#include <fstream>
#include <math.h>
#include <iomanip>
#include <boost/numeric/ublas/vector.hpp>
#include <boost/numeric/ublas/io.hpp>

int main () {
  using namespace std;
  namespace ublas = boost::numeric::ublas;
  ublas:: vector<double> v(6);
  ublas:: vector<double> vv(v);
  ofstream outfile("data.dat"); 
  ifstream infile("data.dat"); 
  for (unsigned i=0; i<6; ++i) v(i)=sqrt(i);
  outfile.precision(16);  // accuracy for file output
  outfile<<v;  // write vector to file
  outfile.close();
  cout.precision(16); // accuracy for screen output
  cout<<"  to file: vector  v = "<<v<<endl;
  infile>>vv;  // read vector from file 
  infile.close();
  cout<<"from file: vector vv = "<<vv<<endl;
  return EXIT_SUCCESS;
}