Grobner



Raymond Toy (RT/EUS) wrote:
> Michel Talon wrote:
>> Raymond Toy (RT/EUS) wrote:
>>> I don't see any issues with current CVS with cmucl, but I haven't
>>> finished running the entire demo yet.  
>> In fact cmucl was not available on Ubuntu (precompiled) and doesn't
>> seem to work on FreeBSD-7 so i have only tried with sbcl. Hence it seems
>> that sbcl has a problem.
> 
> Was the failure early in the demo or late?

Found it.  It also fails with cmucl AND gcl with current CVS.  The issue 
appears to be that $ezgcd returns T, and the code wants to take the cdr 
of it.
There's only one place in grobner.lisp that does (cdr ($ezgcd x y)).

I don't know anything about the code or Grobner basis, so I'm at a loss.

In any case, this is the test in grobner.demo that causes the error:

poly_grobner([x^5+y^4+z^3-1,x^3+y^3+z^2-1], [x,y,z]), modulus=3;

Ray