.. _physics-unevolvedSubhaloMassFunction:

Unevolved Subhalo Mass Function
===============================

Class providing unevolved subhalo mass functions :math:`\mathrm{d}N/\mathrm{d}m`---the mass spectrum of subhalos at the time they first fell into their host, before tidal stripping has reduced their mass. The unevolved subhalo mass function represents the initial conditions for subhalo evolution and is predicted from the extended Press-Schechter formalism or calibrated to N-body simulations. Both differential (per unit mass per host halo) and integrated (between two mass limits) forms are provided, as functions of the subhalo mass, host mass, and cosmic time.

**Default implementation:** ``unevolvedSubhaloMassFunctionGiocoli2008``

Methods
-------

``differential`` → ``double precision``
   Return the differential unevolved subhalo mass function per halo for ``mass`` [:math:`\mathrm{M}_\odot`] subhalos in ``massHost`` [:math:`\mathrm{M}_\odot`] hosts at ``time`` [Gyr].

   * ``double precision, intent(in ) :: time, mass, massHost``

``integrated`` → ``double precision``
   Return the unevolved subhalo mass function per host at ``time`` [Gyr] in hosts of mass ``massHost`` [:math:`\mathrm{M}_\odot`] integrated between ``massLow`` and ``massHigh`` [:math:`\mathrm{M}_\odot`].

   * ``double precision, intent(in ) :: time, massLow, massHigh, massHost``

.. _physics-unevolvedSubhaloMassFunctionGiocoli2008:

``unevolvedSubhaloMassFunctionGiocoli2008``
-------------------------------------------

The halo mass function is computed from the function given by :cite:t:`giocoli_population_2008`.

**(Default implementation)**

**Parameters**

* ``[normalization]`` (default ``0.21d0``) — The parameter :math:`N_0` in the :cite:t:`giocoli_population_2008` unevolved subhalo mass function fit.
* ``[exponent]`` (default ``0.8d0``) — The parameter :math:`\alpha` in the :cite:t:`giocoli_population_2008` unevolved subhalo mass function fit.