July 2020 - GiNaC-devel

Re: [GiNaC-devel] Sqrfree_parfrac Issue GiNaC
by Vladimir V. Kisil 02 Aug '20

02 Aug '20

Dear Konstantin, Many thanks for reporting the bug with a detailed description. I am attaching a patch to fix it. Best wishes, Vladimir -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Maps https://doi.org/10.1142/p835 Soft: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter notebooks: https://github.com/vvkisil/MoebInv-notebooks ________________________________________ From: GiNaC-list <ginac-list-bounces(a)ginac.de> on behalf of Konstantin Leyde <konstantin.leyde(a)live.com> Sent: 22 July 2020 19:16 To: ginac-list(a)ginac.de Cc: vittorio del duca; Claude Duhr Subject: [GiNaC-list] Sqrfree_parfrac Issue GiNaC Hello, My name is Konstantin Leyde, and I am a master student in physics at the ETH Zurich. For my thesis project, I have been working with the GiNaC library, and I have encountered an issue with the partial fractioning (sqrfree_parfrac) routine: Unless I misunderstood the way the sqrfree_parfrac routine works, it appears that for special cases, the output of the sqrfree_parfrac routine misses a numerical prefactor for one term, and thus returns the wrong answer. Please find attached a pdf, that explains the problem in more detail. In this pdf (as well as separately) we have attached the code that shows the issue. Many thanks in advance, Best wishes, Konstantin

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-667-gc2ef6cb0
by Richard B. Kreckel 30 Jul '20

30 Jul '20

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 c2ef6cb074a85957bd684337552fe9d84451d307 (commit) from b773294dd380ae81056c3d37b647500aae738ea1 (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 c2ef6cb074a85957bd684337552fe9d84451d307 Author: Richard Kreckel <kreckel(a)ginac.de> Date: Thu Jul 30 00:20:22 2020 +0200 [BUGFIX] factor_multivariate(): respect unit... ...if the content of polynomial isn't a number and needs to be factored. And while at it, reduce the scope of a local variable. ----------------------------------------------------------------------- Summary of changes: ginac/factor.cpp | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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Power laws
by Vladimir V. Kisil 28 Jul '20

28 Jul '20

Dear All, I want to celebrate the 10th anniversary of this patch https://www.ginac.de/pipermail/ginac-devel/2009-October/001675.html by its re-submission. Since it was not objected since the original submission by anyone, it may be the time now to add this basic calculus-textbook rule to GiNaC. Best wishes, Vladimir -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Transformations http://goo.gl/EaG2Vu Software: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter (Colab): https://github.com/vvkisil/MoebInv-notebooks Jupyter (CodeOcean): https://codeocean.com/capsule/7952650/tree

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Re: [GiNaC-devel] [GiNaC-list] 回复: issue about series involving positive symbol
by Vladimir V. Kisil 28 Jul '20

28 Jul '20

Dear Feng, Thanks for reporting this (rather severe) issue. I am attaching a patch to fix it. It also includes additional GiNaC self-check. Best wishes, Vladimir PS. The previous not yet committed bugfix is attached as well. -- Vladimir V. Kisil http://www.maths.leeds.ac.uk/~kisilv/ Book: Geometry of Mobius Maps https://doi.org/10.1142/p835 Soft: Geometry of cycles http://moebinv.sourceforge.net/ Jupyter notebooks: https://github.com/vvkisil/MoebInv-notebooks ________________________________________ From: GiNaC-list <ginac-list-bounces(a)ginac.de> on behalf of Feng Feng <f.feng(a)outlook.com> Sent: 27 July 2020 02:23 To: ginac-list(a)ginac.de Subject: [GiNaC-list] 回复: issue about series involving positive symbol I got a more compact case for this issue, by changing the in1 and in2 to ex in1 = reader("t^2/(3*m^2-t*m^2)/2"); ex in2 = reader("-(m^(-2)*(-3+t)^(-1)*t^2/2)"); sometimes we get the output: in1-in2 = 0 diff = 0 while, for some other times, we get the output: in1-in2 = 0 diff = 96*log(1/48) it seems that the sign of the log term has been changed. Best regards! Feng

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[SCM] GiNaC -- a C++ library for symbolic computations branch, master, updated. release_1-4-0-666-gb773294d
by Richard B. Kreckel 27 Jul '20

27 Jul '20

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 b773294dd380ae81056c3d37b647500aae738ea1 (commit) via 1256fb73b64a1cdfb0838df06facbc1e8b2d5f83 (commit) from 8a7fb0be7ad81906946715f60916ff1d3400aabe (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 b773294dd380ae81056c3d37b647500aae738ea1 Author: Vladimir V. Kisil <V.Kisilv(a)leeds.ac.uk> Date: Mon Jul 27 21:03:42 2020 +0200 Fix bug in power::expand() with the overall coefficient. The negative sign of overall coefficient had been lost if a power base contained some sign-definite factors. commit 1256fb73b64a1cdfb0838df06facbc1e8b2d5f83 Author: Vladimir V. Kisil <V.Kisilv(a)leeds.ac.uk> Date: Mon Jul 27 20:58:27 2020 +0200 Fix of a bug in sqrfree_parfrac() related to Yun factorisation. Yun's algorithm does not account for constant factors, thus sqrfree_parfrac() dropped such factors in partial fractions. ----------------------------------------------------------------------- Summary of changes: check/exam_paranoia.cpp | 39 +++++++++++++++++++++++++++++++++++++++ ginac/normal.cpp | 18 +++++++++++------- ginac/power.cpp | 5 +++-- 3 files changed, 53 insertions(+), 9 deletions(-) hooks/post-receive -- GiNaC -- a C++ library for symbolic computations

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