Initialise IterativeSolver::iterationStep_

dune/solvers/solvers/iterativesolver.hh

@@ -60,7 +60,7 @@ namespace Dune {
         void writeIterate(const VectorType& iterate, int iterationNumber) const;
 
         //! The iteration step used by the algorithm
-        IterationStep<VectorType, BitVectorType>* iterationStep_;
+        IterationStep<VectorType, BitVectorType>* iterationStep_ = nullptr;
 
         /** \brief The requested tolerance of the solver */
         double tolerance_;