I am resending this mail. This is a very critical issue for me. I absolutely must be able to change a string into an expression. And if I am doing it wrong, please show it to me. Thanks, Saurav Saurav Pathak [Mon, Jan 30, 2006 at 07:31:20PM -0500]: + 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