.. _physics-haloModelPowerSpectrumModifier:

Halo Model Power Spectrum Modifier
==================================

Class providing modifiers to the one-halo and two-halo power spectrum terms in halo model galaxy clustering calculations. The ``modify`` method accepts the raw halo-model power spectrum at each wavenumber and modifies it in place for a specified term (one-halo or two-halo), allowing corrections such as baryonic feedback suppression, assembly bias, or scale-dependent effects to be applied without altering the underlying halo occupation distribution. Implementations may be mass-dependent (for per-halo corrections) or act globally on the full power spectrum array.

**Default implementation:** ``haloModelPowerSpectrumModifierIdentity``

Methods
-------

``modify`` → ``void``
   Modify the power spectra in the halo model of clustering.

   * ``double precision , intent(in ), dimension(: ) :: wavenumber``

   * ``type (enumerationHaloModelTermType), intent(in ) :: term``

   * ``double precision , intent(inout), dimension(: ) :: powerSpectrum``

   * ``double precision , intent(inout), dimension(:,:), optional :: powerSpectrumCovariance``

   * ``double precision , intent(in ) , optional :: mass``

.. _physics-haloModelPowerSpectrumModifierIdentity:

``haloModelPowerSpectrumModifierIdentity``
------------------------------------------

A halo model power spectrum modifier class which applies an identity modifier.

**(Default implementation)**

**Parameters**

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

.. _physics-haloModelPowerSpectrumModifierTriaxiality:

``haloModelPowerSpectrumModifierTriaxiality``
---------------------------------------------

A halo model power spectrum modifier class which attempts to modify power spectra to approximately account for the effects of halo triaxiality using the results of :cite:t:`smith_triaxial_2005`. Specifically, the one- and two-halo power spectra are multiplied by a correction factor, :math:`\Delta^2_\mathrm{triax}/\Delta^2_\mathrm{sphere}`, derived from the lower panels of Figures 3 and 2 of :cite:t:`smith_triaxial_2005` respectively for their "JS02" profile model. Given the uncertainty in this correction, the power spectrum covariance (if provided) is incremented by :math:`\epsilon^2 ( [\Delta^2_\mathrm{triax}/\Delta^2_\mathrm{sphere}-1] \otimes [\Delta^2_\mathrm{triax}/\Delta^2_\mathrm{sphere}-1)` where :math:`\epsilon=0.4` is chosen to approximate the difference between "continuity" and "JS02" profiles in :cite:t:`smith_triaxial_2005`.