#196 solve cannot handle sets of non-linear e

[Anonymous]

intech19:/fix/f/debian/mm/maxima/59/maxima$ ./maxima-local
GCL (GNU Common Lisp) Version(2.5.0) Thu Dec 5
08:07:35 EST 2002
Licensed under GNU Library General Public License
Contains Enhancements by W. Schelter
Maxima 5.9.0rc3 http://maxima.sourceforge.net
Distributed under the GNU Public License. See the file
COPYING.
Dedicated to the memory of William Schelter.
This is a development version of Maxima. The function
bug_report()
provides bug reporting information.
(C1) y:[ (x2-x1)^2+(y2-y1)^2=36^2,
(x3-x1)^2+(y3-y1)^2=25^2, (x3-x2)^2+(y3-y2)^2
=17^2];

       2        2              2        2

(D1) [(Y2 - Y1) + (x2 - x1) = 1296, (Y3 - Y1) + (x3
- x1) = 625,

                          2        2
                     \(Y3 - Y2\)  + \(x3 - x2\)  = 289\]

(C2) solve(y, [x1, y1, x2, y2, x3, y3]);

Error: 0 is not of type LIST.
Fast links are on: do (si::use-fast-links nil) for
debugging
Error signalled by MACSYMA-TOP-LEVEL.
Broken at MACSYMA-TOP-LEVEL. Type :H for Help.
=======================================================================
intech19:/fix/f/debian/mm/maxima/59/maxima$ ./maxima-local
i i i i i i i ooooo o ooooooo ooooo
ooooo
I I I I I I I 8 8 8 8 8
o 8 8
I \ `+' / I 8 8 8 8
8 8
\ `-+-' / 8 8 8 ooooo
8oooo
`-__|__-' 8 8 8 8 8
| 8 o 8 8 o 8 8
------+------ ooooo 8oooooo ooo8ooo ooooo 8

Copyright (c) Bruno Haible, Michael Stoll 1992, 1993
Copyright (c) Bruno Haible, Marcus Daniels 1994-1997
Copyright (c) Bruno Haible, Pierpaolo Bernardi, Sam
Steingold 1998
Copyright (c) Bruno Haible, Sam Steingold 1999-2001

Maxima 5.9.0rc3 http://maxima.sourceforge.net
Distributed under the GNU Public License. See the file
COPYING.
Dedicated to the memory of William Schelter.
This is a development version of Maxima. The function
bug_report()
provides bug reporting information.
(C1) y:[ (x2-x1)^2+(y2-y1)^2=36^2,
(x3-x1)^2+(y3-y1)^2=25^2, (x3-x2)^2+(y3-y2)^2
=17^2];
2 2 2 2
(D1) [(Y2 - Y1) + (x2 - x1) = 1296, (Y3 - Y1) + (x3
- x1) = 625,

                          2        2
                     \(Y3 - Y2\)  + \(x3 - x2\)  = 289\]

(C2) solve(y, [x1, y1, x2, y2, x3, y3]);

*** - CDR: 0 is not a list
The following restarts are available:
R1 = Macsyma top-level

1. Break [1]>

[Stavros Macrakis]

Logged In: YES
user_id=588346

Another example (checked in 5.9.0rc4):

algsys([a*b*C-(a-1)*(a+1)*d,-b*(a*d-b*C+1),-C*(a*d-b*C+1),a-d*
(a*d-b*C)],[a,b,c,d])
=>

Error: 0 is not of type LIST.

[Robert Dodier]

Logged In: YES
user_id=501686

Still present in 5.9.3cvs.

2nd example needs to have c replaced by C to trigger error:

algsys ([a*b*C-(a-1)*(a+1)*d,-b*(a*d-b*C+1),
-C*(a*d-b*C+1),a-d*(a*d-b*C)], [a,b,C,d]);
=> error

[Barton Willis]

Logged In: YES
user_id=895922

I think the error happens when the function 'punivarp'
receives 0 as its argument. I don't know what punivarp is
supposed to do. And maybe something went wrong long before
(punivarp 0).

[Dieter Kaiser]

This bug report is related to SF[609466] "Fatal error in solve/algsys" and SF[1663399] "solve/algsys bug".

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. Algsys is not able to solve the example in this bug report.

Maxima does not get more solutions with this fix. See the discussion in SF[1430379] for a suggestion to improve algsys by setting the flag $algebraic to TRUE.

Dieter Kaiser