Add a couple comments.

git-svn-id: https://svn.dealii.org/trunk@20886 0785d39b-7218-0410-832d-ea1e28bc413d

diff --git a/deal.II/lac/include/lac/constraint_matrix.h b/deal.II/lac/include/lac/constraint_matrix.h
index 63d75bff6a7721522b67af3627a54c6b4c45a301..9e745bb0cb4b25ee85cca8e70f6854497c190203 100644 (file)
--- a/deal.II/lac/include/lac/constraint_matrix.h
+++ b/deal.II/lac/include/lac/constraint_matrix.h
@@ -1093,7 +1093,11 @@ class ConstraintMatrix : public Subscriptor
                                       * global object, one saves the call to
                                       * the condense function after the
                                       * vectors and matrices are fully
-                                      * assembled.
+                                      * assembled. On the other hand, by
+                                      * consequence, the function does not
+                                      * only write into the entries enumerated
+                                      * by the @p local_dof_indices array, but
+                                      * also (possibly) others as necessary.
                                      *
                                      * Note that this function will apply all
                                       * constraints as if they were
@@ -1149,7 +1153,15 @@ class ConstraintMatrix : public Subscriptor
                                       * global object, one saves the call to
                                       * the condense function after the
                                       * vectors and matrices are fully
-                                      * assembled.
+                                      * assembled. On the other hand, by
+                                      * consequence, the function does not
+                                      * only write into the entries enumerated
+                                      * by the @p local_dof_indices array, but
+                                      * also (possibly) others as
+                                      * necessary. This includes writing into
+                                      * diagonal elements of the matrix if the
+                                      * corresponding degree of freedom is
+                                      * constrained.
                                      *
                                      * The fourth argument
                                      * <tt>local_matrix</tt> is intended to