Difference between revisions of "ApCoCoA-1:CharP.XLSolve"

From ApCoCoAWiki
Line 18: Line 18:
  
 
<example>
 
<example>
Use R::=QQ[x,y,z];
+
Use Z/(2)[x[1..4]];
I:=Ideal(x-y^2,x^2+xy,y^3);
+
F:=[
GBasis(I);
+
    x[1]x[2] + x[2]x[3] + x[2]x[4] + x[3]x[4] + x[1] + x[3] + 1,  
[x^2 + xy, -y^2 + x, -xy]
+
    x[1]x[2] + x[1]x[3] + x[1]x[4] + x[3]x[4] + x[2] + x[3] + 1,  
-------------------------------
+
    x[1]x[2] + x[1]x[3] + x[2]x[3] + x[3]x[4] + x[1] + x[4] + 1,  
Use Z::=ZZ[x,y,z];
+
    x[1]x[3] + x[2]x[3] + x[1]x[4] + x[2]x[4] + 1
-- WARNING: Coeffs are not in a field
+
    ];
-- GBasis-related computations could fail to terminate or be wrong
+
 
 +
-- Then we compute the solution with
 +
CharP.XLSolve(F);
 +
 
 +
-- And we achieve the following information on the screen together with the solution at the end.
 +
----------------------------------------
  
 +
  The size of Matrix is:
 +
No. of Rows=4
 +
No. of Columns=11
 +
Appling Gaussian Elimination...
 +
-- CoCoAServer: computing Cpu Time = 0
 
-------------------------------
 
-------------------------------
I:=Ideal(x-y^2,x^2+xy,y^3);
+
Gaussian Elimination Completed.
CharP.GBasisF2(I);
+
The variables found till now, if any are:
-- WARNING: Coeffs are not in a field
+
[x[1], x[2], x[3], x[4]]
-- GBasis-related computations could fail to terminate or be wrong
+
The size of Matrix is:
 +
No. of Rows=16
 +
No. of Columns=15
 +
Appling Gaussian Elimination...
 
-- CoCoAServer: computing Cpu Time = 0
 
-- CoCoAServer: computing Cpu Time = 0
 
-------------------------------
 
-------------------------------
[y^2 + x, x^2, xy]
+
Gaussian Elimination Completed.
-------------------------------
+
The variables found till now, if any are:
 +
[0, 1, 0, 1]
 +
[0, 1, 0, 1]
 +
 
 
</example>
 
</example>
  

Revision as of 16:13, 6 December 2010

CharP.GBasisF2

Computing the unique F_2-rational zero of a given polynomial system over F_2.

Syntax

CharP.XLSolve(F:LIST):LIST

Description


This function computes the unique zero in F_2^n of a polynomial system over F_2 . It uses XL-Algorithm to find the unique zero. The XL-Algorithm is impelemented only to find a unique solution. If the given polynomial system has more than one zeros in F_2^n then this function does not find any zero. In this case a massage for non-uniqueness will be displayed to the screen after reaching the maximum degree bound.

Please note: The function(s) explained on this page is/are using the ApCoCoAServer. You will have to start the ApCoCoAServer in order to use it/them.


  • @param F A system of polynomial over F_2 having a unique zero in F_2^n.

  • @return The unique solution of the given system in F_2^n.

Example

Use Z/(2)[x[1..4]];
F:=[
    x[1]x[2] + x[2]x[3] + x[2]x[4] + x[3]x[4] + x[1] + x[3] + 1, 
    x[1]x[2] + x[1]x[3] + x[1]x[4] + x[3]x[4] + x[2] + x[3] + 1, 
    x[1]x[2] + x[1]x[3] + x[2]x[3] + x[3]x[4] + x[1] + x[4] + 1, 
    x[1]x[3] + x[2]x[3] + x[1]x[4] + x[2]x[4] + 1
    ];

-- Then we compute the solution with
CharP.XLSolve(F);

-- And we achieve the following information on the screen together with the solution at the end.
----------------------------------------

  The size of Matrix is:
		No. of Rows=4
		No. of Columns=11
Appling Gaussian Elimination...
-- CoCoAServer: computing Cpu Time = 0
-------------------------------
Gaussian Elimination Completed.
	The variables found till now, if any are:
	[x[1], x[2], x[3], x[4]]
	The size of Matrix is:
		No. of Rows=16
		No. of Columns=15
Appling Gaussian Elimination...
-- CoCoAServer: computing Cpu Time = 0
-------------------------------
Gaussian Elimination Completed.
	The variables found till now, if any are:
	[0, 1, 0, 1]
[0, 1, 0, 1]


See also

GBasis

Introduction to CoCoAServer

Introduction to Groebner Basis in CoCoA

CharP.GBasisF4

CharP.GBasisF8

CharP.GBasisF16

CharP.GBasisF32