OK, is not so difficult,
first go in directory src of the distribution
after find '“convert” in all source files
brochet:src hecht$ grep '"convect"' */*pp
fflib/lgfem.cpp: Global.Add("convect", "(", new OneOperatorCode< Convect >);
brochet:src hecht$
after find the word ‘Convect’
brochet:src hecht$ grep -n 'Convect' */*pp
fflib/lgfem.cpp:2261:class Convect : public E_F0mps {
fflib/lgfem.cpp:2269: Convect(const basicAC_F0 &args) : u(0), v(0), w(0), ff(0), dt(0) {
fflib/lgfem.cpp:2290: if (verbosity > 3) cout << "\n -- Convert number of Convect case: .... " << state << endl;
fflib/lgfem.cpp:2301: static E_F0 *f(const basicAC_F0 &args) { return new Convect(args); }
fflib/lgfem.cpp:2308:Expression Convect::ou = 0;
fflib/lgfem.cpp:2309:Expression Convect::ov = 0;
fflib/lgfem.cpp:2310:Expression Convect::ow = 0;
fflib/lgfem.cpp:2311:Expression Convect::odt = 0;
fflib/lgfem.cpp:2312:long Convect::count = 0;
fflib/lgfem.cpp:5064:AnyType Convect::operator( )(Stack s) const {
fflib/lgfem.cpp:5071:AnyType Convect::eval2(Stack s) const {
fflib/lgfem.cpp:5117: cerr << "Fatal error in Convect (R2) operator: loop => velocity too high ???? or NaN "
fflib/lgfem.cpp:5144:AnyType Convect::eval3old(Stack s) const {
fflib/lgfem.cpp:5146: if (newconvect3) return eval3(s); // New Convect in test
fflib/lgfem.cpp:5228:AnyType Convect::eval3(
fflib/lgfem.cpp:6264: Global.Add("convect", "(", new OneOperatorCode< Convect >);
the function convect is defined in at
fflib/lgfem.cpp:5064:AnyType Convect::operator( )(Stack s) const
good luck