October 2002 - PURRS-devel - BUGSENG Mailman

purrs/src gosper.hh gosper.cc rr_solver.cc
by Tatiana Zolo 15 Oct '02

15 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-15 16:05:10 Modified files: src : gosper.hh gosper.cc rr_solver.cc Log message: Changed an argument from `int' to `Number'. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/gosper.hh.diff?cvsroot=… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/gosper.cc.diff?cvsroot=… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/rr_solver.cc.diff?cvsro…

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purrs/tests recurrences
by Alessandro Zaccagnini 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zaccagnini(a)cs.unipr.it 2002-10-14 19:04:33 Modified files: tests : recurrences Log message: Changed one solution (numerator and denominator were exchanged) and added more descriptive comments. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/tests/recurrences.diff?cvsr…

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purrs/src gosper.cc simplify.cc util.cc
by Tatiana Zolo 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-14 18:58:22 Modified files: src : gosper.cc simplify.cc util.cc Log message: Define NOISY only if not yet defined. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/gosper.cc.diff?cvsroot=… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/simplify.cc.diff?cvsroo… http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/util.cc.diff?cvsroot=pu…

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purrs/tests eqs_driver.cc
by Tatiana Zolo 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-14 18:51:53 Modified files: tests : eqs_driver.cc Log message: Accepts options so as to serve both as a debugging tool and as a test program for `make check'. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/tests/eqs_driver.cc.diff?cv…

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purrs/src alg_eq_solver.cc
by Tatiana Zolo 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-14 18:50:39 Modified files: src : alg_eq_solver.cc Log message: All prints are checked by the flags NOISY. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/alg_eq_solver.cc.diff?c…

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purrs/src rr_solver.cc
by Tatiana Zolo 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-14 18:49:38 Modified files: src : rr_solver.cc Log message: Implemented the function in order to solve first order recurrence relation with variable coefficients (for the moment it is commented). All prints are checked by the flag NOISY. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/rr_solver.cc.diff?cvsro…

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purrs/tests simplify_driver.cc
by Tatiana Zolo 14 Oct '02

14 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-14 14:23:13 Modified files: tests : simplify_driver.cc Log message: Improved. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/tests/simplify_driver.cc.di…

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[Fwd: Re: Now seriously: what is a polynomial?]
by Roberto Bagnara 13 Oct '02

13 Oct '02

-------- Original Message -------- Subject: Re: Now seriously: what is a polynomial? Date: Sun, 13 Oct 2002 14:07:57 +0200 (CEST) From: Richard B. Kreckel <kreckel(a)zino.physik.uni-mainz.de> Reply-To: ginac-list(a)zino.physik.uni-mainz.de To: <ginac-list(a)zino.physik.uni-mainz.de> On Wed, 9 Oct 2002, Christian Bauer wrote: [...] > > e = sqrt(2)*x > > e.info(info_flags::polynomial) == false > > That's a case where the GiNaC definition of a polynomial clashes with the > "intuitive" one. info() should probably return 'true' here, because sqrt(2) > is clearly a number. But so is zeta(3), and I'm not sure how to handle > this in a way that is general enough. I don't see a difference between sqrt(2) and zeta(3) apart from the irrelevant fact that zeta(3) is transcendental while sqrt(2) is just irrational. The point here was that Z[x,y,z,...] and Q[x,y,z,...] ought to be classified as polynomials while more general fields are something different. This is so because as soon as you start nesting roots it is not at all obvious how to obtain a canonical form -- definitely "expanding" is not enough. For more general functions (like zeta(2*n+1)) it becomes even less obvious. I'm not entirely sure but methinks a valid definition would be this one: A polynomial is an object that has a unique canonical form such that given two such objects their equality is guaranteed to be unambigously determined using `expand' on both objects. I think this is what I was having in mind when I implemented info(info_flags::polynomial) long ago. Does this make sense? Regards -richy. -- Richard B. Kreckel <Richard.Kreckel(a)GiNaC.DE> <http://www.ginac.de/~kreckel/> -- Prof. Roberto Bagnara Computer Science Group Department of Mathematics, University of Parma, Italy http://www.cs.unipr.it/~bagnara/ mailto:bagnara@cs.unipr.it

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purrs/src alg_eq_solver.cc
by Tatiana Zolo 11 Oct '02

11 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-11 21:31:06 Modified files: src : alg_eq_solver.cc Log message: Increased FIND_DIVISORS_THRESHOLD because during the resolution of the recurrence x(n) = x(n-1) + (27^n)^(-1) * factorial(1+n)^(-1) * factorial(2+n)^(-1) * factorial(n)^(-1) * factorial(3*n) (see file recurrences) we call `find_divisors()' with 1331. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/src/alg_eq_solver.cc.diff?c…

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purrs/tests recurrences
by Tatiana Zolo 11 Oct '02

11 Oct '02

CVSROOT: /cvs/purrs Module name: purrs Changes by: zolo(a)cs.unipr.it 2002-10-11 21:24:52 Modified files: tests : recurrences Log message: Added some recurrence relations with the non-homogeneous term containing factorials that are solved successfully. Patches: http://www.cs.unipr.it/cgi-bin/cvsweb.cgi/purrs/tests/recurrences.diff?cvsr…

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