[Voulet]

Hello. I didn't find any relevant post while googling this thus for future generation here is how to output some values in scientific notation. The key here is the following line :

mySuperStream.setf(ios_base::scientific, ios_base::floatfield);

// near your CreateField outside main loops
OFstream mySuperStream((string("Coucou")));
mySuperStream.precision(5);
mySuperStream.setf(ios_base::scientific, ios_base::floatfield);

mySuperStream   << "Time" << tab
                << "sumMatter" << tab
                << "Pthermique" << tab
                << "diff_pression"<< tab
                << "Joth"<< tab
                << endl;

// inside your loop
if (Pstream::master()) {
    mySuperStream <<    U.db().time().value() << tab
                            << sumMatter << tab
                            << Pthermique << tab
                            << diff_pression << tab
                            << Joth << tab
                            << endl;
 }

Happy foaming.