MAXIMA - ALGSYS



Keith Needham wrote:
> The ALGSYS command accepts inputs (and generates outputs) exactly of the 
> type I need, but I would like to know how it does this!
> 
> Where may I see the source code for this one function?

src/algsys.lisp.

You'll need to know Lisp and maxima internals to understand how this 
works.  But this comment in the file might be helpful:

;;It solves systems of polynomial equations by straight-forward
;;resultant hackery.  Other possible methods seem worse:
;;the Buchberger-Spear canonical ideal basis algorithm is slow,
;;and the "resolvent" method (see van der Waerden, section 79)
;;blows up in time and space.  The "resultant"
;;method (see the following sections of van der Waerden and
;;Macaulay's book - Algebraic Theory of Modular Systems) looks
;;good, but it requires the evaluation of large determinants.
;;Unless some hack (such as prs's for evaluating resultants of
;;two polynomials) is developed for multi-polynomial resultants,
;;this method will remain impractical.

;;Some other possible ideas:  Keeping the total number of equations 
constant,
;;in an effort to reduce extraneous solutions, or Reducing to a linear
;;equation before taking resultants.

Ray