updates after 2012.3

Hi,

this is to inform you about the latest updates of the code.

1. The 'hierarchic' branch has been merged into the master. This branch introduces a hierarchical FE basis into the code and some other tools described below. Look at [1] for an example. It's not finished, but I have decided to merge it already, as the general ideas seem to be work, and I needed some of the developments in the master and vice-versa. The caveats are for now:

• Only 2_4 (rectangles) and 3_8 (bricks) elements are supported.
• Dirichlet boundary conditions are piece-wise linear - the higher order boundary dofs are set to zero. To allow them, projections to FE spaces on a region would have to be implemented. We are thinking about redesigning the C FE core to make tasks such as this easier.
• Surface integral terms are not yet supported.
• The post-processing is more difficult, as a linearization of the solution is required.
• A test was written that checks the basis continuity between two elements. This test revealed that the standard nodal basis on 3_8 elements has wrong face orientations (the functions from the two face sides do not match) for approximation order >= 3. This will be fixed, hopefully before the next release.

2. New plotting modules / updated scripts:

• script/save_basis.py can be used to visualize a FE basis or its gradient on a single element or on a (small) mesh.
• New modules sfepy/postprocess/plot_facets.py and sfepy/postprocess/plot_dofs.py can be used to plot the reference elements and DOF numberings. Matplotlib with mplot3d is needed there.

r. [1] http://docs.sfepy.org/doc-devel/examples/diffusion/sinbc.html