     GeomParameters gp_;
     Psip psip_;
 };
+
 /**
  * @brief Computes the background gradient for the densities
  */ 


#include <iostream>
#include <fstream>
#include <cmath>
#include <vector>
//6 analytical quantities
namespace dg

//             yp[1][i] = -y[0][i]*psipR_(y[0][i],y[1][i],y[2][i])/ipol_(y[0][i],y[1][i],y[2][i]) ;             //dZ/dphi = -R/I Psip_Z
//             yp[2][i] =  y[0][i]*y[0][i]/invB_(y[0][i],y[1][i],y[2][i])/ipol_(y[0][i],y[1][i],y[2][i]);       //ds/dphi =  R^2 B/I
            yp[2][i] =  y[0][i]*y[0][i]/invB_(y[0][i],y[1][i])/ipol_(y[0][i],y[1][i]);       //ds/dphi =  R^2 B/I
            yp[0][i] = y[0][i]*psipZ_(y[0][i],y[1][i])/ipol_(y[0][i],y[1][i]);              //dR/dphi =  R/I Psip_Z
            yp[1][i] = -y[0][i]*psipR_(y[0][i],y[1][i])/ipol_(y[0][i],y[1][i]) ;             //dZ/dphi = -R/I Psip_Z
        }
    }
