[GiNaC-list] Randomness when using lsolve

[Federico Bergero]

Hello everybody I'm new to GiNaC.

I'm trying to use it to solve linear algebraic system of equations and
running the example from the tutorial
https://www.ginac.de/tutorial/Solving-linear-systems-of-equations.html#Solving-linear-systems-of-equations

 symbol a("a"), b("b"), x("x"), y("y");
         lst eqns, vars;
         eqns = a*x+b*y==3, x-y==b;
         vars = x, y;
         cout << lsolve(eqns, vars) << endl;

While it works perfectly when I run it several times I get different
solutions (they are all equivalent though). For example:
{x==(3+b^2)*(a+b)^(-1),y==-(a+b)^(-1)*(-3+a*b)}
or
{x==(b+a)^(-1)*(3+b^2),y==-(-3+b*a)*(b+a)^(-1)}

what is going on there? Is there a way to have a deterministic solution?

Thanks in advance.
Fede

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