init public members with nullptr for more meaningful fault messages if not set

dune/solvers/iterationsteps/projectedblockgsstep.cc

@@ -5,6 +5,8 @@ template<class MatrixType, class VectorType>
 inline
 void ProjectedBlockGSStep<MatrixType, VectorType>::iterate()
 {
+	assert(hasObstacle_!=nullptr);
+	
     if (hasObstacle_->size()!= (unsigned int)this->x_->size())
         DUNE_THROW(SolverError, "Size of hasObstacle (" << hasObstacle_->size()
                    << ") doesn't match solution vector (" << this->x_->size() << ")");
@@ -46,6 +48,8 @@ void ProjectedBlockGSStep<MatrixType, VectorType>::iterate()
 
             // Solve the local constraint minimization problem
             // We use a projected Gauss-Seidel, for lack of anything better
+            assert(obstacles_!=nullptr);
+            
             Obstacle defectObstacle = (*obstacles_)[i];
             defectObstacle -= x;