.. _physics-universeOperator:

Universe Operators
==================

Class providing operators that act on ``universe`` objects---top-level transformations applied to a fully-evolved Galacticus universe (containing the complete set of merger trees and their galaxies) prior to or after model evolution. Universe operators can perform global post-processing steps such as computing derived statistics, writing supplementary output, or modifying global properties. The interface provides a single ``operate`` method that receives the universe object and performs whatever transformation the implementation requires.

**Default implementation:** ``universeOperatorIdentity``

Methods
-------

``operate`` → ``void``
   Operate on the universe.

   * ``type(universe), intent(inout) :: universe_``

.. _physics-universeOperatorIdentity:

``universeOperatorIdentity``
----------------------------

An identity operator on universes.

**(Default implementation)**

**Parameters**

* ``[redshift]`` (default ``0.0d0``) — The redshift at which the transfer function is defined.

.. _physics-universeOperatorIntergalacticMediumStateEvolve:

``universeOperatorIntergalacticMediumStateEvolve``
--------------------------------------------------

An operator on universes which attaches hooks to compute evolution of the intergalactic medium.

**Methods**

* ``stateSet`` — Set the state of the IGM state class up to the given time index.

**Parameters**

* ``[timeCountPerDecade]`` (default ``10``) — The number of bins per decade of time to use for calculations of the properties of the universe.
* ``[redshiftMinimum]`` (default ``0.0d0``) — The minimum redshift to use in calculations.
* ``[redshiftMaximum]`` (default ``400.0d0``) — The maximum redshift to use in calculations.