[amg] don't copy temporary data durint copy-construction

if on the initial AMG pre was called, it is currently it not necessary to
call pre on a copy of that AMG. This is a feature that is not required
by the Preconditioner interface and thus it nothing anybody can rely on.
We now don't copy the temporary data anymore.

dune/istl/paamg/amg.hh

@@ -304,15 +304,7 @@ namespace Dune
       coarseSmoother_(amg.coarseSmoother_),
       category_(amg.category_),
       verbosity_(amg.verbosity_)
-    {
-#warning why do we need this? The vectors are re-created in AMG::pre(x)
-      if(amg.rhs_)
-        rhs_ = std::make_shared<Hierarchy<Range,A>>(*amg.rhs_);
-      if(amg.lhs_)
-        lhs_ = std::make_shared<Hierarchy<Domain,A>>(*amg.lhs_);
-      if(amg.update_)
-        update_ = std::make_shared<Hierarchy<Domain,A>>(*amg.update_);
-    }
+    {}
 
     template<class M, class X, class S, class PI, class A>
     AMG<M,X,S,PI,A>::AMG(const OperatorHierarchy& matrices, CoarseSolver& coarseSolver,

dune/istl/paamg/test/pthreadamgtest.cc

@@ -96,15 +96,6 @@ void *solve(void* arg)
   pthread_exit(NULL);
 }
 
-void *solve1(void* arg)
-{
-  thread_arg *amgarg=(thread_arg*) arg;
-  *amgarg->x=0;
-  (*amgarg->amg).apply(*amgarg->x,*amgarg->b);
-  (*amgarg->amg).post(*amgarg->x);
-  return 0;
-}
-
 void *solve2(void* arg)
 {
   thread_arg *amgarg=(thread_arg*) arg;
@@ -199,21 +190,6 @@ void testAMG(int N, int coarsenTarget, int ml)
   }
   void* retval;
 
-  for(int i=0; i < NUM_THREADS; ++i)
-    pthread_join(threads[i], &retval);
-
-  amgs.clear();
-  args.clear();
-  amg.pre(x, b);
-  amgs.resize(NUM_THREADS, amg);
-  for(int i=0; i < NUM_THREADS; ++i)
-  {
-    args[i].amg=&amgs[i];
-    args[i].b=&bs[i];
-    args[i].x=&xs[i];
-    args[i].fop=&fop;
-    pthread_create(&threads[i], NULL, solve1, (void*) &args[i]);
-  }
   for(int i=0; i < NUM_THREADS; ++i)
     pthread_join(threads[i], &retval);
 

dune/istl/paamg/test/pthreadtwoleveltest.cc

@@ -77,15 +77,6 @@ void *solve(void* arg)
   pthread_exit(NULL);
 }
 
-void *solve1(void* arg)
-{
-  thread_arg *amgarg=(thread_arg*) arg;
-  *amgarg->x=0;
-  (*amgarg->amg).apply(*amgarg->x,*amgarg->b);
-  (*amgarg->amg).post(*amgarg->x);
-  return 0;
-}
-
 void *solve2(void* arg)
 {
   thread_arg *amgarg=(thread_arg*) arg;
@@ -173,21 +164,6 @@ void testTwoLevelMethod()
   }
   void* retval;
 
-  for(int i=0; i < NUM_THREADS; ++i)
-    pthread_join(threads[i], &retval);
-
-  amgs.clear();
-  args.clear();
-  preconditioner.pre(x, b);
-  amgs.resize(NUM_THREADS, preconditioner);
-  for(int i=0; i < NUM_THREADS; ++i)
-  {
-    args[i].amg=&amgs[i];
-    args[i].b=&bs[i];
-    args[i].x=&xs[i];
-    args[i].fop=&fop;
-    pthread_create(&threads[i], NULL, solve1, (void*) &args[i]);
-  }
   for(int i=0; i < NUM_THREADS; ++i)
     pthread_join(threads[i], &retval);