September 2014 - GiNaC-list

For more information about software patents in Europe, visit this website: swpat.ffii.org.
by Gustavo de Lama 10 Sep '14

10 Sep '14

For more information about software patents in Europe, visit this website: swpat.ffii.org. That is what appears in the main page (http://www.ginac.de/) but that address redirects you to http://a2e.de/oas/ !!! I suspected http://ffii.org/ had been kidnapped. Alas, no! It seems to be "only" that page. In the hope somebody will be able to fix it. Gustavo de Lama

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[BUG] commit 97ef604e breaks evaluation of some G-polylogs
by Valery Yundin 10 Sep '14

10 Sep '14

Hi, The following commit 97ef604e "G_numeric: fix numeric evaluation with trailing zeros and y != 1." breaks evaluation of G-polylogs with some arguments/ For instance: evalf( G({-1,1,-1,0},1) ); evalf( G({-1,-1,1,-1,0},1) ); evalf( G({-1,0,1,-1,0},1) ); evalf( G({-1,1,-1,-1,0},1) ); evalf( G({-1,1,-1,0,0},1) ); evalf( G({-1,1,-1,1,0},1) ); evalf( G({-1,1,0,-1,0},1) ); evalf( G({-1,1,1,-1,0},1) ); evalf( G({0,-1,1,-1,0},1) ); evalf( G({0,1,1,-1,0},1) ); results in exception: log_eval(): log(0) instead of the correct numerical value. With best regards, Valery Yundin.

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Fwd: GiNaC Bug Report
by Mark Round 08 Sep '14

08 Sep '14

Dear all, The GiNaC feature is_polynomial() returns true in a scenario I feel is false. Namely, 1/(1-x) When running the attached code I obtain, -(-1+x)^(-1).is_polynomial(x) 1 x-(-1+x)^(-1).is_polynomial(x) 0 as output. I observed the result on two computers, MacBook Pro Darwin Kernel version 13.1.0 using GiNaC 1.6.2 64-bit DESY blade server scientific linux 2.6.18-371.1.2.el5 using GiNaC 1.6.2 Additionally, in preparing this report the following variations occurred, 1/(1-pow(x,2)) -> is polynomial 1/(1-pow(x,n)) -> is not polynomial (n being a symbol) 1/(1+x) -> is not polynomial on an SL6 installation running kernel version 2.6.32-431.20.3.el6.x86_64, gcc 4.4.7) using GiNaC 1.6.2 Yours, Mark

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What is the status of xloops?
by Vladyslav Shtabovenko 05 Sep '14

05 Sep '14

Dear all, I know that this is the GiNaC mailing list, but since historically GiNaC was very closely connected to xloops, I think that asking this here is appropriate. Judging from the xloops page (http://wwwthep.physik.uni-mainz.de/~xloops/) the project looks pretty abandoned. The links to the CVS tree and to the mailing list archive give you 404 http://down.physik.uni-mainz.de/cgi-bin/viewcvs.cgi/xloops/?cvsroot=ThEP http://thep.physik.uni-mainz.de/pipermail/xloops-list/ http://thep.physik.uni-mainz.de/pipermail/xloops-devel/ http://thep.physik.uni-mainz.de/pipermail/xloops-cvs/ The most recent version seems to be xloops 0.1.3 from 2002 So, is the xloops library still maintained by someone and is there are working repository to checkout the most recent snapshot somewhere? Cheers, Vladyslav

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dirac_spinor?
by Vladyslav Shtabovenko 05 Sep '14

05 Sep '14

Hi, I started looking at GiNaC only recenty, so forgive me if my question is too naive. I'm wondering if it is possible to define Dirac spinors in the context of Clifford objects, such that they can appear in chains of dirac_gammas. The only property I need at the moment is that dirac_spinor and dirac_gamma do not commute, such that for example dirac_gamma(j)*dirac_gamma(j.togglevariance)*dirac_spinor(p1)*dirac_gamma(i)*dirac_gamma(i.togglevariance)*dirac_spinor(p2)*dirac_gamma(j) will get simplified to 16 dirac_spinor(p1)*dirac_spinor(p2)*dirac_gamma(j) Cheers, Vladyslav

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