hi, i am having trouble turning a string with function "pow" into an expression. an example of the code is given below along with the output. i cannot figure out what i am doing wrong. thanks for your help in advance. -------- #include <iostream> #include <string> #include <ginac/ginac.h> #include <ginac/power.h> using namespace std; using namespace GiNaC; int main() { lst all; all.append(symbol("x")); // no pow string str2 = "x*x"; ex e2(str2, all); cout << "nopow : " << e2 << endl; // with pow string str = "pow(x, 2)"; ex e(str, all); cout << "withpow: " << e << endl; return 0; } the output is: nopow : x^2 terminate called after throwing an instance of 'std::runtime_error' what(): no function 'pow' with 2 parameters defined Aborted -------------------- -- saurav