Thanks. I did not know about PDEtools:-Infinitesimals
You said "Basically all the symmetry commands in (O)DEtools have an equivalent in PDEtools. For symgen, the equivalent is Infinitesimals"
Do you suggest then to use PDEtools:-Infinitesimals instead of DEtools:-symgen for find the symmetries?
I Just did quick test (without knowing too much about all the other options for PDEtools:-Infinitesimals since I never used it before), I noticed for some cases, symgen gives result, where PDEtools:-Infinitesimals seems to hang. For example
just says "evaluating....". I waited for long 5 minutes and nothing happened. May be I need to look at the other options to see why this happened and figure what is going on...
ps. I do not understand this line in the help page for ?PDEtools:-Infinitesimals
where it says
"PDESYS- PDE or a set or list of PDEs; it can include ODEs and not differential equations"
What is the difference between ODEs and differential equations in the above?