentage out to an accuracy that changes
every hundred iterations.  Hmm, looks like that's an integer of the
percentage, not rounded.  Guess it doesn't matter.  For the one I'm
working on it looks like 3 decimal places would be needed to see a change
every 100 iterations.

v19 allows this by manually adding 'PercentPrecision=' to the
PRIME.INI file (Prime95 must be stopped and exited before
editing, and then restarted).  The valid range after the '='
is 0 to 6, therefore you can have it say:

Iteration: 164000/8410531 [1.949936%]. Per iteration time: 0.496...
Iteration: 164100/8410531 [1.951125%]. Per iteration time: 0.496...

Mind you, even at the limit of v19 (79.3M), setting it to a
value of 4, and having screen outputs at every 100 iterations,
will still cause the value to increase (although by 0.0001%)

Eric Hahn

P.S. At the 79.3M range, you'll probably not want to set it
at 100 iterations...  Per iteration time on 266MHz PII with
64MB RAM is 58.781 seconds!!!  (Yes, it's true, but I'm also
just checking to see if anybody's awake :))


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RE: Mersenne: GIMPS client output

1999-09-19 Thread Rick Pali

From: Eric Hahn

 P.S. At the 79.3M range, you'll probably not want to set it
 at 100 iterations...  Per iteration time on 266MHz PII with
 64MB RAM is 58.781 seconds!!!

The only question that comes to mind is if you had to plough through
factoring before you got to the LL test...but then I realise that you still
wouldn't be done if that were true.

I signed up for an exponent in the 33mil range and the factoring alone took
13 days on a P3-500. I'd originally does it for testing purposes, but after
that I've just got to let it continue. :-)

In a year's time, I'd love to see some numbers on how many signed up for tem
million digit numbers and later quit for smaller exponents...

Rick.
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