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Access denied when cloning git repository
by Matthias Volk 08 Jul '24

08 Jul '24

Hello, I am trying the clone the GiNaC and CLN git repositories. Both commands git clone git://www.ginac.de/cln.git and git clone git://www.ginac.de/ginac.git fail with the following error message: fatal: remote error: access denied or repository not exported: /ginac.git Am I using a wrong command or are the git repositories currently not available? Best regards, Matthias

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degree function
by Santos Jha 04 Jul '24

04 Jul '24

Greetings, I am new to GiNac. I was trying to use the degree function, but I got a weird result. My initial expression is -4*(-3+x)*(-1+x)+9/2*(-2+x)*(-1+x)+1/2*(-2+x)*(-3+x) After the "expand" function call, it returns 9/2*x^2-5/2*x-4*x^2+16*x-27/2*x+1/2*x^2 My goal is to add/subtract the coefficient of equal degree terms. I could not find any function for that. ( if it is already there, please point me) I wanted to write a function to achieve it. To do so. I am taking each term and try to see if for (size_t i = 0; i != poly.nops(); ++i) { // Here poly is polynomial as above ex subExpres=poly.op(i); // I get individual terms cout << "is polynomial="<< is_polynomial(subExpres,symb) <<endl; // GiNaC::ex pow2=pow(symb,2); cout << subExpres<< " degree=" << subExpres.degree(symb) << endl; } It determines the subexpression as a polynomial but can not determine the degree. E.g is polynomial=1 9/2*x^2 degree=0 // Here degree returned is wrong. Your thoughts will be appreciated. Regards, Santos

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Ginsh Compiler Issues on Mac OS
by Francesca C Fernandes 29 Jun '24

29 Jun '24

Hello, I am trying to install GINAC on Mac OS. ginsh did not install because it could not find readline. I have already installed readline using Homebrew, and homebrew gave me the message appended below. So I used this configure option: ./configure LDFLAGS="-L/usr/local/opt/readline/lib" CPPFLAGS="-I/usr/local/opt/readline/include" PKG_CONFIG_PATH="/usr/local/opt/readline/lib/pkgconfig" Unfortunately, ginsh still does not compile and I get this information from configure: ***** BEGIN MESSAGE FROM CONFIGURE***** == ginsh will not compile, because libreadline could not be found. *****END MESSAGE FROM CONFIGURE***** *Could you please help me with the configure options to get ginsh to compile?* I’ve attached the config.log as well. Thank you! Sincerely, Francesca *****BEGIN MESSAGE FROM HOMEBREW **** For compilers to find readline you may need to set: export LDFLAGS="-L/usr/local/opt/readline/lib" export CPPFLAGS="-I/usr/local/opt/readline/include" For pkg-config to find readline you may need to set: export PKG_CONFIG_PATH="/usr/local/opt/readline/lib/pkgconfig" readline is keg-only, which means it was not symlinked into /usr/local, because macOS provides BSD libedit. For compilers to find readline you may need to set: export LDFLAGS="-L/usr/local/opt/readline/lib" export CPPFLAGS="-I/usr/local/opt/readline/include" For pkg-config to find readline you may need to set: export PKG_CONFIG_PATH="/usr/local/opt/readline/lib/pkgconfig" ******END MESSAGE FROM HOMEBREW******

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bugs in indexed object
by Dr. Mithun Bairagi 14 Apr '24

14 Apr '24

Dear all ginac lovers, I have found simplify_indexed() is not working as expected. I have compiled and run the following c++ program using ginac 1.87 (mingw64 compiler, windows 10 os), #include <ginac/ginac.h> using namespace GiNaC; using namespace std; int main() { symbol A("A"), B("B"), C("C"), i_sym("i"),j_sym("j"); varidx i(i_sym, 3); varidx ic(i_sym, 3,true); varidx j(j_sym, 3); varidx jc(j_sym, 3,true); ex e = indexed(A, {i,i}) * indexed(B, {ic,ic})-indexed(A, {j,j}) * indexed(B, {jc,jc}); cout << (e).simplify_indexed() << endl; return 0; } the above program shows the following result: A.i.i*B~symbol16.symbol16-A.i.i*B~symbol17.symbol17 But I think the result should be zero. Please tell me what is the problem here? Best regards, Mithun Bairagi

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GPL v2 and v3 compatibility issues
by Diddens, Christian (UT-TNW) 13 Apr '24

13 Apr '24

Dear GiNaC team, first of all, thanks so much for your powerful projects GiNaC and CLN! Thanks so much for making them open to us all! Based on your projects (and others), I have developed a nice multi-physics finite element framework, which I would like to share with the world soon. Of course, I will also go for the GPL, but I get conflicts, since I also have another dependency (pygmsh) using GPL v3, which is not compatible with GPL v2 of GiNaC and CLN. I total, I have to satisfy BSD-3-Clause, BSD-2-Clause, MIT, LGPL-2.1-only, LGPL-2.1-or-later, GPL-2.0-or-later, GPL-2.0-only and GPL-3.0-only. This configuration is not compatible under any outbound licence, unless I leave out either the GPL-2.0-only dependencies (GiNaC & CLN) or the GPL-3.0-only dependency (pygmsh). Of course, I have read your statement in the FAQ: ---- I don't like the GPL. May I have another license, please? A: The idea to dual-license GiNaC has been proposed a number of times. It has, however, been squarely rejected by some developers. Asking for a permission to dual-license it is likely going to waste your valuable time. That being said: The GPL is a good license. Why not directly put derived work under the GPL, too? ---- I am not asking for a dual-license, I support the ideas of the GPL myself, but I just wonder whether there are any plans to go for GPL-2.0-or-later at any time? If not, I have to get rid of the GPL-3.0 dependency, i.e. write my own interface to gmsh, before I can publish my work under GPL-2.0-only as well. Thanks for any information, help or suggestions in this issue! Best regards, Christian

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bug in ex::ex(const std::string&, const ex&)
by Diego Conti 05 Apr '24

05 Apr '24

Hi, I think there is a bug in the functions that convert strings to ex. I attach a minimal program that segfaults on my machine. I am using gcc 13.2.0 on Ubuntu 23.10, x86_64, CPU Intel i9-12900H. The problem only arises if I compile GiNaC using the CMake script. The same program works if I compile with configure && make. The problem appears to be in parser/default_reader.cpp, where conversions between pointers to functions and integers are used. The code assumes that the integer underlylng a pointer to function is even, relying on the fact that functions are aligned; this latter condition appears to fail on my system when compiling with CMake. Indeed, inserting a pragma command inside parser/default_reader.cpp (see attached patch) fixes the problem. I do not know if this can be made portable across compilers; maybe it would be easier to modify the code by replacing reader_func with a class that handles the conversion in a type-safe way? Diego Conti

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Can GiNaC Solve Nonlinear Equations?
by Marius Einstein 10 Feb '24

10 Feb '24

Hi! I am solving a problem that requires to solve nonlinear equations like {x1^2+x2^2=u1, x1+x2=u2}. Can GiNaC solve nonlinear equations like this? Thanks, Erick Farestveit

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Usage of designated initializer in factor.cpp forces c++20 on GiNaC
by Igor Machado 28 Oct '23

28 Oct '23

Dear all, congratulations for this amazing software. I was struggling a little bit to make it work in CMake, with many linking errors in windows (for linux it was easy, but I need both working) so I recently created a simple Bazel build file for the projects CLN and GINAC, to debug the error. In the end, I managed to find and fix the error, so I wanted you to know that the file factor.cpp from GiNaC is using designated initializers, which is only part of c++20... and when I activated c++20 here, the linking was broken on windows! So, a solution was to change (around line 2344): factorization_ctx ctx = {.poly = poly, .x = x, .syms_wox = syms_wox}; And transform into this: factorization_ctx ctx{poly, x, syms_wox}; After that, I can enable c++17 and it works on GCC, Clang and MSVC! For GCC and Clang, they don't complain on designated initializers, even if it's c++17 standard... So, since it's the only thing from c++20, you should consider if it's work activating a whole new standard just because of this, or to consider that the project is already c++20. I personally love c++20, but it's important to notice that some fundamental things change... for example, I just discovered that the code works in c++20 in windows, but with /permissive flag, otherwise it gives crazy LNK2019 linking errors. I believe some ABI has changed after c++17, but it was hard to understand and fix the error. So, best regards and I hope this information is useful! Igor

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Polynomial Zeros
by Charles White 11 Oct '23

11 Oct '23

Hi GiNaC! Is there a built-in method to find all zeros of a polynomial? I'm trying to find symbolic zeros if possible and numeric zeros for all other cases. Thanks! Charles

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series((x+x^2)^2,x,0) is broken
by Vitaly Magerya 15 Aug '23

15 Aug '23

Hi, all. I'm trying to expand expressions into series, and I've run into a case which looks broken (with the latest GiNaC): ginsh> series((x+x^2)^2,x,0); (Order(1)^2)*x^(-2)+Order(1) What I expect is Order(1) here, because the expression starts at O(x^2). Same problem with e.g. (x+sin(x))^2, and lots of other expressions. It seems that any non-trivial expression that starts at O(x) or higher to a power expands into this sort of an unhelpful result. Note that trying to remove the Order() parts does not work: ginsh> series_to_poly(series((x+x^2)^2,x,0)); x^(-2)*Order(1)^2 What I expect here is "0" instead. Any ideas on what's going on and how to fix it?

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