[sage-support] Re: Solve system of non linear equations

2012-12-08 Thread Volker Braun
I take it you mean polynomial equations:

sage: AA.x,y = AffineSpace(GF(2),2)
sage: S = AA.subscheme(x^2+y^2)
sage: S.point_set().points()
[(0, 0), (1, 1)]


On Saturday, December 8, 2012 6:14:19 AM UTC, Santanu wrote:

   I have a system of non linear equations over GF(2). How to solve
 them in Sage? 


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Re: [sage-support] Re: Solve system of non linear equations

2012-12-08 Thread Martin Albrecht
Or compute a Gröbner basis:

sage: P.x,y = BooleanPolynomialRing()
sage: Ideal(x^2 + y^2).groebner_basis()
[x + y]
sage: Ideal(x^2 + y^2).variety()   
[{y: 0, x: 0}, {y: 1, x: 1}]

On Saturday 08 Dec 2012, Volker Braun wrote:
 I take it you mean polynomial equations:
 
 sage: AA.x,y = AffineSpace(GF(2),2)
 sage: S = AA.subscheme(x^2+y^2)
 sage: S.point_set().points()
 [(0, 0), (1, 1)]
 
 On Saturday, December 8, 2012 6:14:19 AM UTC, Santanu wrote:
I have a system of non linear equations over GF(2). How to solve
  
  them in Sage?

Cheers,
Martin

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Re: [sage-support] Re: Solve system of non linear equations

2012-12-08 Thread Santanu Sarkar
Thank you. But when I try to solve
f1=x1 + x2 + x4 + x10 + x31 + x43 + x56 ,
f2=x2 + x3 + x5 + x11 + x32 +x44 + x57,

it becomes very slow. Is there any faster approach like
F4 algorithm available in Sage?



On 8 December 2012 17:25, Martin Albrecht martinralbre...@googlemail.comwrote:

 Or compute a Gröbner basis:

 sage: P.x,y = BooleanPolynomialRing()
 sage: Ideal(x^2 + y^2).groebner_basis()
 [x + y]
 sage: Ideal(x^2 + y^2).variety()
 [{y: 0, x: 0}, {y: 1, x: 1}]

 On Saturday 08 Dec 2012, Volker Braun wrote:
  I take it you mean polynomial equations:
 
  sage: AA.x,y = AffineSpace(GF(2),2)
  sage: S = AA.subscheme(x^2+y^2)
  sage: S.point_set().points()
  [(0, 0), (1, 1)]
 
  On Saturday, December 8, 2012 6:14:19 AM UTC, Santanu wrote:
 I have a system of non linear equations over GF(2). How to solve
  
   them in Sage?

 Cheers,
 Martin

 --
 name: Martin Albrecht
 _pgp: http://pgp.mit.edu:11371/pks/lookup?op=getsearch=0x8EF0DC99
 _otr: 47F43D1A 5D68C36F 468BAEBA 640E8856 D7951CCF
 _www: http://martinralbrecht.wordpress.com/
 _jab: martinralbre...@jabber.ccc.de

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[sage-support] solving Diophantine equations in Sage

2012-12-08 Thread Robert Dodier
Hello, is there a way to solve Diophantine equations in Sage? If not a
general method, perhaps at least some special cases.

There is some interest in solving such equations in Maxima -- I am
daydreaming about porting whatever implementation Sage has. Is there a
generally-accepted more-or-less best method these days? (Whether it is
implemented in Sage or not.)

There is this web page, http://www.alpertron.com.ar/METHODS.HTM, which
describes a method, and this one, http://www.alpertron.com.ar/JQUAD.HTM,
which has a calculator. Would anyone care to comment on the suitability
of either one as the basis for an implementation? Pointers to any other
resources would be interesting.

best

Robert Dodier

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Re: [sage-support] solving Diophantine equations in Sage

2012-12-08 Thread Christophe BAL
Hello.

There is no general method : see this page

http://mathworld.wolfram.com/DiophantineEquation.html


Best regards.
C.


2012/12/8 Robert Dodier robert.dod...@gmail.com

 Hello, is there a way to solve Diophantine equations in Sage? If not a
 general method, perhaps at least some special cases.

 There is some interest in solving such equations in Maxima -- I am
 daydreaming about porting whatever implementation Sage has. Is there a
 generally-accepted more-or-less best method these days? (Whether it is
 implemented in Sage or not.)

 There is this web page, http://www.alpertron.com.ar/METHODS.HTM, which
 describes a method, and this one, http://www.alpertron.com.ar/JQUAD.HTM,
 which has a calculator. Would anyone care to comment on the suitability
 of either one as the basis for an implementation? Pointers to any other
 resources would be interesting.

 best

 Robert Dodier

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Re: [sage-support] Re: Solve system of non linear equations

2012-12-08 Thread john_perry_usm
On Saturday, December 8, 2012 11:07:31 AM UTC-6, Santanu wrote:

 Thank you. But when I try to solve
 f1=x1 + x2 + x4 + x10 + x31 + x43 + x56 , 
 f2=x2 + x3 + x5 + x11 + x32 +x44 + x57,

 it becomes very slow. Is there any faster approach like 
 F4 algorithm available in Sage? 


F4 is not yet available in Sage; as far as I know, we're waiting for 
upstream (Singular) to implement it. They've been working on it very hard 
for quite some time, because they're trying to do it right, and it's not as 
easy as one might think. Last I heard, they had both F4 and an F5-like 
algorithm with respectable performance in an internal development branch, 
but they had to integrate it with the regular Singular branch. It's been a 
huge effort to do this, since memory management  other tricky issues come 
into play.

Daniel Cabarcas wrote an open-source implementation of F4 for his Master's 
Thesis, which you might be able to find online. Bjarke Roune  Michael 
Stillman described an open-source F5-like algorithm at ISSAC 2012, and gave 
an address where you can download it in the paper.

All that said, when I look at your system, I wonder if something's wrong 
with the formatting, because it looks to me as if it's either linear or 
univariate. Is that the case?

regards
john perry

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[sage-support] Re: solving Diophantine equations in Sage

2012-12-08 Thread Volker Braun
Solving a linear diophantine equation is an application of the Smith form.

A quadratic diophantine equation can be solved with the Hasse-Minkowski 
theorem, though thats is definitely more advanced 
(http://en.wikipedia.org/wiki/Hasse%E2%80%93Minkowski_theorem)

If its not one of these cases then you are pretty much out of luck ;-)

On Saturday, December 8, 2012 5:46:00 PM UTC, Robert Dodier wrote:

 Hello, is there a way to solve Diophantine equations in Sage?


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[sage-support] Re: solving Diophantine equations in Sage

2012-12-08 Thread Robert Dodier
On 2012-12-08, Volker Braun vbraun.n...@gmail.com wrote:

 Solving a linear diophantine equation is an application of the Smith form.

 A quadratic diophantine equation can be solved with the Hasse-Minkowski 
 theorem, though thats is definitely more advanced 

Thanks for the info. Are there implementations of these approaches in
Sage or any upstream project? (e.g. PARI/GP, Singular, I don't know.)

best,

Robert Dodier

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Re: Re: [sage-support] Re: Solve system of non linear equations

2012-12-08 Thread Martin Albrecht
We are talking about the Boolean polynomial ring here, right? So an F4 style 
algorithm is used by default (subject to some heuristics). To emphasise you'd 
have to construct your ring using the BooleanPolynomialRing constructor.

On Saturday 08 Dec 2012, john_perry_usm wrote:
 On Saturday, December 8, 2012 11:07:31 AM UTC-6, Santanu wrote:
  Thank you. But when I try to solve
  f1=x1 + x2 + x4 + x10 + x31 + x43 + x56 ,
  f2=x2 + x3 + x5 + x11 + x32 +x44 + x57,
  
  it becomes very slow. Is there any faster approach like
  F4 algorithm available in Sage?
 
 F4 is not yet available in Sage; as far as I know, we're waiting for
 upstream (Singular) to implement it. They've been working on it very hard
 for quite some time, because they're trying to do it right, and it's not as
 easy as one might think. Last I heard, they had both F4 and an F5-like
 algorithm with respectable performance in an internal development branch,
 but they had to integrate it with the regular Singular branch. It's been a
 huge effort to do this, since memory management  other tricky issues come
 into play.
 
 Daniel Cabarcas wrote an open-source implementation of F4 for his Master's
 Thesis, which you might be able to find online. Bjarke Roune  Michael
 Stillman described an open-source F5-like algorithm at ISSAC 2012, and gave
 an address where you can download it in the paper.
 
 All that said, when I look at your system, I wonder if something's wrong
 with the formatting, because it looks to me as if it's either linear or
 univariate. Is that the case?
 
 regards
 john perry

Cheers,
Martin

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_otr: 47F43D1A 5D68C36F 468BAEBA 640E8856 D7951CCF
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Re: [sage-support] Re: solving Diophantine equations in Sage

2012-12-08 Thread Ivan Andrus
On Dec 8, 2012, at 7:27 PM, Volker Braun vbraun.n...@gmail.com wrote:

 Solving a linear diophantine equation is an application of the Smith form.
 
 A quadratic diophantine equation can be solved with the Hasse-Minkowski 
 theorem, though thats is definitely more advanced 
 (http://en.wikipedia.org/wiki/Hasse%E2%80%93Minkowski_theorem)
 
 If its not one of these cases then you are pretty much out of luck ;-)

I know basically nothing about Diophantine equations, but they have come up in 
my research a few times.  Is there some sort of database of which equations 
have been solved (or not).  I'm thinking something along the lines of the OEIS 
that would allow you to search for an equation to find out what could be said 
about it.  I couldn't find any such thing on google, but it seems nearly 
inconceivable to me that such a thing wouldn't exist.  Or are number theorists 
just born knowing this stuff.  :-)

-Ivan

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Re: [sage-support] Re: solving Diophantine equations in Sage

2012-12-08 Thread Volker Braun
On Saturday, December 8, 2012 7:03:48 PM UTC, Ivan Andrus wrote:

 Or are number theorists just born knowing this stuff.  :-) 


Beats me, I'm just a physicist dabbling in computer programming ;-) 

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Re: [sage-support] Re: solving Diophantine equations in Sage

2012-12-08 Thread William Stein
On Dec 8, 2012 10:27 AM, Volker Braun vbraun.n...@gmail.com wrote:

 Solving a linear diophantine equation is an application of the Smith form.

 A quadratic diophantine equation can be solved with the Hasse-Minkowski
theorem, though thats is definitely more advanced (
http://en.wikipedia.org/wiki/Hasse%E2%80%93Minkowski_theorem)

 If its not one of these cases then you are pretty much out of luck ;-)



Elliptic curves (cubic plane curves) are another major case with a
developed theory.

This stuff basically *is* number theory...  and as such, Sage and Magma are
pretty powerful for this, far ahead of anything else...

 On Saturday, December 8, 2012 5:46:00 PM UTC, Robert Dodier wrote:

 Hello, is there a way to solve Diophantine equations in Sage?

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Re: [sage-support] solving Diophantine equations in Sage

2012-12-08 Thread Georgi Guninski
On Sat, Dec 08, 2012 at 05:46:00PM +, Robert Dodier wrote:
 Hello, is there a way to solve Diophantine equations in Sage? If not a
 general method, perhaps at least some special cases.
 
 There is some interest in solving such equations in Maxima -- I am
 daydreaming about porting whatever implementation Sage has. Is there a
 generally-accepted more-or-less best method these days? (Whether it is
 implemented in Sage or not.)
 
 There is this web page, http://www.alpertron.com.ar/METHODS.HTM, which
 describes a method, and this one, http://www.alpertron.com.ar/JQUAD.HTM,
 which has a calculator. Would anyone care to comment on the suitability
 of either one as the basis for an implementation? Pointers to any other
 resources would be interesting.
 
 best
 
 Robert Dodier



pari/gp which is included in sage can solve the special case
of Thue equations.

In pari console:
th=thueinit(x^5-2,1);\\x^5-2*y^5, ,1 is for unconditional result
t=thue(th,65)\\x^5-2*y^5=65
%7 = [[1, -2]]


If you want to work from sage the above example is:
sage: AA.x=QQ[]
sage: th=gp.thueinit(x^5-2,1)
sage: gp.thue(th,65)
[[1, -2]]

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Re: [sage-support] Solve system of non linear equations

2012-12-08 Thread Georgi Guninski
On Sat, Dec 08, 2012 at 11:44:19AM +0530, Santanu Sarkar wrote:
 Dear all,
   I have a system of non linear equations over GF(2). How to solve
 them in Sage?


If you need to solve large nonlinear systems over GF(2) and don't
insist on using sage I suspect a better choice is to convert
them to conjunctive normal form (CNF) and then use state of the
art SAT solver like lingeling/cryptominisat.

There are sage programs for converting ANF to CNF, don't know if
they are in vanilla sage.

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