Automate docs element list for interpolation

docs/source/element_list.py

@@ -1,5 +1,8 @@
 from finat.ufl.elementlist import ufl_elements
-from finat.element_factory import supported_elements
+from finat.element_factory import supported_elements, create_element
+from finat.ufl import FiniteElement
+from ufl.cell import TensorProductCell
+from ufl import interval, quadrilateral
 import csv
 
 shape_names = {
@@ -8,28 +11,42 @@
     2: 'tensor'
     }
 
-def cells(cellnames):
+firedrake_cells = ("interval",
+                   "triangle",
+                   "tetrahedron",
+                   "quadrilateral",
+                   "hexahedron")
 
-    firedrake_cells = ("interval",
-                       "triangle",
-                       "tetrahedron",
-                       "quadrilateral",
-                       "hexahedron")
 
-    cells = [c for c in cellnames if c in firedrake_cells]
-
-    return(", ".join(cells))
+def cells(cell_list):
+    return(", ".join(cell_list))
 
 
 with open("element_list.csv", 'w', newline='') as csvfile:
     csvwriter = csv.writer(csvfile)
 
     for element in supported_elements:
         family, short_name, value_rank, sobolev_space, \
-            mapping, degree_range, cellnames = ufl_elements[element]
+            mapping, degree_range, cell_list = ufl_elements[element]
 
+        cell_list = [c for c in cell_list if c in firedrake_cells]
         short_name = short_name if short_name != family else ""
-        cellnames = cells(cellnames)
+        cellnames = cells(cell_list)
         shape = shape_names[value_rank]
 
-        csvwriter.writerow((family, short_name, shape, cellnames))
+        if family in {"NCE", "NCF"}:
+            cell = TensorProductCell(quadrilateral, interval)
+        else:
+            cell = cell_list[0]
+
+        ufl_elem = FiniteElement(family, cell=cell, degree=degree_range[0])
+        finat_element = create_element(ufl_elem)
+
+        try:
+            finat_element.dual_basis
+        except NotImplementedError:
+            interpolatable = "No"
+        else:
+            interpolatable = "Yes"
+
+        csvwriter.writerow((family, short_name, shape, cellnames, interpolatable))

docs/source/interpolation.rst

@@ -267,12 +267,6 @@ function space has any finite element which supports interpolation, as specified
 spaces can also be interpolated into from other meshes as long as they are
 constructed from these spaces.
 
-.. note::
-
-   The list of supported elements above is only for *target* function spaces.
-   Function spaces on the *source* mesh can be built from most of the supported
-   elements.
-
 There are few constraints on the meshes involved: the target mesh can have a
 different cell shape, topological dimension, or resolution to the source mesh.
 There are many use cases for this: For example, two solutions to the same

docs/source/variational-problems.rst

@@ -267,11 +267,13 @@ extrusion <extruded-meshes>` for details.
 Supported finite elements
 -------------------------
 
-Firedrake supports the use of the following finite elements.
+Firedrake supports the use of the following finite elements. The last column
+specifies if we support interpolation **into** a function space built from the element.
+Interpolation **from** a function space is universally supported.
 
 .. csv-table::
-    :header: "Name", "Short name", "Value shape", "Valid cells"
-    :widths: 20, 10, 10, 40
+    :header: "Name", "Short name", "Value shape", "Valid cells", "Valid interpolation target?"
+    :widths: 20, 10, 10, 40, 10
     :file: element_list.csv
 
 In addition, the

pyproject.toml

@@ -19,7 +19,8 @@ dependencies = [
   "mpi4py>3; python_version >= '3.13'",
   "mpi4py; python_version < '3.13'",
   "fenics-ufl>=2025.3",
-  "firedrake-fiat>=2026.4",
+  # TODO RELEASE
+  "firedrake-fiat @ git+https://github.com/firedrakeproject/fiat.git@release",
   "h5py>3.12.1",
   "immutabledict",
   "libsupermesh",