Fix typos in comments

dune/istl/multitypeblockmatrix.hh

@@ -164,7 +164,7 @@ namespace Dune {
 
   public:
     /**
-     * do y -= A x in next row
+     * do y += A x in next row
      */
     static void umv(TVecY& y, const TMatrix& A, const TVecX& x) {
       static const int rowlen = mpl::size< typename mpl::at_c<TMatrix,crow>::type >::value;

dune/istl/tutorial/example.cc

@@ -584,7 +584,7 @@ void test_MultiTypeBlockVector_MultiTypeBlockMatrix() {
   Dune::MatrixAdapter<CM_BCRS,TestVector,TestVector> op(A);             // make linear operator from A
   Dune::SeqJac<CM_BCRS,TestVector,TestVector,2> jac(A,1,1);                // Jacobi preconditioner
   Dune::SeqGS<CM_BCRS,TestVector,TestVector,2> gs(A,1,1);                  // GS preconditioner
-  Dune::SeqSOR<CM_BCRS,TestVector,TestVector,2> sor(A,1,1.9520932);        // SSOR preconditioner
+  Dune::SeqSOR<CM_BCRS,TestVector,TestVector,2> sor(A,1,1.9520932);        // SOR preconditioner
   Dune::SeqSSOR<CM_BCRS,TestVector,TestVector,2> ssor(A,1,1.0);      // SSOR preconditioner
 
   Dune::LoopSolver<TestVector> loop(op,gs,1E-4,18000,2);           // an inverse operator