Am Samstag, den 03.07.2010, 12:48 -0700 schrieb Paul Bowyer:
> I don't claim to know the reason for it, but when I tried this in
> Maxima-5-20.1, I got similar results until I removed the
> "load("vect");" line. After that all worked as expected.
>
> Paul
>
> On 07/03/2010 07:15 AM, Takahashi Hideo2 wrote:
> > Hi,
> >
> > I am trying to do a simple matrix dot vector calculation and getting
> > an error.
> >
> > My case boils down to this :
> >
> > (%i1) load("vect");
> > (%o1) /usr/local/share/maxima/5.20.1/share/vector/vect.mac
> > (%i2) load("eigen");
> > (%o2) /usr/local/share/maxima/5.20.1/share/matrix/eigen.mac
> > (%i4) ident(2);
> > (%o4) matrix([1,0],[0,1])
> > (%i5) columnvector([0,0]);
> > (%o5) matrix([0],[0])
> > (%i6) ident(2) . columnvector([0,0]);
> > MULTIPLYMATRICES: attempt to multiply nonconformable matrices.
> > -- an error. To debug this try: debugmode(true);
> >
> > What am I doing wrong?
> >
> > Without the libraries, I get this, as I expect:
> >
> > (%i1) m:matrix([1,0],[0,1]);
> > (%o1) matrix([1,0],[0,1])
> > (%i2) v:matrix([0],[0]);
> > (%o2) matrix([0],[0])
> > (%i3) m.v;
> > (%o3) matrix([0],[0])
> > --
> > --
> > Hideo at Yokohama - hideo dot at dot yokohama
> > atsign gmail dot com
The package vect has declared the "." operator to be commutative. This
was a known bug, which has been fixed some time ago.
So we do not have the problem in the current CVS version of Maxima. In
the next release of Maxima 1.22 the problem should be no longer present.
Dieter Kaiser