Add a reference to some literature.

git-svn-id: https://svn.dealii.org/trunk@24048 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/include/deal.II/lac/constraint_matrix.h b/deal.II/include/deal.II/lac/constraint_matrix.h
index 9442fbc223cd7fe6465de2180b4a75e69e9b2b1b..94f5364fe2cbf678b7b7144cf5990a8aeb263c52 100644 (file)
--- a/deal.II/include/deal.II/lac/constraint_matrix.h
+++ b/deal.II/include/deal.II/lac/constraint_matrix.h
@@ -107,6 +107,15 @@ namespace internals
  * been added, you need to call close(), which compresses the storage format
  * and sorts the entries.
  *
+ * @note Many of the algorithms this class implements are discussed in
+ * the @ref hp_paper . The algorithms are also related to those shown
+ * in <i>M. S. Shephard: Linear multipoint constraints applied via
+ * transformation as part of a direct stiffness assembly process. Int. J.
+ * Numer. Meth. Engrg., vol. 20 (1984), pp. 2107-2112.</i>, with the
+ * difference that the algorithms shown there completely eliminated
+ * constrained degrees of freedom, whereas we usually keep them as part
+ * of the linear system.
+ *
  * @ingroup dofs
  * @ingroup constraints
  * @author Wolfgang Bangerth, Martin Kronbichler, 1998, 2004, 2008, 2009