gflineq

Find particular solution of Ax = b over a prime Galois field

Syntax

x = gflineq(A,b,p)
[x,vld] = gflineq(...)

Description

x = gflineq(A,b,p) returns a particular solution of the linear equation A x = b over GF(p), where p is a prime number. If A is a k-by-n matrix and b is a vector of length k, then x is a vector of length n. Each entry of A, x, and b is an integer between 0 and p-1. If no solution exists, then x is empty.

[x,vld] = gflineq(...) returns a flag vld that indicates the existence of a solution. If vld = 1, then the solution x exists and is valid; if vld = 0, then no solution exists.

Examples

The code below produces some valid solutions of a linear equation over GF(3).

A = [2 0 1;
     1 1 0;
     1 1 2];
% An example in which the solutions are valid
[x,vld] = gflineq(A,[1;0;0],3)

The output is below.

x =

     2
     1
     0


vld =

     1

By contrast, the command below finds that the linear equation has no solutions.

[x2,vld2] = gflineq(zeros(3,3),[2;0;0],3)

The output is below.

This linear equation has no solution.

x2 =

     []


vld2 =

     0

Algorithm

gflineq uses Gaussian elimination.

See Also

gfadd, gfdiv, gfroots, gfrank, gfconv, conv, Galois Fields of Odd Characteristic


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