params_pq.rst

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Parameters for Parameterized Quantities

Parameterized quantities are most often used in the context of the galaxy luminosity function, where model the efficiency of star formation as a function of halo mass and (perhaps) redshift. See the mirocha2017 option in :doc:`param_bundles` for a concrete example of how these parameters can be used. The basic idea is to provide a framework that enables any parameter to be parameterized more generally as a function of redshift, halo mass, etc. This potential is not yet fully realized, so beware that not all parameters can utilize this functionality!

A more detailed description of the methodology can be found here: :doc:`uth_pq`.

The relevant parameters are:

pq_func

Function adopted. Options include pl, dpl, and many more. See listing below parameter(s) pq_func_par[0-5].

Default: dpl

pq_func_var

Independent variable of pq_func.

Options:

• mass
• redshift

Default: mass

pq_func_par[0-5]

Parameters required by pq_func. Their meaning depends on the type of function employed. See below for meaning of each parameter by pq_func and number (x is either redshift or halo mass in general).

Options:

• pl: p[0] * (x / p[1])^{p[2]}
• dpl: p[0] / ((x / p[1])^{-p[2]} + (x / p[1])^{-p[3]})
• dpl_arbnorm: p[0](p[4]) / ((x / p[1])^-p[2] + (x / p[1])^-p[3])'
• pwpl: p[0] * (x / p[4])^{p[1]} if x \leq p[4] else p[2] * (x / p[4])^{p[3]}
• plexp: p[0] * (x / p[1])^{p[2]} * np.exp(-x / p[3])
• lognormal: p[0] * np.exp(-(logx - p[1])^2 / 2 / p[2]^2)
• astep: p[0] if x \leq p[1] else p[2]
• rstep: p[0] * p[2] if x \leq p[1] else p[2]
• plsum: p[0] * (x / p[1])^{p[2]} + p[3] * (x / p[4])^{p[5]}

Default: None

pq_func_var

Independent variable of pq_faux.

Options:

• mass
• redshift

Default: None