Clean up and Bug Fixes

Fixes #38 (closed)

Further changes:

• Third party warnings are suppressed now as they just polluted the warning summary in pystencils.
• Removing the math optimisations as they are not used in pystencils. An Issue is created to reintroduce them again in a clean way in the future
• Removing the joblib workaround as joblib is a hard dependency of pystencils
• Fixing SymPy 1.9 as maximum version
• Removing sympy.multiply_elementwise due to https://github.com/sympy/sympy/issues/22353. A workaround with NumPy is introduced which seems to be way more robust because NumPy has a more static API
• Introducing more extra requires, which are needed to have all features of pystencils
• Minor cleanup of some test cases and the datahandling

pystencils/fd/derivation.py

@@ -261,7 +261,7 @@ class FiniteDifferenceStaggeredStencilDerivation:
             main_points = [neighbor / 2, neighbor / -2, flipped(neighbor / 2, nonzero_indices[0]),
                            flipped(neighbor / -2, nonzero_indices[0])]
         else:
-            main_points = [neighbor.multiply_elementwise(sp.Matrix(c) / 2)
+            main_points = [sp.Matrix(np.multiply(neighbor, sp.Matrix(c) / 2))
                            for c in itertools.product([-1, 1], repeat=3)]
         points += main_points
         zero_indices = [i for i, v in enumerate(neighbor) if v == 0 and i < dim]