Yt

This Webpage is the wiki for developing the yt http://yt-project.org frontend for the Einstein Toolkit.

Status

We have an almost working frontend.

Challenges

• yt supports cell-centred data only.
  • To correct this we first implement a fake subgrid, filled by restriction
  • Later Matt will add better support for true vertex-centred data
• Multiblock is not yet supported, but yt's coordinate handler will be able to make it work.
• Discontinuous Galerkin methods are not supported. Support will come with hexahedral mesh support
  • High-order finite element support is coming and then discontinuous Galerkin methods will work beautifully.

Tasks in Order of Priority

Check off when done:

• handle unigrid data
• handle vertex-centred AMR data
• improve handling of boundaries (outer boundaries vs. symmetry boundaries)
• handle multi-block data
• handle cell-centred data
• remove buffer zones from output
• handle DGFE data
• measure performance, complain about performance problems

Also:

• collect (here on this wiki?) a list of additional information necessary, e.g. additional attributes that would be helpful
• suggest improvements to output format, from experience with other output formats

Shopping List

• information (best would be starting index and size) about what we call Active Region, i.e. part of the grid that's unique and not overlapping with its siblings (grids on the same level)
• full information about type of external boundaries, best would be 6 element integer array, or 3x2

Simulation List

We have the following simulations available to test against

• static_tov, a static neutron star with fixed mesh refinement
• ml_wavetoy, a series of simulations of a Gaussian pulse with refinement at the centre and periodic boundary conditions
• excited_tov_Lev0-i0000, a perturbed neutron star with adaptive mesh refinement and a sevenpatch multiblock infrastructure.
• bssn_dg4_sixpatches_kerrschild, a black hole with excision using discontinuous Galerkin methods

TODO

• After it is working, Jonah will add comments to the frontend to ensure future generations have the knowledge of Carpet required to design it gleaned during the workshop at the NCSA.
• Other TODOS?