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Release 1.6.3
by Richard B. Kreckel 28 Nov '14

28 Nov '14

Hi everybody, Alexei and I have prepared a new release and are happy to announce that GiNaC 1.6.3 is out and available. These are the changes: * New expand_options::expand_transcendental. GiNaC will apply additional rules when expanding expressions if this option is specified, i.e. log(a*b) -> log(a) + log(b) exp(a + b) -> exp(a)*exp(b) * Functions can define a custom expand() and info() now. * Automatically rewrite (x^{-1})^c -> x^{-c} for positive c. * Transform abs(x)^n -> x^n if x is real and n is even. * Improved power::info(): power with a real base and even exponent reports that it's non-negative. * Fixed spurious match failure due to expairseq::match() bug: > match(sin(y)*exp(b)+sin(x)*exp(a), sin($0)*exp(a)+exp(b)*sin($1)) FAIL * Fixed power::is_polynomial() and mul::is_polynomial() computation. * factor_univariate correctly handles polynomials over rationals (no segfaults any more). * Fixed an infinite loop in factor_multivariate due to incorrect handling of polynomials having a leading coefficient being a sum with a non-trivial integer content. * Fixed numeric evaluation of generalized multiple polylogarithms for real and negative argument. * Avoid calling log(1-x) in numeric evaluation of classical polylogarithm. * Fixed numeric evaluation of multiple polylogarithms (correctly set the signs of the imaginary parts in the intermediate expression). * Fixed numeric evaluation of Nielsen polylogs for arguments close to the 6th root of unity or its conjugate. * Avoid infinite recursion in series expansion of logarithm. * numeric::info(info_flags::nonnegative) correctly handles complex numbers with non-zero imaginary part. * Fixed several build issues: - libreadline and dlopen() misdetection. - multiple definition of symbol on MinGW. - auto* tools and texinfo being unhappy in various ways. * GiNaC can be built with CMake now. Regards, -richy. -- Richard B. Kreckel <http://in.terlu.de/~kreckel/>

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How to put variables to the second argument of ex::ex()
by Shi 16 Nov '14

16 Nov '14

Hello, I'd like to convert std::string to ex constructor. But my code do not work now. How to put variables to the second argument of ex(const std::string &s, const ex &l). ----Code: #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main(){ string st("2*a+3*sqrt(4)*b"); symbol a("a"), b("b"); ex sample(st, ex(a)); cout << sample <<endl; return 0; } ----Excuted: terminate called after throwing an instance of 'std::invalid_argument' what(): find_or_insert_symbol: symbol "a" not found IOT trap

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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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finite fields?
by Ruben Zilibowitz 26 Aug '14

26 Aug '14

Is there any support in GiNaC for factoring polynomials over finite fields or rings? Regards, Ruben

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subs on matrices
by Ruben Zilibowitz 25 Jul '14

25 Jul '14

Is there any reason not to include a subs function on the matrix class? Regards, Ruben

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ex::is_polynomial function
by Ruben Zilibowitz 24 Jul '14

24 Jul '14

The following code is not working as I would expect. The expression ‘m + sqrt(d)’ is surely a polynomial in m. However GiNaC thinks it is not. { symbol m("m"), d("d"); ex e = m + sqrt(d); cout << e << " is polynomial in m " << e.is_polynomial(m) << endl; } Regards, Ruben

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