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;
;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 from the centre
;of the cube. 
;
;The parameter v_rot (in makeIC.py and cooling.yml) sets the circular velocity
;of the halo, and by extension, the viral radius, viral mass, and the 
;internal energy of the gas such that hydrostatic equilibrium is achieved.
;
;The gas is given some angular momentum about the z-axis. This is defined by
;the 'spin_lambda' variable in makeIC.py
;
;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.
;
;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.
;
;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.
;
;