[GiNaC-list] symbol equality

[Marko Riedel]

Greetings to all.

I have been subclassing "symbol" for my project, where I need to attach 
an integer value to a symbol. I am not sure this is the best way to go 
about it but I would like to try. Everything works so far but now I have 
moved on to substituting variables in polynomials. Here is my sample 
program.

#include <iostream>
#include <ginac/ginac.h>

#include "cindsymbol.h"
#include "util.h"

using namespace std;
using namespace GiNaC;


int main()
{
   cindsymbol R = cindsymbol("R",0), G = cindsymbol("G",0),
     B = cindsymbol("B",0), X = cindsymbol("X",0);

   ex pl = X + pow(X, 3) + R + G + B;

   cout << R << G << B << " " << pl << endl;
   cout << pl.subs({X}, {pow(X,4)}) << endl;

   return 0;
}

The output of this program is as follows (the print functions from the 
subclass are being invoked correctly and do not print the zero value):

RGB X+R+G+B+X^3
4*X^4+X^12

Obviously GiNaC thinks that R=X, B=X and G=X. How do I get this 
comparison to work? Do I need to override some function in my subclass?
The function "cindsymbol" goes as follows (copied from the tutorial):

static map<string, cindsymbol> directory;

cindsymbol cindsym(const std::string & initname,
                    unsigned cl)
{
   std::string key = initname + "|" + std::to_string(cl);
   map<std::string, cindsymbol>::iterator it = directory.find(key);

   if (it != directory.end())
     return it->second;
   else{
     std::pair<std::string, cindsymbol> ent =
       make_pair(key, cindsymbol(initname, cl));
     return directory.insert(ent).first->second;
   }
}

Can you advise me here? Thanks!

Best regards,

Marko Riedel