Relations

[Richard Guenther]

I'm a little bit confused about the ideas behind RelationListItem:

  virtual void notifyPreRead()
    {
      if (Pooma::isRelationGroupActive(groups_m) && dirty_m)
        {
          apply();
          clearDirty();
        }
    }

  virtual void notifyPostWrite()
    {
      setDirty();
    }

  virtual void setDirty()
    {
      dirty_m = true;
    }

  virtual void clearDirty()
    {
      dirty_m = false;
    }

why are _all_ these virtual?  The only ever overloaded is setDirty (from
InfluenceRelation).  Why do we have notifyPreRead()/notifyPostWrite() at
all?  We use setDirty() in Field.h and applyRelations (which uses
notifyPreRead - ok).

I guess my idea would be to make setDirty/clearDirty non-virtual and
explicitly use notifyPreRead()/notifyPostWrite() where previously
setDirty/applyRelations was used.

The reason I'm looking at all this is because writing to a Field which
is the target of an Influence relation gets this relation dirtied and
re-applied before reading (Ok, maybe it's not nice what I'm doing, but
at the first look, it's quite confusing).  So for me it would work
to override notifyPostWrite() in Relation1-n to do nothing.

So would be a patch like the one below ok?  There would be the opportunity
to remove Field::setDirty() and Field::clearDirty().  I would leave
Field::applyRelations() alone, but maybe do not call notifyPreRead() from
it but some sort of run() directly.

Richard.

--
Richard Guenther <richard dot guenther at uni-tuebingen dot de>
WWW: http://www.tat.physik.uni-tuebingen.de/~rguenth/


===== Field.h 1.15 vs edited =====
--- 1.15/r2/src/Field/Field.h	Thu May 27 10:56:35 2004
+++ edited/Field.h	Tue Jun 15 14:56:08 2004
@@ -1606,6 +1606,22 @@
     }
   }

+  /// notify relations of upcoming read
+  void notifyPreRead() const
+  {
+    for (int m = 0; m < numMaterials(); ++m)
+      for (int c = 0; c < centering().size(); ++c)
+        fieldEngine_m.data(m, c).relations().notifyPreRead();
+  }
+
+  /// notify relations of past write
+  void notifyPostWrite() const
+  {
+    for (int m = 0; m < numMaterials(); ++m)
+      for (int c = 0; c < centering().size(); ++c)
+        fieldEngine_m.data(m, c).relations().notifyPostWrite();
+  }
+
   /// dirty field, dirtying all relations
   void setDirty() const
   {
@@ -1630,6 +1646,20 @@
     }
   }

+  /// checks, if any of the fields relations is dirty
+  bool isDirty() const
+  {
+    for (int m = 0; m < numMaterials(); ++m)
+    {
+      for (int c = 0; c < centering().size(); ++ c)
+      {
+        if (fieldEngine_m.data(m, c).relations().dirty())
+	  return true;
+      }
+    }
+    return false;
+  }
+
   //@}

 private:
@@ -1853,7 +1883,7 @@
 // that it is going to be read and, therefore, needs to update itself.
 //
 // The second handles fields other than those with expression-engines by simply
-// calling applyRelations(). The third passes the tag to the leaves.
+// calling notifyPreRead(). The third passes the tag to the leaves.
 //
 // Fields with engines that store internal fields AND don't copy those
 // fields' relations to its list must provide a specialization to get the
@@ -1874,7 +1904,7 @@
   inline static
   Type_t apply(const Subject_t &f, const PerformUpdateTag &)
     {
-      f.applyRelations();
+      f.notifyPreRead();
       return 0;
     }
 };
@@ -2014,7 +2044,7 @@
           const Field<Mesh, T, EngineTag> &l = lhs.subField(m, c);

           if (AssignOpReadWriteTraits<Op>::readLHS)
-            l.applyRelations();
+            l.notifyPreRead();

           // Evaluate.

@@ -2023,7 +2053,7 @@
           // Having done the evaluation, we need to notify the LHS
           // that we've just written.

-          l.setDirty();
+          l.notifyPostWrite();
         }
     }

@@ -2053,7 +2083,7 @@
           forEach(r, PerformUpdateTag(), NullCombine());

           if (AssignOpReadWriteTraits<Op>::readLHS)
-            l.applyRelations();
+            l.notifyPreRead();

           // Evaluate.

@@ -2062,7 +2092,7 @@
           // Having done the evaluation, we need to notify the LHS
           // that we've just written.

-          l.setDirty();
+          l.notifyPostWrite();
         }
     }

@@ -2086,7 +2116,7 @@
           const Field<Mesh, T, EngineTag> &l = lhs.subField(m, c);

           if (AssignOpReadWriteTraits<Op>::readLHS)
-            l.applyRelations();
+            l.notifyPreRead();

           // Make an array out of the scalar.

@@ -2101,7 +2131,7 @@
           // Having done the evaluation, we need to notify the LHS
           // that we've just written.

-          l.setDirty();
+          l.notifyPostWrite();
         }
     }

===== Relations/RelationList.h 1.3 vs edited =====
--- 1.3/r2/src/Field/Relations/RelationList.h	Wed Dec  3 12:30:42 2003
+++ edited/Relations/RelationList.h	Tue Jun 15 15:03:23 2004
@@ -242,7 +242,10 @@


   //---------------------------------------------------------------------------
-  // Set/clear the dirty flags for all of the relations.
+  //@name dirty flag handling, deprecated
+  //@{
+
+  /// Set the dirty flags for all relations.

   void setDirty() const
     {
@@ -250,12 +253,25 @@
         list_m->elem(i)->setDirty();
     }

+  /// Set the dirty flags for all relations.
+
   void clearDirty() const
     {
       for (int i = 0; i < list_m->size(); ++i)
         list_m->elem(i)->clearDirty();
     }

+  /// Query if any of the relations is dirty.
+
+  bool dirty() const
+    {
+      for (int i = 0; i < list_m->size(); ++i)
+        if (list_m->elem(i)->dirty())
+	  return true;
+      return false;
+    }
+
+  //@}

   //---------------------------------------------------------------------------
   // Give access to a specific relation.
===== Evaluator/MultiArgEvaluator.h 1.19 vs edited =====
--- 1.19/r2/src/Evaluator/MultiArgEvaluator.h	Thu May 27 10:56:35 2004
+++ edited/Evaluator/MultiArgEvaluator.h	Tue Jun 15 14:50:38 2004
@@ -104,7 +104,7 @@
   template<class A>
   inline void dirtyRelations(const A &a, const WrappedInt<true>&) const
   {
-    a.setDirty();
+    a.notifyPostWrite();
   }

   template<class A>