Commit 8a57ddb0 authored by James Willis's avatar James Willis
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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 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 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 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 ...@@ -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 of the gas and the non-zero angular momentum means that the halo will
collapse into a spinning disc. collapse into a spinning disc.
Compilation
-----------
To run this example, make such that the code is compiled with either To run this example, make such that the code is compiled with either
the isothermal potential or softened isothermal potential, and the isothermal potential or softened isothermal potential, and
'const_lambda' cooling, set in src/const.h. In the latter case, a '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 (small) value of epsilon needs to be set in cooling.yml. 0.1 kpc
should work well. should work well.
Checking Results
----------------
The plotting scripts produce a plot of the density, internal energy The plotting scripts produce a plot of the density, internal energy
and radial velocity profile for each and radial velocity profile for each
snapshot. test_energy_conservation.py shows the evolution of energy snapshot. test_energy_conservation.py shows the evolution of energy
with time. These can be used to check if the example has run properly. 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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