Update demo_tnt-elements.py

Author: jmv2009

python/demo/demo_tnt-elements.py

@@ -221,14 +221,15 @@ def create_tnt_quad(degree):
         pts, wts = basix.make_quadrature(basix.CellType.quadrilateral, 2 * degree)
         u = pts[:, 0]
         v = pts[:, 1]
-        pol0 = basix.polynomials.tabulate_polynomial_set(
+        pol_set = basix.polynomials.tabulate_polynomial_set(
             basix.CellType.quadrilateral, basix.PolynomialType.legendre, degree-2, 2, pts
         )
         # this assumes the conventional [0 to 1][0 to 1] domain of the reference element, 
         # and takes the Laplacian of (1-u)*u*(1-v)*v*poly, 
         # cf https://github.com/mscroggs/symfem/blob/main/symfem/elements/tnt.py
-        poly = (pol0[5]+pol0[3])*(u-1)*u*(v-1)*v+ \
-                2*(pol0[2]*(u-1)*u*(2*v-1)+pol0[1]*(v-1)*v*(2*u-1)+pol0[0]*((u-1)*u+(v-1)*v))
+        poly = (pol_set[5]+pol_set[3])*(u-1)*u*(v-1)*v+ \
+                2*(pol_set[2]*(u-1)*u*(2*v-1)+pol_set[1]*(v-1)*v*(2*u-1)+ \
+                   pol_set[0]*((u-1)*u+(v-1)*v))
         face_ndofs = poly.shape[0]
         x[2].append(pts)
         mat = np.zeros((face_ndofs, 1, len(pts), 1))