Merge branch 'deprecated-obsolete-ilu-implementations' into 'master'

Deprecated the classes SeqILU0 and SeqILUn

See merge request !175

CHANGELOG.md

 # Master (will become release 2.7)
 
+- Deprecated the preconditioner implementations `SeqILU0` and `SeqILUn`.
+  Use `SeqILU` instead, which implements incomplete LU decomposition
+  of any order.
+
 # Release 2.6
 
 - `BDMatrix` objects can now be constructed and assigned from `std::initializer_list`.

dune/istl/preconditioners.hh

@@ -647,9 +647,11 @@ namespace Dune {
      \tparam Y Type of the defect
      \tparam l Ignored. Just there to have the same number of template arguments
      as other preconditioners.
+
+     \deprecated Use SeqILU instead!
    */
   template<class M, class X, class Y, int l=1>
-  class SeqILU0 : public Preconditioner<X,Y> {
+  class DUNE_DEPRECATED_MSG("Use SeqILU instead of SeqILU0!") SeqILU0: public Preconditioner<X,Y> {
   public:
     //! \brief The matrix type the preconditioner is for.
     typedef typename std::remove_const<M>::type matrix_type;
@@ -734,9 +736,11 @@ namespace Dune {
      \tparam Y Type of the defect
      \tparam l Ignored. Just there to have the same number of template arguments
      as other preconditioners.
+
+     \deprecated Use SeqILU instead!
    */
   template<class M, class X, class Y, int l=1>
-  class SeqILUn : public Preconditioner<X,Y> {
+  class DUNE_DEPRECATED_MSG("Use SeqILU instead of SeqILUn!") SeqILUn : public Preconditioner<X,Y> {
   public:
     //! \brief The matrix type the preconditioner is for.
     typedef typename std::remove_const<M>::type matrix_type;