add: out.precision(PRECISION);
context: main(int argc, char* argv[]){  interface inter;  try{  inter = interface("gs_l", argc, argv);  }  catch(invalid_argument e){    cerr << e.what() << endl;    return 1;  }  catch(help_exception){ return 0; }  catch(...){    cerr << "something bad happened!" << endl;    return 1;  }  laplace lp(inter.I(), inter.J(), inter.x(), inter.y(),	     inter.top(), inter.right(), inter.bottom(), inter.left());  int I,J;  int i,j;  double norm0;  ostream& out = cout;  I = lp.I();  J = lp.J();  double x0 = lp.x0();  double y0 = lp.y0();  double dx = lp.dx();  double dy = lp.dy();  for(i = 1; i < I; i++)    for(j = 1; j < J; j++)      lp.u(i,j) = (x0 + (i*dx));  norm0 = solution_norm_cyl::norm(lp);  out.precision(PRECISION);  out << "# norm:\t" << norm0 << endl;    if(!inter.header())    out << lp;}