.. _physics-metaTreeProcessingTime:

Merger Tree Processing Times
============================

Class providing estimates of the computational processing time required for merger trees---predictions of how long (in wall-clock time) it will take to evolve a merger tree of a given root halo mass, and of the remaining time for a partially-processed tree. These estimates are used by the work-sharing scheduler to balance computational load across MPI processes: trees expected to take longer can be started earlier or assigned to dedicated workers. The null implementation returns a negative value indicating that no estimate is available.

**Default implementation:** ``metaTreeProcessingTimeNull``

Methods
-------

``time`` → ``double precision``
   Return an estimate of the time needed to process a tree of the given mass.

   * ``double precision, intent(in ) :: massTree``

``timeRemaining`` → ``double precision``
   Return an estimate of the remaining time needed to process a given tree.

   * ``type(mergerTree), intent(inout) :: tree``

   * ``double precision, intent(in ) :: timeFinal``

.. _physics-metaTreeProcessingTimeFile:

``metaTreeProcessingTimeFile``
------------------------------

A merger tree processing time class which estimates processing times using a polynomial relation read from file. Specifically, the time taken to process a tree is estimate to be

.. math::

   \log_{10} [ \tau_\mathrm{tree}(M)] = \sum_{i=0}^2 C_i (\log_{10} M)^i,

where :math:`M` is the root mass of the tree and the coefficients :math:`C_i` are read from a file, the name of which is specified via the ``[fileName]`` parameter. This file should be an XML document with the structure:

.. code-block:: none

   <timing>
    <fit>
      <coefficient>-0.73</coefficient>
      <coefficient>-0.20</coefficient>
      <coefficient>0.03</coefficient>
    </fit>
   </timing>

where the array of coefficients give the values :math:`C_0`, :math:`C_1` and :math:`C_2`.

**Methods**

* ``readFile`` — Read the named power spectrum file.

**Parameters**

* ``[forceZeroMetallicity]`` (default ``.false.``) — Force the use of zero metallicity (or lowest metallicity available) for all stellar populations.
* ``[fileName]`` — The path to the HDF5 file containing the tabulated stellar population spectra, with datasets for ages (Gyr), metallicities (log Solar), wavelengths (\AA), and spectra (:math:`L_\odot\,\mathrm{Hz}^{-1}`); see the ``scripts/ssps`` folder for conversion scripts.
* ``[fileName]`` — The name of the file which contains fit coefficients for the time per tree fitting function.
* ``[fileName]`` (default ``inputPath(pathTypeDataStatic)//'stellarAstrophysics/stellarPropertiesCompilationStandard.xml'``) — The name of the XML file from which to read stellar properties (ejected masses, yields, etc.).
* ``[fileName]`` (default ``inputPath(pathTypeDataStatic)//'stellarAstrophysics/Stellar_Tracks_Padova.hdf5'``) — The name of the HDF5 file from which to read stellar tracks.
* ``[fileName]`` — The name of the file from which to read intergalactic medium state data.
* ``[fileName]`` — The name of the file from which to read intergalactic background light properties.
* ``[fileName]`` — The name of a file from which to read tabulated spectra of accretion disks.
* ``[fileName]`` — The name of the file from which to read a tabulated transfer function.

.. _physics-metaTreeProcessingTimeNull:

``metaTreeProcessingTimeNull``
------------------------------

A merger tree processing time class provides no estimates.

**(Default implementation)**

**Parameters**

* ``[dimensionless]`` (default ``.true.``) — If true the null profile is considered to be dimensionless.

.. _physics-metaTreeProcessingTimeTotalEvolveTime:

``metaTreeProcessingTimeTotalEvolveTime``
-----------------------------------------

A merger tree processing time estimator that estimates the remaining computation time based on the total time spent evolving nodes in the tree, using a power-law scaling with cosmic time. The time scaling exponent is set by ``[exponentTime]`` and the minimum interval between progress updates by ``[updateInterval]``.

**Parameters**

* ``[exponentTime]`` (default ``0.5d0``) — The exponent of cosmic time used in estimating the work associated with evolving a node.
* ``[updateInterval]`` (default ``10.0d0``) — The minimum interval (in seconds) between updates of the estimated time remaining.