> -----Original Message-----
> From: Rogers, Raymond [mailto:raymond-rogers at idexx.com]
> > -----Original Message-----
> > From: Robert Dodier [mailto:robert.dodier at gmail.com]
> > We might want to try to get to the bottom of this. I'm guessing that
> > the problem is ratsimp or factor or something which is not supposed
> > to take too long. I suspect that the problem is not in the
> computation
> > itself but in simplification of partial results or something
> > like that.
>
> Works treated as a matrice:
>
> ss:matrix([1,x1,y1,x1^2,y1^2,x1*y1],[1,x2,y2,x2^2,y2^2,x2*y2],
> [1,x3,y3,x3^2,
> y3^2,
> x3*y3],[1,x4,y4,x4^2,y4^2,x4*y4],[1,x5,y5,x5^2,y5^2,x5*y5],[1,
> x6,y6,x6^2,
> y6^2,x6*y6])
> ;
>
> Invert(ss);
> Answer omitted for the sake those with limited attention spans (me).
>
Perhaps I should explain; taking the differential and stuffing a matrix is a
general method of resolving linear problems. It's crude but my version of
Maxima "time(o)" command gives an answer of 0.16 seconds.
RR