Fix preconditioner update wrapper and usage.

Used for the Dune::SeqILU preconditioner.
Using std::reference_wrapper by calling std::cref at the
call site ensures that the matrix is stored with reference
semantics, instead of copying the matrix from the initial call.

Author: Atgeirr Flø Rasmussen

opm/simulators/linalg/PreconditionerWithUpdate.hpp

@@ -22,6 +22,8 @@
 
 #include <dune/istl/preconditioner.hh>
 #include <memory>
+#include <tuple>
+#include <utility>
 
 namespace Dune
 {
@@ -109,7 +111,7 @@ template <class OriginalPreconditioner, class... Args>
 struct PreconditionerMaker : public GeneralPreconditionerMaker<OriginalPreconditioner> {
     using GenericPreconditioner = Preconditioner<typename OriginalPreconditioner::domain_type, typename OriginalPreconditioner::range_type>;
 
-    explicit PreconditionerMaker(Args&&... args)
+    explicit PreconditionerMaker(Args... args)
         : args_(args...)
     {
     }
@@ -136,7 +138,7 @@ class RebuildOnUpdatePreconditioner : public PreconditionerWithUpdate<typename O
 public:
     template<class... Args>
     explicit RebuildOnUpdatePreconditioner(Args... args)
-        : preconditioner_maker_(std::make_unique<PreconditionerMaker<OriginalPreconditioner, Args...>>(std::forward<Args>(args)...))
+        : preconditioner_maker_(std::make_unique<PreconditionerMaker<OriginalPreconditioner, Args...>>(args...))
     {
         update();
     }
@@ -192,8 +194,7 @@ template <class OriginalPreconditioner, class... Args>
 auto
 getRebuildOnUpdateWrapper(Args... args)
 {
-    return std::make_shared<RebuildOnUpdatePreconditioner<OriginalPreconditioner>>(
-        std::forward<Args>(args)...);
+    return std::make_shared<RebuildOnUpdatePreconditioner<OriginalPreconditioner>>(args...);
 }
 
 } // namespace Dune

opm/simulators/linalg/StandardPreconditioners_mpi.hpp

@@ -29,6 +29,9 @@
 #endif
 #endif
 
+#include <functional>
+#include <memory>
+#include <type_traits>
 
 namespace Opm {
 
@@ -154,7 +157,7 @@ struct StandardPreconditioners
             const double w = prm.get<double>("relaxation", 1.0);
             const bool resort = prm.get<bool>("resort", false);
             return wrapBlockPreconditioner<RebuildOnUpdatePreconditioner<Dune::SeqILU<M, V, V>>>(
-                comm, op.getmat(), n, w, resort);
+                comm, std::cref(op.getmat()), n, w, resort);
         });
         F::addCreator("dilu", [](const O& op, const P& prm, const std::function<V()>&, std::size_t, const C& comm) {
             DUNE_UNUSED_PARAMETER(prm);

opm/simulators/linalg/StandardPreconditioners_serial.hpp

@@ -29,6 +29,10 @@
 #endif
 #endif
 
+#include <functional>
+#include <memory>
+#include <type_traits>
+
 namespace Opm {
 
 template <class X, class Y>
@@ -66,7 +70,7 @@ struct StandardPreconditioners<Operator, Dune::Amg::SequentialInformation, typen
             const double w = prm.get<double>("relaxation", 1.0);
             const int n = prm.get<int>("ilulevel", 0);
             const bool resort = prm.get<bool>("resort", false);
-            return getRebuildOnUpdateWrapper<Dune::SeqILU<M, V, V>>(op.getmat(), n, w, resort);
+            return getRebuildOnUpdateWrapper<Dune::SeqILU<M, V, V>>(std::cref(op.getmat()), n, w, resort);
         });
         F::addCreator("paroverilu0", [](const O& op, const P& prm, const std::function<V()>&, std::size_t) {
             const double w = prm.get<double>("relaxation", 1.0);