_ROOT Version:_6.14/06
Platform: MAC OS MOJAVE
Compiler: g++
I am trying to run a code which does minimization using TMinuit in a .cpp file. Whenever I run the .C version of the same code in the root interpreter it works fine but whenever I compile it the usual C++ way of using g++ along with ROOT libraries I get the following error:
Undefined symbols for architecture x86_64:
"TMinuit::SetFCN(void (*)(int&, double*, double&, double*, int))", referenced from:
_main in min-c0bfd0.o
"TMinuit::mnexcm(char const*, double*, int, int&)", referenced from:
_main in min-c0bfd0.o
"TMinuit::mnparm(int, TString, double, double, double, double, int&)", referenced from:
_main in min-c0bfd0.o
"TMinuit::mnstat(double&, double&, double&, int&, int&, int&)", referenced from:
_main in min-c0bfd0.o
"TMinuit::TMinuit(int)", referenced from:
_main in min-c0bfd0.o
"TMinuit::~TMinuit()", referenced from:
_main in min-c0bfd0.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
This is how I am compiling my code:
g++ -o min min.cpp quadratic.cpp -I$ROOTSYS/include -L$ROOTSYS/lib `root-config --cflags --glibs`
My original source file looks like:
#include <iostream>
#include <fstream>
#include <vector>
#include "quadratic.h"
#include "quadratic.cpp"
// #include <TMinuit.h>
#include <TFile.h>
#include <TMinuit.h>
#include <TApplication.h>
#include <TROOT.h>
using namespace std;
#define N_BINS 500
static QuadraticFunc poly;
static QuadraticFunc *polyPtr;
std::vector<double> bin_center;
std::vector<double> bin_content;
std::vector<double> bin_error;
// Function for calculating chi-square.
double poly_integral = 3 / 4.;
void chi2_fn(int &npar, double *gin, double &f, double *par, int iflag)
{
double delta = 0;
double chi_square = 0;
double t;
poly.params.a = par[0];
poly.params.b = par[1];
poly.params.c = par[2];
for (int i = 5; i < (N_BINS - 5); ++i)
{
t = bin_center[i];
delta = (bin_content[i] - poly_integral * (poly.params.a * t * t + poly.params.b * t + poly.params.c)) /
bin_error[i];
chi_square += delta * delta;
}
f = chi_square;
}
int main()
{
double bin_center_hold;
double bin_content_hold;
double bin_error_hold;
ifstream fin("quad_hist_features.dat");
while (fin >> bin_center_hold >> bin_content_hold >> bin_error_hold)
{
bin_center.push_back(bin_center_hold);
bin_content.push_back(bin_content_hold);
bin_error.push_back(bin_error_hold);
}
double arglist[10];
int ierflg = 0;
TMinuit minuit(3);
minuit.SetFCN(chi2_fn);
arglist[0] = 2.30;
minuit.mnparm(0, "a", -1.0, 0.1, 0, 0, ierflg);
minuit.mnparm(1, "b", 2.0, 0.1, 0, 0, ierflg);
minuit.mnparm(2, "c", 0.0, 0.1, 0, 0, ierflg);
minuit.mnexcm("MIGRAD", arglist, 0, ierflg);
minuit.mnexcm("MINOS", arglist, 0, ierflg);
double fmin, fedm;
double errdef;
int nparv, nparx;
int fstat;
minuit.mnstat(fmin, fedm, errdef, nparv, nparx, fstat);
cout << "\n\n";
cout << "Results of MINUIT minimisation\n";
cout << "-------------------------------------\n\n";
cout << " Minimal function value: " << fmin << endl;
cout << " Estimated difference to true minimum: " << fedm << endl;
cout << " Number of parameters: " << nparv << endl;
cout << " Error definition (Fmin + Delta): " << errdef << endl;
if (fstat == 3)
{
cout << " Exact covariance matrix." << endl;
}
else
{
cout << " No/error with covariance matrix." << endl;
cout << " Error code: " << fstat << endl;
}
}
This code is basically fitting a quadratic polynomial through a set of data points.
Also, .I built root with cmake. I tried compiling this code with cmake as well but still getting the same error
