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Runtime error
by Pedro Sosa 24 Mar '19

24 Mar '19

Hello I hope somebody could help me at runtime I have an error:terminate called after throwing an instance of 'GiNaC::parse_error' what(): GiNaC: parse error at line 0, column 0: expected EOF, got: "[" [GiNaC::ex GiNaC::parser::operator()(std::istream&)(parser/parser.cpp:232)] the code is: for(int i=0; i< ramaPrim.size();i++) { parser reader; ex e = reader("ramaPrim[i]"); }

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convert from string to ex
by Pedro Sosa 24 Mar '19

24 Mar '19

Hello I have a problem, I would like convert from string to ex to find the symbolic derivativeis it posible?void chequeaPrim(vector<string> ramaPrim) { for(int i=0; i< ramaPrim.size();i++) { ex = ramaPrim[i]; } } thanks

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Compilation
by Pedro Sosa 13 Mar '19

13 Mar '19

Hello, I install in my Ubuntu Ginac but I don't know how to compile a basic example #include <iostream> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { symbol x("x"), y("y"); for (int i=0; i<3; ++i) poly += factorial(i+16)*pow(x,i)*pow(y,2-i); cout << poly << endl; return 0; } where I must put this file for ginac.h can be visiblethanks PS: /usr/include/ginac/ginac.h

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cmake patch to find correct python executable
by Till Hofmann 17 Feb '19

17 Feb '19

Hi all, Please consider including the attached patch. With this patch, cmake searches for the correct path of the python2 interpreter and uses that path for calling python, instead of just calling "python". This fixes a bug on Fedora, which no longer has an unversioned python interpreter (i.e., only python2 and python3). It should also avoid using python3 on accident. On a related note, are there any plans to switch to python3? I only had a quick glance and there are some incompatibilities, but most of them seem to be rather straight-forward to fix. Thanks! Till

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Release 1.7.5
by Richard B. Kreckel 17 Feb '19

17 Feb '19

Hi, A new GiNaC version has just been released. The changes are: * Add Markowitz-ordered Gaussian elimination. * Avoid un-normal zeros in matrix::solve(). * Accept exprseq arguments in lsolve(eqns, vars). * Add overload of matrix::rank(solve_algo). * Fix case in G_do_hoelder with real x values which are not cl_R. * Fix an elusive bug in expairseq/add ctor, introduced in 1.7.0. Happy hacking! -richy.

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bug in diff
by Mario Prausa 16 Feb '19

16 Feb '19

Hi, I found a bug in the diff function. The attached code produces: a: -1 b: 2 c: 1+0 The derivative with respect to c is not simplified completely. I tested this with both GiNaC 1.7.4 and the git version. Cheers, Mario

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[patch] Fix a failure in matrix::division_free_elimination()
by Vitaly Magerya 12 Oct '18

12 Oct '18

Hi, folks. I've run into another case of matrix::solve() failing. This time it seems like the division-free elimination doesn't handle un-normal zeros properly: currently it only does expand() (instead of normal()) on the results of it's calculations, but then uses matrix::pivot() to find the pivot, and that routine also uses expand().is_zero() for zero testing. This breaks when fractions are present in the initial matrix. Not every time, but at least in one example. Note that this problem also affects matrix::solve() with 'algo' set to solve_algo::automatic, which is how I encountered it. I'm attaching the example added to the tests, and also the fix that makes matrix::division_free_elimination() use normal() in stead of expand(). An alternative would be to use normal() in the matrix::pivot() routine, but I decided against it because: 1) that way the results of the normal() call would be discarded; 2) that could slow down e.g. matrix::gauss_elimination() which also uses matrix::pivot(), but normalizes expressions itself. Of course, using normal() makes division_free_elimination only truly "division-free" if the input matrix didn't have fractions. In other cases, GCDs will be computed.

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Building of GINAC fails at compiling GINSH and linking of CLN
by Oleg Kmechak 20 Sep '18

20 Sep '18

Hello, I am student on Physics Faculty at University of Warsaw and new to GINAC. Currently just trying to build it from git repository. first case: I installed and build up CLN(to default /usr/local dir), then I tried to build GINAC. second case: I installed cln from running command sudo apt install libcln-dev and once again tried to build GINAC. Next everything was as described in INSTALL file from GINAC folder: autoreconf -iv ./configure make -j 4 and at some moment it returned: /usr/include/cln/object.h:212: undefined reference to `cln::cl_free_heap_object(cln::cl_heap*)' collect2: error: ld returned 1 exit status Makefile:474: recipe for target 'ginsh' failed make[2]: *** [ginsh] Error 1 Also please see full log attached below

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Re: [GiNaC-list] Welcome to the "GiNaC-list" mailing list
by Patrick Schulz 07 Sep '18

07 Sep '18

Hi all! I'm working with polynomials in one variable, where i want to compare coefficients and remove some (simplification). For this, i need to iterate over the individual coefficients, but in order to compare them, i need them to be in a standard form. Since only terms with products and sums are involved, i expand the expressions to remove any nested expressions, e.g. R1 * (C1 + C2) -> R1 * C1 + R1 * C2. This works well, but sometime terms of nth power also exist, which are not expanded: GiNaC::symbol R1("R1"); GiNaC::symbol R2("R2"); GiNaC::symbol C1("C1"); GiNaC::symbol C2("C2"); GiNaC::ex e = (R1 + R2) * (C1 + C2 * (R1 * C1)); std::cout << e << '\n' << e.expand() << '\n'; Here we get a term R1^2 * C1 * C2, which does not comply with my "standard form". In the end, ideally i would like to have only a sum of products, no deeper nesting: R1 * C1 + R1 * R1 * C1 * C2 + R2 * C1 + R1 * R2 * C1 * C2 Is there a way to do this? Maybe some information what i'm trying to acchieve: I solve spice netlists and extract transfer functions in s-space. For the simplification (the removal of individual terms) i want to look at the coefficients of the numerator and the denominator polynoms. This is easy, since i use ex::coeff(). So now i have expressions for each power of s. Then i want to store the individual elements in a vector, which makes up the individual products. These are again stored in another vector making up the sum of the polynoms. This works, kinda, but i have to parse the ginac expression, which does not always behave in a way i can foresee. Also i have a strong feeling that there is a better way to do this, given that ginac has already many functions dealing with polynoms. I'm happy to get some pointers on this topic :) Thank you for your help! Greetings, Patrick

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Bug report
by 杨强 24 Aug '18

24 Aug '18

Dear all, I use GiNaC to perform analytic calculation, but when I try to use .numer() and .denom() methods, I get a wrong result. 1. expr.numer()/expr.denom() is not always equal to the original expression!!! 2. Using .numer_denom() method could always get the correct answer. I attach a simple code source file and logger file to check that problem. The logger file will be different when you run the code on your computer. Yours, Yang

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