[MeL] Document MeshSubset ctors and a little more.

MeshLib/MeshSubset.h

@@ -28,19 +28,37 @@ namespace MeshLib
 class MeshSubset
 {
 public:
-    /// construct from nodes
+    /// Construct a mesh subset from vector of nodes on the given mesh.
+    /// \param msh Mesh
+    /// \param vec_items Vector of Node pointers.
+    /// \param delete_ptr Deletes the vector of Node pointers if true.
+    /// \note When delete_ptr is set only the vector is deleted, not the
+    /// elements of the vector.
     MeshSubset(const Mesh& msh, std::vector<Node*> const* vec_items,
         bool const delete_ptr = false)
         : _msh(msh), _nodes(vec_items), _eles(nullptr), _delete_ptr(delete_ptr)
     {}
 
-    /// construct from elements
+    /// Construct a mesh subset from vector of elements on the given mesh.
+    /// \param msh Mesh
+    /// \param vec_items Vector of Element pointers.
+    /// \param delete_ptr Deletes the vector of Element pointers if true.
+    /// \note When delete_ptr is set only the vector is deleted, not the
+    /// elements of the vector.
     MeshSubset(const Mesh& msh, std::vector<Element*> const* vec_items,
         bool const delete_ptr = false)
         : _msh(msh), _nodes(nullptr), _eles(vec_items), _delete_ptr(delete_ptr)
     {}
 
     /// construct from both nodes and elements
+    /// Construct a mesh subset from vector of nodes and a vector of elements on
+    /// the given mesh.
+    /// \param msh Mesh
+    /// \param vec_nodes Vector of Node pointers.
+    /// \param vec_eles Vector of Element pointers.
+    /// \param delete_ptr Deletes the vector of Node pointers if true.
+    /// \note When delete_ptr is set only the vectors are deleted, not the
+    /// elements of the vectors.
     MeshSubset(const Mesh& msh, std::vector<Node*> const* vec_nodes,
         std::vector<Element*> const* vec_eles, bool const delete_ptr = false)
         : _msh(msh), _nodes(vec_nodes), _eles(vec_eles), _delete_ptr(delete_ptr)
@@ -127,6 +145,8 @@ public:
             active_nodes->push_back(n);
         }
 
+        // Transfer the ownership of active_nodes to the new MeshSubset, which
+        // deletes the pointer itself.
         return new MeshSubset(_msh, active_nodes, true);
     }