1. Load vect.mc from the share directory; vector.mc in the share2
directory is broken.
2. In vect.mc, I had to change the two define_variable statements from
DEFINE_VARIABLE(sfprod,1,any)$
DEFINE_VARIABLE(sf,[1,1,1],list)$
to
DEFINE_VARIABLE(SFPROD,1,any)$
DEFINE_VARIABLE(SF,[1,1,1],list)$
(I don't understand why SF and SFPROD must be uppercase here; with my
maxima, they do need to be.)
3. Try the following:
(C1) load("vect.mc");
Warning - you are redefining the MACSYMA function TRIGSIMP
Warning - you are redefining the MACSYMA function IMPROVE
Warning - you are redefining the MACSYMA function UPDATE
(D1) vect.mc
/* By default, the coordinate system is cartesian with coordinates
X,Y, and Z (upper case, not lower case) */
(C2) grad(X^2 + Y^2);
2 2
(D2) GRAD (Y + X )
(C3) express(%);
d 2 2 d 2 2 d 2 2
(D3) [-- (Y + X ), -- (Y + X ), -- (Y + X )]
dX dY dZ
(C4) ev(%,diff);
(D4) [2 X, 2 Y, 0]
(C5)
4. There is some documentation in vect.usg; compared to the rest of maxima, the
vector code isn't as well tested. I'd be careful about trusting it for much more
than homework.
blw