Merge branch 'develop' into centre_for_cylinder_spherical_meshes

docs/source/io_formats/settings.rst

@@ -504,7 +504,10 @@ attributes/sub-elements:
       independent distributions of r-, cos_theta-, and phi-coordinates where
       cos_theta is the cosine of the angle with respect to the z-axis, phi is
       the azimuthal angle, and the sphere is centered on the coordinate
-      (x0,y0,z0).
+      (x0,y0,z0). A "mesh" spatial distribution samples source sites from a mesh element
+      based on the relative strengths provided in the node. Source locations
+      within an element are sampled isotropically. If no strengths are provided,
+      the space within the mesh is uniformly sampled.
 
       *Default*: None
 

docs/source/pythonapi/stats.rst

@@ -57,6 +57,7 @@ Spatial Distributions
    openmc.stats.SphericalIndependent
    openmc.stats.Box
    openmc.stats.Point
+   openmc.stats.MeshSpatial
 
 .. autosummary::
    :toctree: generated

docs/source/usersguide/settings.rst

@@ -187,7 +187,9 @@ The spatial distribution can be set equal to a sub-class of
 :class:`openmc.stats.CartesianIndependent`. To independently specify
 distributions using spherical or cylindrical coordinates, you can use
 :class:`openmc.stats.SphericalIndependent` or
-:class:`openmc.stats.CylindricalIndependent`, respectively.
+:class:`openmc.stats.CylindricalIndependent`, respectively. Meshes can also be
+used to represent spatial distributions with :class:`openmc.stats.MeshSpatial`
+by specifying a mesh and source strengths for each mesh element.
 
 The angular distribution can be set equal to a sub-class of
 :class:`openmc.stats.UnitSphere` such as :class:`openmc.stats.Isotropic`,