text: #include <cctype>
  #include <cmath>
  #include <cstdlib>
  #include <cstring>
  #include <fstream>
  #include <iostream>
  #include <sstream>
  #include <string>
  #include <unordered_map>
  #include <unordered_set>
  #include <vector>
  #include "utils.hpp"
  using namespace std;
  
  string print_term(const int &index);
  void parser(string str, vector<elementaryFunctionLib> &terms,
              vector<double> &coeff);
  vector<double> Range_vec(const string &range);
  int get_Mesh(const string &mesh);
  