Added 4d element types (#188)

* [feature][ElementTypes] Added 4d types pentatope (4d simplex) and tesseract (4d cube). (#95)

Co-authored-by: Jack S. Hale <[email protected]>
Co-authored-by: David A. Ham <[email protected]>
Co-authored-by: Matthew Scroggs <[email protected]>

* fix merge, add test

---------

Co-authored-by: dr-robertk <[email protected]>
Co-authored-by: Jack S. Hale <[email protected]>
Co-authored-by: David A. Ham <[email protected]>

test/test_cell.py

@@ -37,6 +37,20 @@ def test_hexahedron():
     assert cell.num_faces() == 6
 
 
+def test_pentatope():
+    cell = ufl.pentatope
+    assert cell.num_vertices() == 5
+    assert cell.num_edges() == 10
+    assert cell.num_faces() == 10
+
+
+def test_tesseract():
+    cell = ufl.tesseract
+    assert cell.num_vertices() == 16
+    assert cell.num_edges() == 32
+    assert cell.num_faces() == 24
+
+
 
 @pytest.mark.parametrize("cell", [ufl.interval])
 def test_cells_1d(cell):
@@ -53,12 +67,19 @@ def test_cells_2d(cell):
 
 
 @pytest.mark.parametrize("cell", [ufl.tetrahedron, ufl.hexahedron, ufl.prism, ufl.pyramid])
-def test_cells_2d(cell):
+def test_cells_3d(cell):
     assert cell.num_facets() == cell.num_faces()
     assert cell.num_ridges() == cell.num_edges()
     assert cell.num_peaks() == cell.num_vertices()
 
 
+@pytest.mark.parametrize("cell", [ufl.tesseract, ufl.pentatope])
+def test_cells_4d(cell):
+    assert cell.num_facets() == cell.num_sub_entities(3)
+    assert cell.num_ridges() == cell.num_faces()
+    assert cell.num_peaks() == cell.num_edges()
+
+
 def test_tensorproductcell():
     orig = ufl.TensorProductCell(ufl.interval, ufl.interval)
     cell = orig.reconstruct()

ufl/__init__.py

@@ -53,6 +53,8 @@
     - hexahedron
     - prism
     - pyramid
+    - pentatope
+    - tesseract
 
 * Domains::
 
@@ -339,7 +341,7 @@
 
 # Predefined convenience objects
 from ufl.objects import (
-    vertex, interval, triangle, tetrahedron,
+    vertex, interval, triangle, tetrahedron, pentatope, tesseract,
     quadrilateral, hexahedron, prism, pyramid, facet,
     i, j, k, l, p, q, r, s,
     dx, ds, dS, dP,
@@ -400,7 +402,7 @@
     'dc', 'dC', 'dO', 'dI', 'dX',
     'ds_b', 'ds_t', 'ds_tb', 'ds_v', 'dS_h', 'dS_v',
     'vertex', 'interval', 'triangle', 'tetrahedron',
-    'prism', 'pyramid',
+    'prism', 'pyramid', 'pentatope', 'tesseract',
     'quadrilateral', 'hexahedron', 'facet',
     'i', 'j', 'k', 'l', 'p', 'q', 'r', 's',
     'e', 'pi',

ufl/cell.py

@@ -196,6 +196,10 @@ def peak_types(self) -> typing.Tuple[AbstractCell, ...]:
               ("triangle", "quadrilateral", "quadrilateral", "quadrilateral", "triangle"), ("prism", )],
     "pyramid": [tuple("vertex" for i in range(5)), tuple("interval" for i in range(8)),
                 ("quadrilateral", "triangle", "triangle", "triangle", "triangle"), ("pyramid", )],
+    "pentatope": [tuple("vertex" for i in range(5)), tuple("interval" for i in range(10)),
+                  tuple("triangle" for i in range(10)), tuple("tetrahedron" for i in range(5)), ("pentatope", )],
+    "tesseract": [tuple("vertex" for i in range(16)), tuple("interval" for i in range(32)),
+                  tuple("quadrilateral" for i in range(24)), tuple("hexahedron" for i in range(8)), ("tesseract", )],
 }
 
 
@@ -422,6 +426,8 @@ def simplex(topological_dimension: int, geometric_dimension: typing.Optional[int
         return Cell("triangle", geometric_dimension)
     if topological_dimension == 3:
         return Cell("tetrahedron", geometric_dimension)
+    if topological_dimension == 4:
+        return Cell("pentatope", geometric_dimension)
     raise ValueError(f"Unsupported topological dimension for simplex: {topological_dimension}")
 
 
@@ -435,6 +441,8 @@ def hypercube(topological_dimension, geometric_dimension=None):
         return Cell("quadrilateral", geometric_dimension)
     if topological_dimension == 3:
         return Cell("hexahedron", geometric_dimension)
+    if topological_dimension == 4:
+        return Cell("tesseract", geometric_dimension)
     raise ValueError(f"Unsupported topological dimension for hypercube: {topological_dimension}")
 
 

ufl/finiteelement/elementlist.py

@@ -12,6 +12,7 @@
 # Modified by Marie E. Rognes <[email protected]>, 2010
 # Modified by Lizao Li <[email protected]>, 2015, 2016
 # Modified by Massimiliano Leoni, 2016
+# Modified by Robert Kloefkorn, 2022
 
 import warnings
 from numpy import asarray
@@ -82,12 +83,12 @@ def show_elements():
 #       the future, add mapping name as another element property.
 
 # Cell groups
-simplices = ("interval", "triangle", "tetrahedron")
-cubes = ("interval", "quadrilateral", "hexahedron")
+simplices = ("interval", "triangle", "tetrahedron", "pentatope")
+cubes = ("interval", "quadrilateral", "hexahedron", "tesseract")
 any_cell = (None,
             "vertex", "interval",
             "triangle", "tetrahedron", "prism",
-            "pyramid", "quadrilateral", "hexahedron")
+            "pyramid", "quadrilateral", "hexahedron", "pentatope", "tesseract")
 
 # Elements in the periodic table # TODO: Register these as aliases of
 # periodic table element description instead of the other way around

ufl/objects.py

@@ -37,6 +37,8 @@
 pyramid = Cell("pyramid", 3)
 quadrilateral = Cell("quadrilateral", 2)
 hexahedron = Cell("hexahedron", 3)
+tesseract = Cell("tesseract", 4)
+pentatope = Cell("pentatope", 4)
 
 # Facet is just a dummy declaration for RestrictedElement
 facet = "facet"