I've uploaded a new version of my positional derivative package
(pdiff.lisp) to
http://www.unk.edu/acad/math/people/willisb/home.html
(To download pdiff.lisp using netscape, right click on the file and
choose "Save Link As"; I don't know how to do this with other
browsers -- try downloading pdiff-1.3.0.tar.gz instead.)
View pdf documentation here
http://www.unk.edu/acad/math/people/willisb/pdiff-doc.pdf
Briefly, pdiff allows Maxima to evaluate derivatives of unknown functions
without using gradef. An example:
(C1) load("e:/pdiff.lisp")$
Loading e:/pdiff.lisp
Finished loading e:/pdiff.lisp
(C2) de : 'diff(f,x,2) + 'diff(f,y,2)$
(C3) de, f : p(x - %i*y) + q(x + %i*y), diff, ratsimp;
(D3) 0
(C4) diff(f(x,x^2),x);
2 2
(D4) f (x, x ) + 2 x f (x, x )
(1, 0) (0, 1)
(C5)
The new version adds some options for tex-ing expressions, fixes
some bugs, and adds some new features to the first version.
I'll appreciate all suggestions and (especially) bug reports.
Regards,
Barton