mat B;

  // endr indicates "end of row"
  B << 0.555950 << 0.274690 << 0.540605 << 0.798938 << endr
    << 0.108929 << 0.830123 << 0.891726 << 0.895283 << endr
    << 0.948014 << 0.973234 << 0.216504 << 0.883152 << endr
    << 0.023787 << 0.675382 << 0.231751 << 0.450332 << endr;

  // print to the cout stream
  // with an optional string before the contents of the matrix
  B.print("B:");

  // the << operator can also be used to print the matrix
  // to an arbitrary stream (cout in this case)
  cout << "B:" << endl << B << endl;
  // save to disk
  B.save("B.txt", raw_ascii);
  // load from disk
  mat C;
  C.load("B.txt");
  C += 2.0 * B;
  C.print("C:");