Commit 8a57ddb0 authored by James Willis's avatar James Willis
Browse files

Small updates to README for generating videos from snapshots.

parent 2474a3c2
Initial Conditions Generation
-----------------------------
To make the initial conditions we distribute gas particles randomly in
a cube with a side length twice that of the virial radius. The density
profile of the gas is proportional to r^(-2) where r is the distance
......@@ -16,14 +17,31 @@ While the system is initially in hydrostatic equilibrium, the cooling
of the gas and the non-zero angular momentum means that the halo will
collapse into a spinning disc.
Compilation
-----------
To run this example, make such that the code is compiled with either
the isothermal potential or softened isothermal potential, and
'const_lambda' cooling, set in src/const.h. In the latter case, a
(small) value of epsilon needs to be set in cooling.yml. 0.1 kpc
should work well.
Checking Results
----------------
The plotting scripts produce a plot of the density, internal energy
and radial velocity profile for each
snapshot. test_energy_conservation.py shows the evolution of energy
with time. These can be used to check if the example has run properly.
Generating Video
----------------
If you want to generate a video of the simulation, the frequency of
the snaphots needs to be increased. This can be modified in cooling.yml
by changing 'delta_time' to 0.01.
Once you have the snapshots, 'gadgetviewer' can be used to create a
series of snapshot frames. The frames can then be combined together with
'ffmpeg' to produce a video. The following command can be used:
ffmpeg -r 20 -i frame_%05d.image.png -c:v ffv1 -qscale:v 0 movie.avi
to produce the video.
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