Update documentation

diff --git a/include/deal.II/fe/mapping_fe_field.h b/include/deal.II/fe/mapping_fe_field.h
index ef9398253105b33662c16168884a13235008c28c..7de5b744dcde0c7fceb017ffb94e1887c8144d15 100644 (file)
--- a/include/deal.II/fe/mapping_fe_field.h
+++ b/include/deal.II/fe/mapping_fe_field.h
@@ -122,23 +122,22 @@ public:
   /**
    * Constructor taking vectors on the multigrid levels rather than the active
    * cells only. The vector of vectors is expected to have as many entries as
-   * there are levels in the triangulation and provide valid data on each
-   * level, i.e., be of compatible length DoFHandler::n_dofs(level). Apart
-   * from the source of the vectors, the same arguments as in the other
-   * constructor need to be provided.
+   * there are global levels in the triangulation and provide valid data on
+   * each level, i.e., be of compatible length DoFHandler::n_dofs(level). A
+   * prerequisite of this constructor is that DoFHandler::distribute_mg_dofs()
+   * has been called. Apart from the level vectors, the same arguments as in
+   * the other constructor need to be provided.
    */
   MappingFEField(const DoFHandlerType &         euler_dof_handler,
                  const std::vector<VectorType> &euler_vector,
                  const ComponentMask &          mask = ComponentMask());
 
   /**
-   * Constructor taking vectors on the multigrid levels rather than the active
-   * cells only, variant with MGLevelObject instead of std::vector. The vector
-   * of vectors is expected to have as many entries as there are levels in the
-   * triangulation and provide valid data on each level, i.e., be of
-   * compatible length DoFHandler::n_dofs(level). Apart from the source of the
-   * vectors, the same arguments as in the other constructor need to be
-   * provided.
+   * Constructor with MGLevelObject instead of std::vector, otherwise the same
+   * as above. It is required that `euler_vector.max_level()+1` equals the
+   * global number of levels in the triangulation. The minimum level may be
+   * zero or more &mdash; it only needs to be consistent between what is set
+   * here and later used for evaluation of the mapping.
    */
   MappingFEField(const DoFHandlerType &           euler_dof_handler,
                  const MGLevelObject<VectorType> &euler_vector,

diff --git a/source/fe/mapping_fe_field.cc b/source/fe/mapping_fe_field.cc
index 5e0420a0c8fde337ca2834d2bdce25ec8ff21e97..04dd115174f99bf14355913666932b88386df018 100644 (file)
--- a/source/fe/mapping_fe_field.cc
+++ b/source/fe/mapping_fe_field.cc
@@ -290,9 +290,9 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::MappingFEField(
   AssertDimension(size, spacedim);
 
   Assert(euler_dof_handler.has_level_dofs(),
-         ExcMessage("The underlying did not call distribute_mg_dofs(). "
-                    "In this case, the construction via level vectors does not "
-                    "make sense."));
+         ExcMessage("The underlying DoFHandler object did not call "
+                    "distribute_mg_dofs(). In this case, the construction via "
+                    "level vectors does not make sense."));
   AssertDimension(euler_vector.size(),
                   euler_dof_handler.get_triangulation().n_global_levels());
   this->euler_vector.clear();
@@ -329,17 +329,17 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::MappingFEField(
   AssertDimension(size, spacedim);
 
   Assert(euler_dof_handler.has_level_dofs(),
-         ExcMessage("The underlying did not call distribute_mg_dofs(). "
-                    "In this case, the construction via level vectors does not "
-                    "make sense."));
-  AssertDimension(euler_vector.max_level() + 1 - euler_vector.min_level(),
+         ExcMessage("The underlying DoFHandler object did not call "
+                    "distribute_mg_dofs(). In this case, the construction via "
+                    "level vectors does not make sense."));
+  AssertDimension(euler_vector.max_level() + 1,
                   euler_dof_handler.get_triangulation().n_global_levels());
   this->euler_vector.clear();
   this->euler_vector.resize(
     euler_dof_handler.get_triangulation().n_global_levels());
   for (unsigned int i = euler_vector.min_level(); i <= euler_vector.max_level();
        ++i)
-    this->euler_vector[i - euler_vector.min_level()] = &euler_vector[i];
+    this->euler_vector[i] = &euler_vector[i];
 }
 
 
@@ -399,6 +399,14 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::get_vertices(
                   fe_values.n_quadrature_points);
   AssertDimension(fe_to_real.size(),
                   euler_dof_handler->get_fe().n_components());
+  if (uses_level_dofs)
+    {
+      AssertIndexRange(cell->level(), euler_vector.size());
+      AssertDimension(euler_vector[cell->level()]->size(),
+                      euler_dof_handler->n_dofs(cell->level()));
+    }
+  else
+    AssertDimension(euler_vector[0]->size(), euler_dof_handler->n_dofs());
 
   {
     std::lock_guard<std::mutex> lock(fe_values_mutex);
@@ -413,6 +421,7 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::get_vertices(
 
   const VectorType &vector =
     uses_level_dofs ? *euler_vector[cell->level()] : *euler_vector[0];
+
   std::array<Point<spacedim>, GeometryInfo<dim>::vertices_per_cell> vertices;
   for (unsigned int i = 0; i < dofs_per_cell; ++i)
     {
@@ -2447,6 +2456,14 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::update_internal_dofs(
 
   typename DoFHandlerType::cell_iterator dof_cell(*cell, euler_dof_handler);
   Assert(uses_level_dofs || dof_cell->active() == true, ExcInactiveCell());
+  if (uses_level_dofs)
+    {
+      AssertIndexRange(cell->level(), euler_vector.size());
+      AssertDimension(euler_vector[cell->level()]->size(),
+                      euler_dof_handler->n_dofs(cell->level()));
+    }
+  else
+    AssertDimension(euler_vector[0]->size(), euler_dof_handler->n_dofs());
 
   if (uses_level_dofs)
     dof_cell->get_mg_dof_indices(data.local_dof_indices);
@@ -2455,6 +2472,7 @@ MappingFEField<dim, spacedim, VectorType, DoFHandlerType>::update_internal_dofs(
 
   const VectorType &vector =
     uses_level_dofs ? *euler_vector[cell->level()] : *euler_vector[0];
+
   for (unsigned int i = 0; i < data.local_dof_values.size(); ++i)
     data.local_dof_values[i] =
       internal::ElementAccess<VectorType>::get(vector,