Re: [Maxima-discuss] ratsimp not working as expected

[Richard F. <fa...@be...>]

On 3/6/2014 6:37 PM, andre maute wrote:
> Hi list,
>
> here is my next one, consider the following test case,
> which I wasn't able to reduce more.
> If one comments the line marked trigger, the other ratsimp line chokes.
>
> Kind regards
> Andre
>
> --- ratsimp-bug1.max -------------------------
> display2d : false;
> d : 4;
> A : genmatrix(lambda([k,l],v[[k,l]]-v[[0,l]]),d,d);
> detA : factor(determinant(A));
> AinvT : transpose(invert(A));
> /* AinvT : ratsimp(AinvT); /* error trigger */ */
> zz : [0,-1,0,0];
> h1 : transpose(matrix(zz));
> h2 : AinvT.h1;
> h3 : sum(h2[m,1]^2,m,1,d)*detA^2;
> res : ratsimp(h3); /* chokes if trigger is commented */
> --- ratsimp-bug1.max -------------------------
>
> --- ratsimp-bug1.txt -------------------------
>
> ... lots of text ...
>
> (%i11) res:ratsimp(h3)
> Quotient by a polynomial of higher degree
>    -- an error. To debug this try: debugmode(true);
>
> --- ratsimp-bug1.txt -------------------------

It worked for me.
(%o24) ?%build_info("5.30.0","2013-06-01 21:29:43","i686-pc-mingw32",
                     "GNU Common Lisp (GCL)","GCL 2.6.8")

note that
gcd;
   has value spmod.

Sometimes changing that removes the mysterious bug .. Quotient ..etc.
try gcd:subres  perhaps.

also, use  $ instead of ;  to suppress the "lots of text"  if you don't 
want to see it.

RJF

>
> [user@localhost ~]$ maxima
> Maxima 5.31.3 http://maxima.sourceforge.net
> using Lisp SBCL 1.1.12-1.fc20
> Distributed under the GNU Public License. See the file COPYING.
> Dedicated to the memory of William Schelter.
> The function bug_report() provides bug reporting information.
> STYLE-WARNING: redefining MAXIMA::$FILE_TYPE in DEFUN
> (%i1) build_info();
> (%o1)
> Maxima version: "5.31.3"
> Maxima build date: "2014-03-01 11:47:49"
> Host type: "x86_64-unknown-linux-gnu"
> Lisp implementation type: "SBCL"
> Lisp implementation version: "1.1.12-1.fc20"
>
>
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