Add access to more geometry quantities through ufl

[Martin Sandve Alnæs]

Done:

• Adding expression types

Todo:

• Updating algorithms in UFL
• Updating algorithms in form compilers
• Generating code in form compilers
• Eventual convenience updates in PyDOLFIN

[Martin Sandve Alnæs]

I've added some types and here's the full list now:

        SpatialCoordinate
        LocalCoordinate (where applicable)

        Jacobian (currently affine but should represent non-affine later)
        JacobianDeterminant
        JacobianInverse ((pseudo-)inverse of Jacobian)

        FacetJacobian (currently affine but should represent non-affine later)
        FacetJacobianDeterminant
        FacetJacobianInverse ((pseudo-)inverse of Jacobian)

        CellVolume
        Circumradius

        FacetArea
        MinFacetEdgeLength
        MaxFacetEdgeLength

        FacetNormal

Just need to get all into ffc.

[Anders Logg (Chalmers)]

Where are these documented/listed (except for on this page)?

[Martin Sandve Alnæs]

Listed in ufl docstring, but the documentation is not good enough.

[Martin Sandve Alnæs]

Anyone need CellSurfaceArea and FacetDiameter? They're not implemented in ffc, I think I might remove them from ufl.

[Martin Sandve Alnæs]

Jacobian* are maybe not well defined? In cell integrals all is fine but for exterior and interior facet integrals maybe we need to have CellJacobian vs FacetJacobian.

[Martin Sandve Alnæs]

Good progress, won't be completed for 1.4.

[Martin Sandve Alnæs]

The names above are not the final ones. I've tried to at least improve the docstrings of the new types, although there's still room for better documentation.

[Martin Sandve Alnæs]

Closing this because it's too broad. A bunch of such quantities are now available when using uflacs, and the full pipeline is tested in a dolfin unit test. I have no intention of making all available in vanilla ffc. Create a new issue if anything in particular is needed.

[Martin Sandve Alnæs]

Removing milestone: 1.7 (automated comment)