#define PI 3.14159
#define eps 1.e-10

double lorentzianPeak(double x[], double par[]){

  double Den = (x[0]-par[2])*(x[0]-par[2]) + par[1]*par[1]/4.;
  if ( Den < eps ) Den = eps;
  return ( par[0]*par[1]/(2.*PI) )/ Den;

}