Cheap fix for deprecated NewtonSolver - should switch to NonlinearProblem.

Author: jhale

demo/demo_nonlinear-naghdi-clamped-semicylinder.py

@@ -45,7 +45,7 @@
 from dolfinx.fem import Expression, Function, dirichletbc, functionspace, locate_dofs_topological
 from dolfinx.fem.bcs import DirichletBC
 from dolfinx.fem.function import Function as _Function
-from dolfinx.fem.petsc import NonlinearProblem, apply_lifting, assemble_vector, set_bc
+from dolfinx.fem.petsc import NewtonSolverNonlinearProblem, apply_lifting, assemble_vector, set_bc
 from dolfinx.mesh import CellType, create_rectangle, locate_entities_boundary
 from dolfinx.nls.petsc import NewtonSolver
 from ufl import grad, inner, split
@@ -545,8 +545,8 @@ def compute_cell_contributions(V, points):
     at that point"""
     # Determine what process owns a point and what cells it lies within
     mesh = V.mesh
-    point_ownership_data = dolfinx.cpp.geometry.determine_point_ownership(
-        mesh._cpp_object, points, 1e-6
+    point_ownership_data = dolfinx.geometry.determine_point_ownership(
+        mesh, points, 1e-6
     )
 
     owning_points = np.asarray(point_ownership_data.dest_points).reshape(-1, 3)
@@ -589,7 +589,7 @@ def compute_cell_contributions(V, points):
 # We define a custom `NonlinearProblem` which is able to include the point
 # force.
 # %%
-class NonlinearProblemPointSource(NonlinearProblem):
+class NonlinearProblemPointSource(NewtonSolverNonlinearProblem):
     def __init__(
         self,
         F: ufl.form.Form,