#1369 algsys hangs

open
nobody
5
2008-06-21
2008-03-13
Anonymous
No

algsys hangs on the following input:

eq1 : a*x + c*y + d*y^2/2 = 0;
eq2 : b*x + e*x^2 + f*y - g*y^3 = h;
algsys([eq1,eq2],[x,y]);

System information:

Maxima version: 5.12.0
Maxima build date: 15:52 7/20/2007
host type: i686-pc-linux-gnu
lisp-implementation-type: GNU Common Lisp (GCL)
lisp-implementation-version: GCL 2.6.7

Discussion

  • Barton Willis
    Barton Willis
    2008-03-14

    Logged In: YES
    user_id=895922
    Originator: NO

    A workaround is to eliminate x and solve the quartic for y; something like

    (%i14) eliminate([eq1,eq2],[x]);
    (%o14) [d^2*e*y^4+(4*c*d*e-4*a^2*g)*y^3+(4*c^2*e-2*a*b*d)*y^2+(4*a^2*f-4*a*b*c)*y-4*a^2*h]
    (%i15) solve(%,y)

    Of course, Maxima should not need any help.

     
  • Robert Dodier
    Robert Dodier
    2008-06-21

    • labels: 886274 --> Lisp Core - Solving equations