CGStep: hold preconditioner in a `shared_ptr`

dune/solvers/iterationsteps/cgstep.cc

@@ -4,6 +4,9 @@
 #include <dune/solvers/common/canignore.hh>
 #include <dune/matrix-vector/genericvectortools.hh>
 
+namespace Dune {
+namespace Solvers {
+
 template <class MatrixType, class VectorType, class Ignore>
 void CGStep<MatrixType, VectorType, Ignore>::check() const
 {
@@ -19,7 +22,7 @@ void CGStep<MatrixType, VectorType, Ignore>::preprocess()
 
     if (preconditioner_) {
         using CanIgnore_t = CanIgnore<Ignore>;
-        CanIgnore_t *asCanIgnore = dynamic_cast<CanIgnore_t*>(preconditioner_);
+        CanIgnore_t *asCanIgnore = dynamic_cast<CanIgnore_t*>(preconditioner_.get());
         if (asCanIgnore != nullptr and this->hasIgnore())
             asCanIgnore->setIgnore(this->ignore());
 
@@ -59,3 +62,6 @@ void CGStep<MatrixType, VectorType, Ignore>::iterate()
     p_ += q;
     r_squared_old_ = r_squared;
 }
+
+} /* namespace Solvers */
+} /* namespace Dune */