#1123 solve/algsys bug

closed
nobody
5
2009-01-25
2007-02-19
No

sys:[b2 + a1 = r2, a1 * b2 = r3, a2 * b2 + a3 * b1 = r4, a3 * b2 + a5 + r4 = d5, a5 * b1 = 0];
solve(sys, [a1, a2, a3, a5, r2, r3, r4, b1, b2]);

result in

Maxima encountered a Lisp error:

Error in MACSYMA-TOP-LEVEL [or a callee]: 0 is not of type LIST.

Reported by Laurent Couraud

Discussion

  • Barton Willis
    Barton Willis
    2007-02-19

    Logged In: YES
    user_id=895922
    Originator: NO

    With algebraic : true, we get a different error:

    (%i7) solve(sys, [a1, a2, a3, a5, r2, r3, r4, b1, b2]), algebraic : true;
    `algsys' cannot solve - system too complicated. -- an error. To debug this try debugmode(true);

     
  • Robert Dodier
    Robert Dodier
    2007-03-03

    • labels: --> Lisp Core - Solving equations
     
  • Dieter Kaiser
    Dieter Kaiser
    2009-01-25

    • status: open --> closed
     
  • Dieter Kaiser
    Dieter Kaiser
    2009-01-25

    This bug reported is related to the bug report SF[609466].

    A test for a number zero in a call to punivarp has been checked in.
    Maxima no longer gets a fatal Lisp error for the example given in this
    bug report, but returns an error message:

    `algsys' cannot solve - system too complicated.
    -- an error. To debug this try debugmode(true);

    Closing this bug report as fixed, because Maxima no longer gets a Lisp Error.

    See the discussion in SF[1430379] for a suggestion to improve algsys by setting the flag $algebraic to TRUE.

    Dieter Kaiser