- GiNaC-list - ginac.de

Possible bug in factor()
by tluthe＠physik.uni-bielefeld.de 18 May '14

18 May '14

Hi, there appears to be a bug in the multivariate factor() routine. For some expressions it seems to get stuck in an infinite loop, without any result or error messages appearing. The simplest expression I could find to reproduce this behaviour consistently is the expanded form of (3*x+2*y)*(x+y+x*y). For some other expressions (e.g. (x+2*y)*(x+y+x*y)) the problem occurs randomly, but not all the time. I'm guessing this is due to the randomness of the internal ordering of symbols. A minimal example code exhibiting the problem is attached. I've reproduced this bevahiour on openSuse and Ubuntu machines using GiNaC 1.6.2 and CLN 1.3.2. Regards, Thomas

2 1

Example Input Program Hanging Up
by Casey Conger 03 Feb '14

03 Feb '14

Hello all, I’m having trouble with running the example interactive program from the tutorial. I simply cut and pasted it, but after it asks for “an expression involving ‘x’ “ it just hangs and never does anything. The problem seems to be in the line ‘ex e = reader(cin)’, I got the other examples to run just fine, but the reader(cin) seems to be problematic. My setup: Macbook Air1.5GHZ i7, OSX 10.9.1, ginac 1.6.2 My program: #include <iostream> #include <string> #include <stdexcept> #include <ginac/ginac.h> using namespace std; using namespace GiNaC; int main() { cout << "Enter an expression containing ’x’: " << flush; parser reader; try { ex e = reader(cin); symtab table = reader.get_syms(); symbol x = table.find("x") != table.end() ? ex_to<symbol>(table["x"]) : symbol("x"); cout << "The derivative of " << e << " with respect to x is "; cout << e.diff(x) << "." << endl; } catch (exception &p) { cerr << p.what() << endl; } } Commandline: Caseys-MacBook-Air:ginac casey$ g++ ginacPlay.cpp -o ginacPlay.out -lginac -lcln Caseys-MacBook-Air:ginac casey$ ./ginacPlay.out Enter an expression containing ’x’: x ^C …It just hangs there for several minutes.

2 1

Stay in touch with me through LinkedIn
by Jose Antonio Garcia Peiro 29 Jan '14

29 Jan '14

LinkedIn ------------ Me gustaría añadirte a mi red profesional en LinkedIn. -Jose Antonio Jose Antonio Garcia Peiro Estudiante de Universidad Miguel Hernández de Elche Murcia y alrededores, España Confirm that you know Jose Antonio Garcia Peiro: https://www.linkedin.com/e/-qmwzwc-hr0w8crr-5d/isd/4281101300/r-1XX1c3/?hs=… -- You are receiving Invitation to Connect emails. Click to unsubscribe: http://www.linkedin.com/e/-qmwzwc-hr0w8crr-5d/kGy7Yg-6HHAoBPMg-Y4n5eWUQMwWs… (c) 2012 LinkedIn Corporation. 2029 Stierlin Ct, Mountain View, CA 94043, USA.

1 0

Problems running ginac on OSX 10.9
by Casey Conger 19 Jan '14

19 Jan '14

Hello, I apologize in advance because I am extremely bad with anything beyond simple computing. My Setup: OSX 10.9.1, gcc4.8 My Situation: After some trouble compiling, I finally was able make/ make install with no errors. Now when I try to run one of the example programs, it doesn’t compile. I see all of the header files located in /usr/local/include/ginac. I try to compile with g++ derivative.cpp -I /usr/local/include or g++ derivative.cpp -L /usr/local/include but I get the following: Caseys-MacBook-Air:examples casey$ g++ derivative.cpp -I/usr/local/include/ Undefined symbols for architecture x86_64: "GiNaC::library_init::library_init()", referenced from: ___cxx_global_var_init in derivative-sy6zT0.o "GiNaC::library_init::~library_init()", referenced from: ___cxx_global_var_init in derivative-sy6zT0.o "GiNaC::add_unarchiver::add_unarchiver()", referenced from: ___cxx_global_var_init18 in derivative-sy6zT0.o "GiNaC::add_unarchiver::~add_unarchiver()", referenced from: ___cxx_global_var_init18 in derivative-sy6zT0.o "GiNaC::idx_unarchiver::idx_unarchiver()", referenced from: ___cxx_global_var_init22 in derivative-sy6zT0.o "GiNaC::idx_unarchiver::~idx_unarchiver()", referenced from: ___cxx_global_var_init22 in derivative-sy6zT0.o "GiNaC::lst_unarchiver::lst_unarchiver()", referenced from: ___cxx_global_var_init2 in derivative-sy6zT0.o "GiNaC::lst_unarchiver::~lst_unarchiver()", referenced from: ___cxx_global_var_init2 in derivative-sy6zT0.o "GiNaC::mul_unarchiver::mul_unarchiver()", referenced from: ___cxx_global_var_init19 in derivative-sy6zT0.o "GiNaC::mul_unarchiver::~mul_unarchiver()", referenced from: ___cxx_global_var_init19 in derivative-sy6zT0.o "GiNaC::fail_unarchiver::fail_unarchiver()", referenced from: ___cxx_global_var_init4 in derivative-sy6zT0.o "GiNaC::fail_unarchiver::~fail_unarchiver()", referenced from: ___cxx_global_var_init4 in derivative-sy6zT0.o "GiNaC::su3d_unarchiver::su3d_unarchiver()", referenced from: ___cxx_global_var_init34 in derivative-sy6zT0.o "GiNaC::su3d_unarchiver::~su3d_unarchiver()", referenced from: ___cxx_global_var_init34 in derivative-sy6zT0.o "GiNaC::su3f_unarchiver::su3f_unarchiver()", referenced from: ___cxx_global_var_init33 in derivative-sy6zT0.o "GiNaC::su3f_unarchiver::~su3f_unarchiver()", referenced from: ___cxx_global_var_init33 in derivative-sy6zT0.o "GiNaC::su3t_unarchiver::su3t_unarchiver()", referenced from: ___cxx_global_var_init32 in derivative-sy6zT0.o "GiNaC::su3t_unarchiver::~su3t_unarchiver()", referenced from: ___cxx_global_var_init32 in derivative-sy6zT0.o "GiNaC::color_unarchiver::color_unarchiver()", referenced from: ___cxx_global_var_init30 in derivative-sy6zT0.o "GiNaC::color_unarchiver::~color_unarchiver()", referenced from: ___cxx_global_var_init30 in derivative-sy6zT0.o "GiNaC::ncmul_unarchiver::ncmul_unarchiver()", referenced from: ___cxx_global_var_init10 in derivative-sy6zT0.o "GiNaC::ncmul_unarchiver::~ncmul_unarchiver()", referenced from: ___cxx_global_var_init10 in derivative-sy6zT0.o "GiNaC::power_unarchiver::power_unarchiver()", referenced from: ___cxx_global_var_init8 in derivative-sy6zT0.o "GiNaC::power_unarchiver::~power_unarchiver()", referenced from: ___cxx_global_var_init8 in derivative-sy6zT0.o "GiNaC::matrix_unarchiver::matrix_unarchiver()", referenced from: ___cxx_global_var_init6 in derivative-sy6zT0.o "GiNaC::matrix_unarchiver::~matrix_unarchiver()", referenced from: ___cxx_global_var_init6 in derivative-sy6zT0.o "GiNaC::su3one_unarchiver::su3one_unarchiver()", referenced from: ___cxx_global_var_init31 in derivative-sy6zT0.o "GiNaC::su3one_unarchiver::~su3one_unarchiver()", referenced from: ___cxx_global_var_init31 in derivative-sy6zT0.o "GiNaC::symbol_unarchiver::symbol_unarchiver()", referenced from: ___cxx_global_var_init11 in derivative-sy6zT0.o "GiNaC::symbol_unarchiver::~symbol_unarchiver()", referenced from: ___cxx_global_var_init11 in derivative-sy6zT0.o "GiNaC::unarchive_table_t::unarchive_table_t()", referenced from: ___cxx_global_var_init1 in derivative-sy6zT0.o "GiNaC::unarchive_table_t::~unarchive_table_t()", referenced from: ___cxx_global_var_init1 in derivative-sy6zT0.o "GiNaC::varidx_unarchiver::varidx_unarchiver()", referenced from: ___cxx_global_var_init23 in derivative-sy6zT0.o "GiNaC::varidx_unarchiver::~varidx_unarchiver()", referenced from: ___cxx_global_var_init23 in derivative-sy6zT0.o "GiNaC::get_default_reader()", referenced from: _main in derivative-sy6zT0.o "GiNaC::indexed_unarchiver::indexed_unarchiver()", referenced from: ___cxx_global_var_init15 in derivative-sy6zT0.o "GiNaC::indexed_unarchiver::~indexed_unarchiver()", referenced from: ___cxx_global_var_init15 in derivative-sy6zT0.o "GiNaC::numeric_unarchiver::numeric_unarchiver()", referenced from: ___cxx_global_var_init7 in derivative-sy6zT0.o "GiNaC::numeric_unarchiver::~numeric_unarchiver()", referenced from: ___cxx_global_var_init7 in derivative-sy6zT0.o "GiNaC::pseries_unarchiver::pseries_unarchiver()", referenced from: ___cxx_global_var_init16 in derivative-sy6zT0.o "GiNaC::pseries_unarchiver::~pseries_unarchiver()", referenced from: ___cxx_global_var_init16 in derivative-sy6zT0.o "GiNaC::spinidx_unarchiver::spinidx_unarchiver()", referenced from: ___cxx_global_var_init24 in derivative-sy6zT0.o "GiNaC::spinidx_unarchiver::~spinidx_unarchiver()", referenced from: ___cxx_global_var_init24 in derivative-sy6zT0.o "GiNaC::clifford_unarchiver::clifford_unarchiver()", referenced from: ___cxx_global_var_init35 in derivative-sy6zT0.o "GiNaC::clifford_unarchiver::~clifford_unarchiver()", referenced from: ___cxx_global_var_init35 in derivative-sy6zT0.o "GiNaC::constant_unarchiver::constant_unarchiver()", referenced from: ___cxx_global_var_init3 in derivative-sy6zT0.o "GiNaC::constant_unarchiver::~constant_unarchiver()", referenced from: ___cxx_global_var_init3 in derivative-sy6zT0.o "GiNaC::diracone_unarchiver::diracone_unarchiver()", referenced from: ___cxx_global_var_init36 in derivative-sy6zT0.o "GiNaC::diracone_unarchiver::~diracone_unarchiver()", referenced from: ___cxx_global_var_init36 in derivative-sy6zT0.o "GiNaC::function_unarchiver::function_unarchiver()", referenced from: ___cxx_global_var_init20 in derivative-sy6zT0.o "GiNaC::function_unarchiver::~function_unarchiver()", referenced from: ___cxx_global_var_init20 in derivative-sy6zT0.o "GiNaC::integral_unarchiver::integral_unarchiver()", referenced from: ___cxx_global_var_init5 in derivative-sy6zT0.o "GiNaC::integral_unarchiver::~integral_unarchiver()", referenced from: ___cxx_global_var_init5 in derivative-sy6zT0.o "GiNaC::symmetry_unarchiver::symmetry_unarchiver()", referenced from: ___cxx_global_var_init17 in derivative-sy6zT0.o "GiNaC::symmetry_unarchiver::~symmetry_unarchiver()", referenced from: ___cxx_global_var_init17 in derivative-sy6zT0.o "GiNaC::wildcard_unarchiver::wildcard_unarchiver()", referenced from: ___cxx_global_var_init14 in derivative-sy6zT0.o "GiNaC::wildcard_unarchiver::~wildcard_unarchiver()", referenced from: ___cxx_global_var_init14 in derivative-sy6zT0.o "GiNaC::possymbol_unarchiver::possymbol_unarchiver()", referenced from: ___cxx_global_var_init13 in derivative-sy6zT0.o "GiNaC::possymbol_unarchiver::~possymbol_unarchiver()", referenced from: ___cxx_global_var_init13 in derivative-sy6zT0.o "GiNaC::tensdelta_unarchiver::tensdelta_unarchiver()", referenced from: ___cxx_global_var_init25 in derivative-sy6zT0.o "GiNaC::tensdelta_unarchiver::~tensdelta_unarchiver()", referenced from: ___cxx_global_var_init25 in derivative-sy6zT0.o "GiNaC::diracgamma_unarchiver::diracgamma_unarchiver()", referenced from: ___cxx_global_var_init37 in derivative-sy6zT0.o "GiNaC::diracgamma_unarchiver::~diracgamma_unarchiver()", referenced from: ___cxx_global_var_init37 in derivative-sy6zT0.o "GiNaC::minkmetric_unarchiver::minkmetric_unarchiver()", referenced from: ___cxx_global_var_init27 in derivative-sy6zT0.o "GiNaC::minkmetric_unarchiver::~minkmetric_unarchiver()", referenced from: ___cxx_global_var_init27 in derivative-sy6zT0.o "GiNaC::realsymbol_unarchiver::realsymbol_unarchiver()", referenced from: ___cxx_global_var_init12 in derivative-sy6zT0.o "GiNaC::realsymbol_unarchiver::~realsymbol_unarchiver()", referenced from: ___cxx_global_var_init12 in derivative-sy6zT0.o "GiNaC::relational_unarchiver::relational_unarchiver()", referenced from: ___cxx_global_var_init9 in derivative-sy6zT0.o "GiNaC::relational_unarchiver::~relational_unarchiver()", referenced from: ___cxx_global_var_init9 in derivative-sy6zT0.o "GiNaC::spinmetric_unarchiver::spinmetric_unarchiver()", referenced from: ___cxx_global_var_init28 in derivative-sy6zT0.o "GiNaC::spinmetric_unarchiver::~spinmetric_unarchiver()", referenced from: ___cxx_global_var_init28 in derivative-sy6zT0.o "GiNaC::tensmetric_unarchiver::tensmetric_unarchiver()", referenced from: ___cxx_global_var_init26 in derivative-sy6zT0.o "GiNaC::tensmetric_unarchiver::~tensmetric_unarchiver()", referenced from: ___cxx_global_var_init26 in derivative-sy6zT0.o "GiNaC::diracgamma5_unarchiver::diracgamma5_unarchiver()", referenced from: ___cxx_global_var_init38 in derivative-sy6zT0.o "GiNaC::diracgamma5_unarchiver::~diracgamma5_unarchiver()", referenced from: ___cxx_global_var_init38 in derivative-sy6zT0.o "GiNaC::diracgammaL_unarchiver::diracgammaL_unarchiver()", referenced from: ___cxx_global_var_init39 in derivative-sy6zT0.o "GiNaC::diracgammaL_unarchiver::~diracgammaL_unarchiver()", referenced from: ___cxx_global_var_init39 in derivative-sy6zT0.o "GiNaC::diracgammaR_unarchiver::diracgammaR_unarchiver()", referenced from: ___cxx_global_var_init40 in derivative-sy6zT0.o "GiNaC::diracgammaR_unarchiver::~diracgammaR_unarchiver()", referenced from: ___cxx_global_var_init40 in derivative-sy6zT0.o "GiNaC::fderivative_unarchiver::fderivative_unarchiver()", referenced from: ___cxx_global_var_init21 in derivative-sy6zT0.o "GiNaC::fderivative_unarchiver::~fderivative_unarchiver()", referenced from: ___cxx_global_var_init21 in derivative-sy6zT0.o "GiNaC::tensepsilon_unarchiver::tensepsilon_unarchiver()", referenced from: ___cxx_global_var_init29 in derivative-sy6zT0.o "GiNaC::tensepsilon_unarchiver::~tensepsilon_unarchiver()", referenced from: ___cxx_global_var_init29 in derivative-sy6zT0.o "GiNaC::basic::basic(GiNaC::basic const&)", referenced from: GiNaC::symbol::symbol(GiNaC::symbol const&) in derivative-sy6zT0.o "GiNaC::parser::parser(std::__1::map<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, GiNaC::ex, std::__1::less<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > >, std::__1::allocator<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const, GiNaC::ex> > > const&, bool, std::__1::map<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, unsigned long>, GiNaC::ex (*)(std::__1::vector<GiNaC::ex, std::__1::allocator<GiNaC::ex> > const&), GiNaC::PrototypeLess, std::__1::allocator<std::__1::pair<std::__1::pair<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, unsigned long> const, GiNaC::ex (*)(std::__1::vector<GiNaC::ex, std::__1::allocator<GiNaC::ex> > const&)> > > const&)", referenced from: _main in derivative-sy6zT0.o "GiNaC::parser::~parser()", referenced from: _main in derivative-sy6zT0.o "GiNaC::parser::operator()(std::__1::basic_istream<char, std::__1::char_traits<char> >&)", referenced from: _main in derivative-sy6zT0.o "GiNaC::symbol::symbol(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)", referenced from: _main in derivative-sy6zT0.o "GiNaC::_num0_bp", referenced from: GiNaC::ex::ex() in derivative-sy6zT0.o "GiNaC::operator<<(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, GiNaC::ex const&)", referenced from: _main in derivative-sy6zT0.o "GiNaC::ex::diff(GiNaC::symbol const&, unsigned int) const", referenced from: _main in derivative-sy6zT0.o "vtable for GiNaC::basic", referenced from: GiNaC::basic::~basic() in derivative-sy6zT0.o NOTE: a missing vtable usually means the first non-inline virtual member function has no definition. "vtable for GiNaC::symbol", referenced from: GiNaC::symbol::~symbol() in derivative-sy6zT0.o GiNaC::symbol::symbol(GiNaC::symbol const&) in derivative-sy6zT0.o NOTE: a missing vtable usually means the first non-inline virtual member function has no definition. ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code 1 (use -v to see invocation) It seems like it just can’t find these functions, but I have no idea why. Thank you in advance for your help. -Casey

1 0

Randomness when using lsolve
by Federico Bergero 16 Jan '14

16 Jan '14

Hello everybody I'm new to GiNaC. I'm trying to use it to solve linear algebraic system of equations and running the example from the tutorial https://www.ginac.de/tutorial/Solving-linear-systems-of-equations.html#Solv… symbol a("a"), b("b"), x("x"), y("y"); lst eqns, vars; eqns = a*x+b*y==3, x-y==b; vars = x, y; cout << lsolve(eqns, vars) << endl; While it works perfectly when I run it several times I get different solutions (they are all equivalent though). For example: {x==(3+b^2)*(a+b)^(-1),y==-(a+b)^(-1)*(-3+a*b)} or {x==(b+a)^(-1)*(3+b^2),y==-(-3+b*a)*(b+a)^(-1)} what is going on there? Is there a way to have a deterministic solution? Thanks in advance. Fede -- I find television very educational. Every time someone switches it on, I go into another room and read a good book.

2 2

Symbolic integration of trigonometric functions
by Jan 27 Dec '13

27 Dec '13

Hi, the Ginac documentation says: "GiNaC is not very good (yet?) at symbolically evaluating integrals" so I though I might help it along. Code for sin() and cos() is in this branch which is based on the current master: https://github.com/jrheinlaender/ginac/tree/jrheinlaender/integral and if you like it I might add more functions. Jan Rheinländer

1 0

Fwd: GiNaC error when trying to evaluate sin(x)^2 expression
by José Pontes 22 Dec '13

22 Dec '13

Hi, When subsiting x by a float in a sin(x)^2 expression, I get the following error: libc++abi.dylib: terminating with uncaught exception of type cln::notreached_exception: Internal error: statement in file float/elem/cl_F_square.cc, line 21 has been reached!! using this code: symbol x; ex exTest = sin(x)*sin(x); exmap map; map[x] = 1.0; cout << exTest.subs(map) << endl; I need to do similar substitutions in a matrix, and they allways fail for expressions that contain cos(x)^2 or sin(x)^2, but no for ones that contain cos(x)*sin(x), for example. Can you help me understanding this error and/or getting around it? Regards

2 1

Compiling GiNaC on OS X
by David Seery 30 Oct '13

30 Oct '13

Hello, >> From the error message I can conclude that there are two constructors >> applyable - which one is the correct one? E.g. casting 0 to ex (changing >> the line to: H(lst( ex(0) ),1/arg).hold() solves the error - is this the >> correct cast or is the other cast the correct one? > > According to the manual, the harmonic polylogarithm H expects a general > lst as first argument. So, lst(ex(0)) is correct and lst(int(0)) would > be incorrect. > > But I wonder why this clarification is needed. IMHO, the first candidate > shouldn't be considered, if the std::list<T>(T) ctor is explicit, or am > I missing something? > > Does the attached patch work for you? I am also experiencing this problem, and the patch fixes it for me. David

1 0

Compiling GiNaC on OS X
by Stefan Schupp 23 Oct '13

23 Oct '13

Hi, I am trying to compile GiNaC under OS X with clang++ and the usage of libc++ (this is required, as my project, where I want to include GiNaC requires the c++11 standard). Therefore I added the following configuration options: ./configure CXX=/usr/bin/clang++ CXXFLAGS="-std=c++11 -stdlib=libc++" LDFLAGS="-stdlib=libc++" Upon invoking make I get an error regarding an ambiguous conversion in multiple lines: inifcns_nstdsums.cpp:2604:18: error: ambiguous conversion for functional-style cast from 'int' to 'lst' (aka 'container<std::list>') return e * (-H(lst(0),1/arg).hold()); ^~~~~ ./container.h:145:2: note: candidate constructor container(STLT const & s, bool discardable = false) ^ ./container.h:167:11: note: candidate constructor explicit container(const ex & p1) All errors are in the above file inifcns_nstdsums.cpp and occur with the same cast: H(lst(0),1/arg).hold() >From the error message I can conclude that there are two constructors applyable - which one is the correct one? E.g. casting 0 to ex (changing the line to: H(lst( ex(0) ),1/arg).hold() solves the error - is this the correct cast or is the other cast the correct one? Best Stefan

2 1

Re: [GiNaC-list] GiNaC-list Digest, Vol 93, Issue 4
by Gunnar Birke 30 Sep '13

30 Sep '13

On 26.09.2013 12:00, ginac-list-request(a)ginac.de wrote: > Send GiNaC-list mailing list submissions to > ginac-list(a)ginac.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://www.cebix.net/mailman/listinfo/ginac-list > or, via email, send a message with subject or body 'help' to > ginac-list-request(a)ginac.de > > You can reach the person managing the list at > ginac-list-owner(a)ginac.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of GiNaC-list digest..." > > > Today's Topics: > > 1. Re: user defined functions and constants (Vladimir V. Kisil) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 26 Sep 2013 09:34:40 +0100 > From: "Vladimir V. Kisil" <kisilv(a)maths.leeds.ac.uk> > To: GiNaC discussion list <ginac-list(a)ginac.de>, Gunnar Birke > <gunnar.birke(a)online.de> > Cc: "Vladimir V. Kisil" <kisilv(a)maths.leeds.ac.uk> > Subject: Re: [GiNaC-list] user defined functions and constants > Message-ID: <18176.1380184480(a)krein.leeds.ac.uk> > > Hi, > >>>>>> On Sat, 21 Sep 2013 20:07:12 +0200, Gunnar Birke <gunnar.birke(a)online.de> said: > GB> the map, then call subs() with it. Enable the same support for > GB> functions however seems very difficult, as functions can only > GB> defined at compile time with a macro. And using subs() seems a > GB> bit silly with functions: > > Unfortunately, I did not understand the difficulty which you were > talking about. May be you was mislead by name of GiNaC::function > class? For your example, you do not need o define f(x) and g(x,y) as > GiNaC::function. They may be happily defined as an GiNaC::ex containing > GiNaC::realsymbol x and y. I think, this will be sufficient for most of > your purposes. > > Best wishes, > Vladimir Well, my problem is that I don't understand how I turn an GiNaC::ex containing f(2) into an GiNaC::ex 2*3+2 in the case that f(x) is some GiNaC::ex 3*x + 2 where x is a symbol object. How do I tell GiNaC, that f(x) means 3*x+2 at runtime from the moment on the user defined f(x) in this manner. What I (think I) understood is that I can define functions with DECLARE_FUNCTION and REGISTER_FUNCTION at compile time and that I can have an expression GiNaC::ex f, which contains something like 3*x+2 where x is a symbol. So far so good, but how can I handle things like f(2)?

2 3