Skip to content

usage.md

Latest commit

 

History

History
52 lines (44 loc) · 2.91 KB

usage.md

File metadata and controls

52 lines (44 loc) · 2.91 KB

Usage

GECo can be used either as a programmable Python library (see demos in the demo subdirectory) or via its graphical user interface (command 'geco').

The simplest way to get started is by using the demos located in geco/demos/.

Running the demos

Before running the demos you should complete the set-up steps indicated in the Installation.

To run the demos navigate to geco/demos/ and run for example

python3 ev_torus.py

The solution files are stored in geco/demos/solutions/ev/ by default, and this location can be customized by modifying the output.solution_directory parameter (for example solver.parameters["output"]["solution_directory"] = custom_solution_dir). For additional parameters see the SolverBase class.

The generated output files depend on whether the gravitational interaction is Newtonian or general relativistic. For the relativistic demo ev_torus and similar, GECo generates the following output files:

  • Gravitational fields NU, MU, BB, WW each in .xdmf and .xml.gz format
  • Spatial density RHO in .xdmf and .xml.gz format
  • Energy-momentum components P00, P03, P33, P11 in .xdmf and .xml.gz format.

For details on the meaning of these quantities see On Axisymmetric and Stationary Solutions of the Self-Gravitating Vlasov System

Postprocessing

Several postprocessing scripts are collected in geco/bin/. To run postprocessing on a solution, first navigate to the solution directory, before running

geco-postprocessing-data

if GECo is installed, or

python3 ~/geco/bin/geco-postprocessing-data

otherwise. This will run the postprocessing script to generate additional scalar data from the computed solution. Several of the postprocessing scripts rely on this data, so it is a good idea to run this script first. Other postprocessing scripts can be used similarly.

New Ansatz functions

GECo is a convenient tool for exploring solutions and their properties corresponding to new distribution ansatz functions. To write and use a new ansatz, the following steps should be taken:

  • Define your ansatz as a subclass of the EVAnsatz or VPAnsatz classes, as in geco/cppcode/EV-E-Polytropic-L-Polytropic.h. The ansatz should contain member functions ansatz, init_parameters, and read_parameters. The model must be defined in a file with the pattern cppcode/EV-[MY-MODEL-NAME].h or cppcode/VP-MY-MODEL-NAME].h as appropriate.
  • Add your ansatz to the list of PYBIND11_MODULES in either geco/cppcod/EVBindings.h or geco/cppcod/VPBindings.h, following the examples already present. Make sure to #include the header file corresponding to your new ansatz class. This provides Python bindings.
  • Finally use your model in a run_my_model.py file as in model = MaterialModel("MY_MODEL-NAME"). Reference existing demos for more complete information.