SymPy made a backwards-incompatible change to how free_symbols works for Indexed expressions. See sympy/sympy#13360.
Currently, on Travis and AppVeyor, we enforce SymPy < 1.2 to avoid this problem. We should remove this restriction by investigating what the consequences SymPy's change are for QNET, and whether we need additional tests. Anything that relies on free_symbols needs to be checked carefully -- especially derivatives.
Tests should be written in such a way that they pass both for SymPy < 1.2 and SymPy >= 1.2.
SymPy made a backwards-incompatible change to how
free_symbolsworks forIndexedexpressions. See sympy/sympy#13360.Currently, on Travis and AppVeyor, we enforce SymPy < 1.2 to avoid this problem. We should remove this restriction by investigating what the consequences SymPy's change are for QNET, and whether we need additional tests. Anything that relies on
free_symbolsneeds to be checked carefully -- especially derivatives.Tests should be written in such a way that they pass both for SymPy < 1.2 and SymPy >= 1.2.