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Article #85Re: reading large polynomials
From: Richard Fateman
Date: Wed, 04 Mar 1992 18:51
Date: Wed, 04 Mar 1992 18:51
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2116 bytes
The correct way to expand polynomials in macsyma is to use rat( ), not expand( ). The latter command is far more general and is probably not comparable to commands of the same name in other systems. This lack of comparability is unfortunate and has lead to lots of bogus comparisons of speed. There is also an issue of data representation -- the right way to represent polynomials (especially large ones) in Macsyma is to use the rational function "CRE" form. Since REDUCE's principal (only?) representation is more like CRE form, that would be the more logical comparison. In any case, I tried the computation of rat(p^6) on a version of macsyma (not the official symbolics version but a DOE version) (on a MIPS M/120 computer) and it took 86.45 CPU seconds. This used Allegro common lisp. Another version took 69 seconds -- an HP 9000/720 workstation in AKCL. Exact times would vary depending on debugging / optimization switches in compilers etc. But it is not 172+ minutes if done right. There are ways of reordering the polynomial variables by the ordergreat command in macsyma, (or ratvars, within the rational function system), but I don't know offhand of a built-in way of seeing the results in (say) total-degree-order. This could be programmed of course (and most likely already has been programmed, internally, for Grobner basis computations). Richard Fateman
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X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 12b417,89715a99287d43bc X-Google-Attributes: gid12b417,public X-Google-ArrivalTime: 1992-03-04 22:09:37 PST Path: arc1-ca.pugleaf.net!sparky!uunet!sun-barr!ccut!hearn@rand.org From: fateman@peoplesparc.berkeley.edu (Richard Fateman) Newsgroups: fj.mail-lists.reduce Subject: Re: reading large polynomials Message-ID: <9203041851.AA29268@hilbert.rand.org> Date: 4 Mar 92 18:51:37 GMT Sender: hearn@rand.org Distribution: fj Lines: 26 Approved: fj.mail-lists.reduce@ccut.cc.u-tokyo.ac.jp Return-Path: <hearn@rand.org> Original-To: monagan@inf.ethz.ch, reduce-forum@rand.org Original-Cc: fateman@peoplesparc.berkeley.edu, jpg@allegheny.scrc.symbolics.com