The following example is contained in :download:`example.py`. It reads in a MUSIC-generated initial conditions at first order; calculates the second-order initial displacements on the full box; then runs COLA and finally outputs a figure containing a density slice. The script needs matplotlib to be installed.
To run the script, first generate MUSIC initial conditions with the included configuration file:
MUSIC ics.conf
Then change the variable music_file below to point to the MUSIC
snapshot, and then execute the example script by issuing:
python ./example.py
This example script was used with minor modifications in making the
figures for the paper. It fits comfortably on 24GB ram. If that is not
available, decreasing gridscale to 1, reduces ram consumption to
11GB at the cost of reducing force resolution and producing artifacts.
Most of the time, the script spends on calculating the second-order displacement field for the whole box, i.e. not on the COLA calculation. On the 4-core laptop the calculations for the paper were performed, the COLA calculation itself takes about 40 seconds.
The script produces the following figure:
.. literalinclude:: example.py :lines: 25-
.. automodule:: example