A workaround is to apply the grobner method and set algexact to true:
(%i1) load(to_poly_solve)$
Loading maxima-grobner $Revision: 1.6 $ $Date: 2009-06-02 07:49:49 $
(%i2) eqs : [b^4+6*a^2*b^2+a^4,4*a*b^3+4*a^3*b-1]$
(%i3) %solve(eqs,[a,b],'use_grobner=true),algexact : true;
(%o3) %union([a=-(sqrt(2)*%i-sqrt(2)-2)/4,b=%i/2^(3/2)-1/2^(3/2)+1/2], <junk deleted>
Check the solution
(%i4) map(lambda([s],ratsimp(subst(s,eqs))), %);
(%o4) %union([0,0])
Each solution checks. When algexact is true, algsys says the solution set is empty
(%i1) algsys([b^4+6*a^2*b^2+a^4,4*a*b^3+4*a^3*b-1],[a,b]),algexact : true;
(%o1) []
Additionally setting algebraic to true yields and error
(%i2) algsys([b^4+6*a^2*b^2+a^4,4*a*b^3+4*a^3*b-1],[a,b]),algexact : true,algebraic : true;
Polynomial quotient is not exact
And that would be a bug.
--Barton
________________________________________
From: maxima-bounces at math.utexas.edu [maxima-bounces at math.utexas.edu] on behalf of andre maute [andre.maute at gmx.de]
Sent: Wednesday, February 06, 2013 19:42
To: maxima at math.utexas.edu
Subject: Increasing the precision of algsys
Hi list,
has somebody an idea, how to increase the precision of algsys?
fpprec : 30
doesn't work.
use e.g.
algsys([b^4+6*a^2*b^2+a^4,4*a*b^3+4*a^3*b-1],[a,b]);
which gives approximate solutions.
Increasing the number of significant digits may help
with the inverse symbolic calculator.
Regards
Andre
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