Implement sp.Sum, sp.Product
Sum and Product have a indexing variable which is a Atom but not a free
symbol. So logic, that defines the undefined symbols in a SympyAssignment
should not be
atoms(sp.Symbol)
but free_symbols
. sp.Indexed
from the ResolvedFieldAcess
es forms an edge case.
So we could also use atoms(sp.Symbol).intersection(...free_symbols)
.
I hope I extracted from my fork all the necessary code to implement this feature.
Edited by Stephan Seitz