Re: [Freepooma-devel] [RFC] Change domain object default constructorbehavior

[Richard Guenther]

ron hylton wrote:
> Richard, I'm not quite sure what the real goal is (I've never looked at
> UninitializedVector) so this may not work or might be considered lying
> to the compiler, but perhaps it will at least generate some other ideas.
> 
> template <class X>
> struct XNoInit : public X
> {
>     XNoInit() : X(NoInit()) {}
> };
> 
> template <class Bar, int Dim>
> struct FooNoInit
> {
>     XNoInit<Bar> x[Dim];
> };
> 
> If the choice of initialization strategy needs to be controlled at
> compile time you could use a Loki-type Select to choose an appropriate
> type for x.

Indeed - it looks hackish, but it does work :)  With the simple attached
patch, performance of ScalarCode using code that uses Loc for indexing
improves by 13%!  I'll try to extend this to all domain objects.

Thanks for the suggestion,
Richard.

? DomainIterator.h.optimized
? LINUXgcc
? Loc.h.opt
? tests/LINUXgcc
? tests/loc.cpp
? tests/loc.cpp.t70.optimized
? tests/loc.s
Index: DomainTraits.Loc.h
===================================================================
RCS file: /cvsroot/freepooma/freepooma/src/Domain/DomainTraits.Loc.h,v
retrieving revision 1.34
diff -u -r1.34 DomainTraits.Loc.h
--- DomainTraits.Loc.h  1 Nov 2004 18:16:32 -0000       1.34
+++ DomainTraits.Loc.h  6 Apr 2005 18:10:41 -0000
@@ -81,7 +81,7 @@
  * The specialization of DomainTraits for Loc, for dimensions greater than
  * one.
  */
-
+struct Loc1NoInit;
 template<int Dim>
 struct DomainTraits< Loc<Dim> >
   : public DomainTraitsDomain<Loc<Dim>, int, Dim>
@@ -101,7 +101,8 @@
   typedef Loc<Dim>      MultResult_t;
 
   // type for storage of this domain's data
-  typedef UninitializedVector<OneDomain_t,Dim,Element_t> Storage_t;
+  //typedef UninitializedVector<OneDomain_t,Dim,Element_t> Storage_t;
+  typedef Loc1NoInit Storage_t[Dim];
 
   // necessary static data
   enum { domain = Base_t::domain };
@@ -135,7 +136,10 @@
   }
 
   // Domains get the chance to do special initialization.
-  static void initializeStorage(Storage_t &dom) { dom.initialize(); }
+  //static void initializeStorage(Storage_t &dom) { dom.initialize(); }
+  static void initializeStorage(Storage_t &dom) {
+    InitializeUninitializedVector<OneDomain_t, Dim-1>::initialize(&dom[0]);
+  }
 
 
   // addAccum means dom += newdom
Index: Loc.h
===================================================================
RCS file: /cvsroot/freepooma/freepooma/src/Domain/Loc.h,v
retrieving revision 1.34
diff -u -r1.34 Loc.h
--- Loc.h       10 Feb 2005 16:02:06 -0000      1.34
+++ Loc.h       6 Apr 2005 18:10:41 -0000
@@ -657,6 +657,10 @@
   o << "]";
 }
 
+struct Loc1NoInit : public Loc<1>
+{
+       Loc1NoInit() : Loc<1>(Pooma::NoInit()) {}
+};
 
 /// print a Loc to a stream, in the format
 ///   "[" first, first, ... first "]"