June 2011 - GiNaC-devel

series() errors with divide by zero
by J Sage 27 Jun '11

27 Jun '11

Hi, There is an error in ginac when taking a series of a function at a singular point, for instance in ginsh, > series(sqrt(x),x,3); power::eval(): division by zero from ginac-1.6 file power.cpp line 408. I instrumented power.cpp with some printf functions and found the offending dispatch to be in line 665: coeff = deriv.subs(r, subs_options::no_pattern); while evaluating the third term in the expansion, presumably with a 1/x factor. I'm new to ginac so its taking me a while to learn the code -- next step is to try and get it running in gdb -- so I'd appreciate any input from the list about how ginac is handling and/or is supposed to handle this kind of error. Other software, like maxima, handles the problem fine: (%o6) maxima(sqrt(x), x, 0, 3) (%i7) taylor(sqrt(x),x,0,3); Thanks in advance, John * *

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-358-g29b8244
by git＠ginac.de 23 Jun '11

23 Jun '11

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 29b8244d6141ecb6f8d90480ade69af407270441 (commit) from 7a7b485ed57429bb21e7591f4a1b0454dd1f4aae (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 29b8244d6141ecb6f8d90480ade69af407270441 Author: Vladimir V. Kisil <kisilv(a)maths.leeds.ac.uk> Date: Thu Jun 23 16:20:59 2011 +0200 Be more careful before converting to indexed. This patch makes GiNaC pass it's test suite when compiled with -DDO_GINAC_ASSERT. ----------------------------------------------------------------------- Summary of changes: check/exam_clifford.cpp | 3 ++- ginac/clifford.cpp | 12 +++++++----- 2 files changed, 9 insertions(+), 6 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-357-g7a7b485
by git＠ginac.de 21 Jun '11

21 Jun '11

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 7a7b485ed57429bb21e7591f4a1b0454dd1f4aae (commit) from 77c2acd59e345fe7697304a865a8f41d43494129 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 7a7b485ed57429bb21e7591f4a1b0454dd1f4aae Author: Jens Vollinga <jens.vollinga(a)googlemail.com> Date: Tue Jun 21 21:36:16 2011 +0200 Made yyerror() string argument constant to avoid an compile error with gcc 4.6. ----------------------------------------------------------------------- Summary of changes: ginsh/ginsh.h | 2 +- ginsh/ginsh_parser.yy | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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Re: [GiNaC-devel] indexes of clifford objects
by Vladimir V. Kisil 20 Jun '11

20 Jun '11

Dear Richard, >>>>> On Sun, 12 Jun 2011 12:13:30 +0200, "Richard B. Kreckel" <kreckel(a)ginac.de> said: RK> Sadly, it turns out that clifford_check6 triggers yet another RK> assertion, this time in clifford.cpp:1249. I am attaching the patch. In two places a conversion to indexed shall be preceded by a corresponding check. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://www.maths.leeds.ac.uk/~kisilv/

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-356-g77c2acd
by git＠ginac.de 12 Jun '11

12 Jun '11

This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GiNaC -- a C++ library for symbolic computations". The branch, master has been updated via 77c2acd59e345fe7697304a865a8f41d43494129 (commit) from 761a6d99032dbbd82e8166036c17b498edfaa058 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- commit 77c2acd59e345fe7697304a865a8f41d43494129 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Sun Jun 12 23:10:07 2011 +0200 Relax assertion in clifford ctor. Class clifford can be constructed with an idx object, now, not just with a varidx. ----------------------------------------------------------------------- Summary of changes: ginac/clifford.cpp | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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indexes of clifford objects
by Richard B. Kreckel 12 Jun '11

12 Jun '11

Hi! When compiling GiNaC with -DDO_GINAC_ASSERT, exam_clifford.cpp fails the test suite because clifford.cpp:105, assertion `is_a<varidx>(mu)' is violated. The function clifford_moebius_map constructs a clifford unit with an idx, not a varidx, if G is a matrix. The code in question was written by Vladimir in 2006. From a physicists point of view, I thought that it doesn't make sense to construct a clifford object with an idx instead of a varidx. But then, what's clifford_moebius_map doing? On the other hand, I also noticed that the tutorial does include examples of clifford objects with idx indices in section "A generic Clifford algebra". Strange. If someone with more insight could shed a light on this I could finish my recent quest to make GiNaC pass its test suite even when compiled with -DDO_GINAC_ASSERT. That would be great. Cheers -richy. -- Richard B. Kreckel <http://www.ginac.de/~kreckel/>

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Re: [GiNaC-devel] indexes of clifford objects
by Vladimir V. Kisil 10 Jun '11

10 Jun '11

Dear Richard, >>>>> On Mon, 06 Jun 2011 08:24:16 +0200, "Richard B. Kreckel" < kreckel(a)ginac.de> said: RK> and to the tutorial. Either way, can you recommend a patch? I am attaching the patch, which admits only varidx as valid parameters. I Hope I did everything right. Best wishes, Vladimir -- Vladimir V. Kisil email: kisilv(a)maths.leeds.ac.uk -- www: http://www.maths.leeds.ac.uk/~kisilv/

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