[Maxima] MAXIMA - ALGSYS
Raymond Toy (RT/EUS)
raymond.toy at ericsson.com
Fri Aug 24 08:08:03 CDT 2007
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?
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
;;in an effort to reduce extraneous solutions, or Reducing to a linear
;;equation before taking resultants.
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