Hi, there still seems a problem left - after unarchiving, substituting doesn't work anymore with realsymbols, while it works with symbols. I augmented the testcase, which now is #include <iostream> #include <fstream> #include <stdexcept> using namespace std; #include <ginac/ginac.h> using namespace GiNaC; int main() { archive aro, ari; realsymbol r("r"); symbol s("s"); ex test, test2; test = r+s; cerr << "writing archive\n"; ofstream aus("test.gar"); aro.archive_ex(test, "test"); aus << aro; aus.close(); cerr << "done writing archive\n"; cerr << "reading archive\n"; ifstream ein("test.gar"); ein >> ari; ein.close(); cerr << "done reading archive\n"; lst symlst; symlst = r,s; cerr << "unarchiving\n"; try { test2 = ari.unarchive_ex(symlst); } catch (std::exception &e) { cerr << e.what() << std::endl; } cerr << "recovered expression\n\n"; cerr << "expression = " << test2 << "\n"; test = test2.subs(lst(r==0,s==0)); cerr << "substituting (r=0,s=0) = " << test << "\n"; return 0; } Thanks! ___________________________________________________________ GRATIS! Movie-FLAT mit über 300 Videos. Jetzt freischalten unter http://movieflat.web.de