}
+//TODO[WB]: We should have a function of the kind
+// ConstraintMatrix::add_constraint (const unsigned int constrained_dof,
+// const std::vector<std::pair<unsigned int, double> > &entries,
+// const double inhomogeneity = 0);
+// rather than building up constraints piecemeal through add_line/add_entry
+// etc. This would also eliminate the possibility of accidentally changing
+// existing constraints into something pointless, see the discussion on the
+// mailing list on "Tiny bug in interpolate_boundary_values" in Sept. 2010.
+
/**
* This class implements dealing with linear (possibly inhomogeneous)
* constraints on degrees of freedom. In particular, it handles constraints of
* boundary conditions (the standard way that is extensively discussed in the
* tutorial programs is to use MatrixTools::apply_boundary_values). The
* general principle of Dirichlet conditions are algebraic constraints of the
- * form $x_{i} = b_i$, which fits into the form described above.
+ * form $x_{i} = b_i$, which fits into the form described above.
*
* Please note that when combining adaptively refined meshes with hanging node
* constraints and inhomogeneous Dirichlet boundary conditions within one