FakeSim

class halotools.sim_manager.FakeSim(num_massbins=10, num_halos_per_massbin=100, num_ptcl=20000, seed=43, redshift=0.0, cosmology=FlatLambdaCDM(name="WMAP5", H0=70.2 km / (Mpc s), Om0=0.277, Tcmb0=2.725 K, Neff=3.04, m_nu=[ 0. 0. 0.] eV, Ob0=0.0459), **kwargs)[source] [edit on github]

Bases: halotools.sim_manager.UserSuppliedHaloCatalog

Fake simulation data used in the test suite of empirical_models.

The FakeSim object has all the attributes required by Mock Factories such as HodMockFactory to create a mock galaxy population. The columns of the halo_table and ptcl_table attributes of FakeSim are generated with np.random. Thus mock catalogs built into FakeSim will not have physically realistic spatial distributions, mass functions, etc. All the same, FakeSim is quite useful for testing purposes, as it permits the testing of sim_manager and empirical_models to be completely decoupled. Default behavior is to use a fixed seed in the random number generation, so that an identical instance of FakeSim is created for calls with the same arguments.

Parameters:

num_massbins : int, optional

Number of distinct masses that will appear in the halo catalog. Default is 6.

num_halos_per_massbin : int, optional

Default is 1000

num_ptcl : int, optional

Number of dark matter particles. Default is 1000.

seed : int, optional

Random number seed used to generate the fake halos and particles. Default is 43.

cosmology : astropy.cosmology instance, optional

Default is halotools.sim_manager.sim_defaults.default_cosmology.

Examples

>>> halocat = FakeSim()