.. _phase-tabphase_irregular:

Tabulated phase function (irregular angular grid) (:monosp:`tabphase_irregular`)
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.. pluginparameters::

 * - values
   - |string|
   - A comma-separated list of phase function values parameterized by the
     cosine of the scattering angle. Must have the same length as `nodes`.
   - |exposed|

 * - nodes
   - |string|
   - A comma-separated list of :math:`\cos \theta` specifying the grid on which
     `values` are defined. Bounds must be [-1, 1] and values must be strictly
     increasing. Must have the same length as `values`.
   - |exposed|

This plugin implements a generic phase function model for isotropic media
parametrized by a lookup table giving values of the phase function as a
function of the cosine of the scattering angle.

This plugin is a variant of the ``tabphase`` plugin and behaves similarly but
uses an irregular distribution internally. Consequently, ``tabphase`` performs
better for evaluation and sampling.