Hi all,
I have been recently trying to simplify some vector calculus and
although vect.mac is very good generally, it is giving me incorrect
answers on a type of calculation. I wonder if this is the lack of
experience showing on my part or a genuine error? - any help with this
would be appreciated...
PROBLEM: (assume vect package is loaded)
declare([u,v],nonscalar);
declare(phi,scalar);
ev(vectorsimp(grad(phi*v)),expandall:true);
ANS:
grad(phi*div(v)) + grad(grad(phi).v)
which is exactly a "grad" off the mark...
Cheers
Jack