#include<bibli_fonctions.h>
#include<iostream>
#include<fstream>
using namespace std;

/* Lentilles simples */

double pos_image(double l, double f, double x){
  double xp;

  xp = 1./f + 1./(x-l);
  xp = l + 1./xp;
  return xp;
}

int main(){
  double u, F, d, f, y1, y2, g;
  int i, imax;
  fstream fich;

  f = 20.; d = 500.; F = 50.;
  imax = 1000;
  fich.open("lentilles_py.res", ios::out);
  for (i = 1; i <= imax; i++){
    u = (d/imax)*i;
    y1 = pos_image(u,F,0.);
    g = -(y1-u)/u;
    y2 = pos_image(d,f,y1);
    g = -g*(y2-d)/(d-y1);
    fich << u << " " << y2-d-f << " " << 10*g << endl;
  }
  fich.close();

  ostringstream pyth;
  pyth
    << "A = loadtxt('lentilles_py.res')\n"
    << "plot(A[:,0], A[:,1], label='y(u)')\n"
    << "plot(A[:,0], A[:,2], label='grandissement * 10')\n"
    << "plot(A[:,0], 0*ones(len(A[:,0])), label='0')\n"
    << "plot(A[:,0], 2*ones(len(A[:,0])), label='2')\n"
    << "ylim(-30,30)\n"
    << "xlabel('u')\n"
    << "legend(loc=9)\n" // mettre la legende en haut au milieu
    ;
  // On pourrait rajouter une ligne "help(legend)\n" pour voir les possibilites
  make_plot_py(pyth);

  return 0;
}