Respond to comments on #990. Add FE example notebook.

docs/source/examples/expansion-filters.rst

@@ -0,0 +1,13 @@
+.. _notebook_expansion:
+
+=====================
+Functional Expansions
+=====================
+
+.. only:: html
+
+    .. notebook:: ../../../examples/jupyter/expansion-filters.ipynb
+
+.. only:: latex
+
+    IPython notebooks must be viewed in the online HTML documentation.

docs/source/examples/index.rst

@@ -1,13 +1,12 @@
 .. _examples:
 
-=================
-Example Notebooks
-=================
+========
+Examples
+========
 
-The following series of Jupyter_ Notebooks provide examples for usage of OpenMC
-features via the :ref:`pythonapi`.
-
-.. _Jupyter: https://jupyter.org/
+The following series of `Jupyter <https://jupyter.org/>`_ Notebooks provide
+examples for how to use various features of OpenMC by leveraging the
+:ref:`pythonapi`.
 
 -----------
 Basic Usage
@@ -20,6 +19,7 @@ Basic Usage
     post-processing
     pandas-dataframes
     tally-arithmetic
+    expansion-filters
     search
     triso
     candu

openmc/filter_expansion.py

@@ -226,17 +226,22 @@ class SpatialLegendreFilter(ExpansionFilter):
 class SphericalHarmonicsFilter(ExpansionFilter):
     r"""Score spherical harmonic expansion moments up to specified order.
 
+    This filter allows you to obtain real spherical harmonic moments of either
+    the particle's direction or the cosine of the scattering angle. Specifying a
+    filter with order :math:`\ell` tallies moments for all orders from 0 to
+    :math:`\ell`.
+
     Parameters
     ----------
     order : int
-        Maximum spherical harmonics order
+        Maximum spherical harmonics order, :math:`\ell`
     filter_id : int or None
         Unique identifier for the filter
 
     Attributes
     ----------
     order : int
-        Maximum spherical harmonics order
+        Maximum spherical harmonics order, :math:`\ell`
     id : int
         Unique identifier for the filter
     cosine : {'scatter', 'particle'}

src/math.F90

@@ -181,7 +181,7 @@ contains
   end function calc_pn
 
 !===============================================================================
-! CALC_RN calculates the n-th order spherical harmonics for a given angle
+! CALC_RN calculates the n-th order real spherical harmonics for a given angle
 ! (in terms of (u,v,w)).  All Rn,m values are provided (where -n<=m<=n)
 !===============================================================================
 

src/tallies/tally_filter_sph_harm.F90

@@ -24,7 +24,8 @@ module tally_filter_sph_harm
   integer, parameter :: COSINE_PARTICLE = 2
 
 !===============================================================================
-! LEGENDREFILTER gives Legendre moments of the change in scattering angle
+! SPHERICALHARMONICSFILTER gives spherical harmonics expansion moments of a
+! tally score
 !===============================================================================
 
   type, public, extends(TallyFilter) :: SphericalHarmonicsFilter
@@ -149,7 +150,7 @@ contains
         order = f % order
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a spherical harmonics filter.")
       end select
     end if
   end function openmc_sphharm_filter_get_order
@@ -183,7 +184,7 @@ contains
 
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a spherical harmonics filter.")
       end select
     end if
   end function openmc_sphharm_filter_get_cosine
@@ -203,7 +204,7 @@ contains
         f % n_bins = (order + 1)**2
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to set order on a non-expansion filter.")
+        call set_errmsg("Not a spherical harmonics filter.")
       end select
     end if
   end function openmc_sphharm_filter_set_order
@@ -233,7 +234,7 @@ contains
 
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a spherical harmonics filter.")
       end select
     end if
   end function openmc_sphharm_filter_set_cosine

src/tallies/tally_filter_sptl_legendre.F90

@@ -25,7 +25,8 @@ module tally_filter_sptl_legendre
   integer, parameter :: AXIS_Z = 3
 
 !===============================================================================
-! SpatialLEGENDREFILTER gives Legendre moments
+! SPATIALLEGENDREFILTER gives Legendre moments of the particle's normalized
+! position along an axis
 !===============================================================================
 
   type, public, extends(TallyFilter) :: SpatialLegendreFilter
@@ -97,18 +98,20 @@ contains
   subroutine to_statepoint(this, filter_group)
     class(SpatialLegendreFilter), intent(in) :: this
     integer(HID_T),      intent(in) :: filter_group
+    character(kind=C_CHAR) :: axis
 
     call write_dataset(filter_group, "type", "spatiallegendre")
     call write_dataset(filter_group, "n_bins", this % n_bins)
     call write_dataset(filter_group, "order", this % order)
     select case (this % axis)
     case (AXIS_X)
-      call write_dataset(filter_group, 'axis', 'x')
+      axis = 'x'
     case (AXIS_Y)
-      call write_dataset(filter_group, 'axis', 'y')
+      axis = 'y'
     case (AXIS_Z)
-      call write_dataset(filter_group, 'axis', 'z')
+      axis = 'z'
     end select
+    call write_dataset(filter_group, 'axis', axis)
     call write_dataset(filter_group, 'min', this % min)
     call write_dataset(filter_group, 'max', this % max)
   end subroutine to_statepoint
@@ -118,7 +121,18 @@ contains
     integer,             intent(in) :: bin
     character(MAX_LINE_LEN)         :: label
 
-    label = "Legendre expansion, P" // trim(to_str(bin - 1))
+    character(1) :: axis
+
+    select case (this % axis)
+    case (AXIS_X)
+      axis = 'x'
+    case (AXIS_Y)
+      axis = 'y'
+    case (AXIS_Z)
+      axis = 'z'
+    end select
+    label = "Legendre expansion, " // axis // " axis, P" // &
+         trim(to_str(bin - 1))
   end function text_label
 
 !===============================================================================
@@ -138,7 +152,7 @@ contains
         order = f % order
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a spatial Legendre filter.")
       end select
     end if
   end function openmc_spatial_legendre_filter_get_order
@@ -158,7 +172,7 @@ contains
         f % n_bins = order + 1
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to set order on a non-expansion filter.")
+        call set_errmsg("Not a spatial Legendre filter.")
       end select
     end if
   end function openmc_spatial_legendre_filter_set_order
@@ -182,7 +196,7 @@ contains
         max = f % max
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to set order on a non-expansion filter.")
+        call set_errmsg("Not a spatial Legendre filter.")
       end select
     end if
   end function openmc_spatial_legendre_filter_get_params
@@ -206,7 +220,7 @@ contains
         if (present(max)) f % max = max
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to set order on a non-expansion filter.")
+        call set_errmsg("Not a spatial Legendre filter.")
       end select
     end if
   end function openmc_spatial_legendre_filter_set_params

src/tallies/tally_filter_zernike.F90

@@ -129,7 +129,7 @@ contains
         order = f % order
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a Zernike filter.")
       end select
     end if
   end function openmc_zernike_filter_get_order
@@ -152,7 +152,7 @@ contains
         r = f % r
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a Zernike filter.")
       end select
     end if
   end function openmc_zernike_filter_get_params
@@ -172,7 +172,7 @@ contains
         f % n_bins = ((order + 1)*(order + 2))/2
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to set order on a non-expansion filter.")
+        call set_errmsg("Not a Zernike filter.")
       end select
     end if
   end function openmc_zernike_filter_set_order
@@ -195,7 +195,7 @@ contains
         if (present(r)) f % r = r
       class default
         err = E_INVALID_TYPE
-        call set_errmsg("Tried to get order on a non-expansion filter.")
+        call set_errmsg("Not a Zernike filter.")
       end select
     end if
   end function openmc_zernike_filter_set_params