Give the SphericalShell class a permanent manifold object.

include/aspect/geometry_model/spherical_shell.h

@@ -147,6 +147,16 @@ namespace aspect
          */
         SphericalShell() = default;
 
+        /**
+         * Initialization function. This function is called once at the
+         * beginning of the program after parse_parameters is run and after
+         * the SimulatorAccess (if applicable) is initialized.
+         * This function calls the initialize function of the manifold
+         * with a pointer to the initial topography model obtained
+         * from SimulatorAccess.
+         */
+        void initialize () override;
+
         /**
          * Generate a coarse mesh for the geometry described by this class.
          */
@@ -375,6 +385,24 @@ namespace aspect
          * Flag whether the 2D quarter shell is periodic in phi.
          */
         bool periodic;
+
+        /**
+         * An object that describes the geometry. This pointer is
+         * initialized in the initialize() function, and serves as the manifold
+         * object that the triangulation is later given in create_coarse_mesh()
+         * where the triangulation clones it.
+         *
+         * The object is marked as 'const' to make it clear that it should not
+         * be modified once created. That is because the triangulation copies it,
+         * and modifying the current object will not have any impact on the
+         * manifold used by the triangulation.
+         */
+        std::unique_ptr<const internal::SphericalManifoldWithTopography<dim>> manifold;
+
+        /**
+         * Give a symbolic name to the manifold id to be used by this class.
+         */
+        static const types::manifold_id my_manifold_id = 99;
     };
   }
 }

source/geometry_model/spherical_shell.cc

@@ -138,6 +138,15 @@ namespace aspect
 
 
 
+    template <int dim>
+    void
+    SphericalShell<dim>::initialize ()
+    {
+      manifold = std::make_unique<internal::SphericalManifoldWithTopography<dim>>();
+    }
+
+
+
     template <int dim>
     void
     SphericalShell<dim>::
@@ -328,7 +337,7 @@ namespace aspect
 
       // Use a manifold description for all cells. Use manifold_id 99 in order
       // not to step on the boundary indicators used below.
-      coarse_grid.set_manifold (99, internal::SphericalManifoldWithTopography<dim>());
+      coarse_grid.set_manifold (my_manifold_id, *manifold);
       set_manifold_ids(coarse_grid);
     }
 
@@ -339,7 +348,7 @@ namespace aspect
     SphericalShell<dim>::set_manifold_ids (parallel::distributed::Triangulation<dim> &triangulation) const
     {
       for (const auto &cell : triangulation.active_cell_iterators())
-        cell->set_all_manifold_ids (99);
+        cell->set_all_manifold_ids (my_manifold_id);
     }