Sample Flat Test - cmyoo/cosmos GitHub Wiki

Description of the very first test

• This is the simplest test for COSMOS code, which calculates the "time evolution" in the flat spacetime.

• Since all variables should keep its initial values, the simplest test will basically be passed when you observe "no evolution" around the machine precision in the final output.

Grid structure

To directly see the grid structure in the COSMOS simulation one can choose, there are three demos, flat_simplest, flat_simplest_scaleup, and flat_simplest_fmr.

• As other sample demos, it is possible to start the project by running the shell script ./makecosmos.sh or sh ./makecosmos.sh in the top of COSMOS directory (See Getting started).

  • flat_simplest

    • This sets up the simplest Cartesian grid structure $(x,y,z)$.
    • After running make and ./cosmos in this directory, you will find out_3d.dat in the same directory.
    • To check the simplest grid in the three dimensional box, you can run the gnuplot script inside gnuplot as load "show.gpl".

    

  • flat_simplest_scaleup

    • This allows us to use more finer grid around the origin $(0,0,0)$.
    • After running make and ./cosmos in this directory, you will find out_3d.dat in the same directory.
    • To check the scale-up grid in the three dimensional box, you can run the gnuplot script inside gnuplot as load "show.gpl".

    

  • flat_simplest_fmr

    • This further enables us to calculate with higher resolution around the origin $(0,0,0)$ using Fixed Mesh Refinement.
    • After running make and ./cosmos in this directory, you will find out_3d0.dat and out_3d1.dat for two layers' data in the same directory.
    • To check the FMR grid in the three dimensional box, you can run the gnuplot script inside gnuplot as load "show.gpl".