We previously used bool() on the constraints expression to find
out whether we need to use the DIrichletConstraintsAssembler.
However, UFL does the stupid thing of evaulating

bool(eq(x[0], 0))

to False, because x[0] and 0 are obvioulsy not the same. Veeeery
bad behaviour for a symbolic language.

We do this from multiple subdirs

Calculate the evaluation and jacobians of geometry mappings of cells
using sum factorization. By avoiding all geometry mapping of intersections
we can avoid the face-twist problem and just make the grid consistens (not
yet done).

TODO:
- Make grid consistent
- Vectorization
- 3D

Not yet implemented:

- Vectorization of quadrature loop
- Anisotropic amount of quadrature points per direction

René Heß authored 6 years ago and Dominic Kempf committed 6 years ago

Rename the function and remove the backend switch. Reasoning:

- This function was only called once without the backend switching
  mechanism.
- The function takes different arguments than the pdelab
  pymbolic_quadrature_position.
- It returns only one component of the quadrature point.

René Heß authored 6 years ago and Dominic Kempf committed 6 years ago

Probably not the solution we want to have in the long run but right
now it is not possible to have a backend switch for
default/blockstructured/sumfact. This way the old code should behave
the same way as before and it is possible to switch between those
three things.