During week 11 I extended differential operator to handle mixed coordinate system.
Mixed means that
vector which we’re using as argument has elements coming from several different coordinate systems. Not necessarily connected.
These work were split into three PR’s, one for every differential operator,
To implement this, we need to only take care about product rule for
vector, but they are well defined.
Basically we didn’t change any behavior but now when we put expression likea = CoordSys3D('a') b = CoordSys3D('b', transformation='spherical') s = a.x*b.z gradient(s)
they are correctly interpreted.b.z*a.i + (a.x/(b.x*sin(b.y)))*b.k