template <class Tdouble> Tdouble myfunF ( Tdouble t, Tdouble *tis, int nbti)
{
  Tdouble res = 0.;
  double ri = 0.;
  for(int id=0;i<nbti;++i)
  {
    ri = ...;
    if (t>ti){
      res = res + ri;
    }
  }
  return res ;
}