[Freepooma-devel] another stupid thought

[Roman Krylov]

Hi again.
Does Array<N,Vector<n,T> > have regular memory alignment for it's data 
so that if I have a pointer to the first elment(of T type), I can 
calculate pointer to 2nd and so on?
It's all about autovect :)
   they say It supports strided access.
And maybe it'll be advantageous sometimes to make some operations like 
+= or *= without PETE?
These operations can not avoid temporaries with PETE, do I understand it 
right?
So if I have N '+=' I have N {tmp = LHS + RHS; LHS=tmp} so if RHS is 
some complex expression which can benefit from PETE,
if it won't be bunched with LHS, there'll be no big loss, but I can 
benefit from vectorizing first statement in {...}.

Thanks.
Roman.

P.S. Maybe it'll be good to add new mailing list for crazy ideas ? :) 
not to clutter freepooma-devel

> Hi.
> Thanks for multiple patches!
> honestly I haven't tested it yet, I'm still using my hacked version of 
> InterpolatorCIC.h
> I'll check them somehow this week.
> Performance enhancements mentioned earlier are attractive of course :)
>
> And what about autovectorization: haven't you tried Devang Patel's 
> '#pragma ivdep' patch in autovect-branch?
> When I tried it - some rejections emerged and no other information 
> since then. But I even don't know what to anticipate from it - would 
> it be able to vectorize operations on arrays of Vector<,>s? and, is 
> the problem only in aliasing or there are some other obstacles? and 
> would it be worth for operations with explicit L-R dependence like '+='?
>
> By the way, about shortcoming I've encountered earlier: as you had 
> mentioned, without indexes' boundaries checking the cellContaining() 
> works, but SEGFAULTs. In addition: if position attributes are out of 
> domain, but position[i]-origin (Vector<,> type) has all positive 
> numbers,  then there's no SEGFAULT, but strange behaviour occures and 
> segfaults if one of position[i]-origin coordinate is <0.
> So there should be always some BC having coincident boundaries with 
> mesh(as in PIC2d). And sync() or smth other invoking BCs should be 
> before gather or scatter.
>
> Thanks.
> Roman.
>
> > On Mon, 11 Apr 2005, Richard Guenther wrote:
> >
> >  
> >
> > > On Mon, 11 Apr 2005, Richard Guenther wrote:
> > >
> > >   
> > >
> > > > On Fri, 1 Apr 2005, Richard Guenther wrote:
> > > >
> > > >     
> > > >
> > > > > Hi!
> > > > >
> > > > > This patch canonicalizes the handling of hasInternalGuards_m and
> > > > > hasExternalGuards_m in the various grid layouts.  It also disables
> > > > > optimizing away of internal guards if the partitioner will create
> > > > > at most one patch.
> > > > >       
> > > >
> > > > I believe that the current way of doing things is correct (apart
> > > > from not all places being consistent), i.e. have hasInternalGuards
> > > > and guards() being consistent.  What the Interpolators really
> > > > are asking from the Layouts is the maximum supported stencil size,
> > > > a thing the layouts cannot answer atm.  For this we need to provide
> > > > functionality.
> > > >     
> >
> > Like the attached patch.  Roman - does this work for you?
> >
> > Richard.
> >
> >
> > 2005Apr11  Richard Guenther <address@hidden>
> >
> >     * src/Particles/Interpolation.h (getMaximumStencilWidth):
> >     New function.
> >     src/Particles/InterpolatorCIC.h: Use it, instead of relying
> >     on internal guards.
> >     src/Particles/InterpolatorSUDS.h: Likewise.
> >  
> >
> > ------------------------------------------------------------------------
> >
> > ? LINUXgcc
> > ? LINUXgcc-opt
> > ? tests/LINUXgcc
> > ? tests/LINUXgcc-opt
> > Index: Interpolation.h
> > ===================================================================
> > RCS file: /cvsroot/freepooma/freepooma/src/Particles/Interpolation.h,v
> > retrieving revision 1.10
> > diff -u -r1.10 Interpolation.h
> > --- Interpolation.h    1 Nov 2004 18:16:59 -0000    1.10
> > +++ Interpolation.h    11 Apr 2005 12:56:24 -0000
> > @@ -220,6 +220,25 @@
> > void setExternalGuards(const Field&, typename Field::Element_t);
> >
> >
> > +/// getMaximumStencilWidth returns the maximum extent a stencil may
> > +/// have if operating on the physical domain.
> > +
> > +template <class Layout>
> > +GuardLayers<Layout::dimensions> getMaximumStencilWidth(const Layout& l)
> > +{
> > +  GuardLayers<Layout::dimensions> gl = l.externalGuards();
> > +  if (l.sizeGlobal() > 1) {
> > +    for (int i=0; i<Layout::dimensions; ++i) {
> > +      if (l.internalGuards().lower(i) < gl.lower(i))
> > +    gl.lower(i) = l.internalGuards().lower(i);
> > +      if (l.internalGuards().upper(i) < gl.upper(i))
> > +    gl.upper(i) = l.internalGuards().upper(i);
> > +    }
> > +  }
> > +  return gl;
> > +}
> > +
> > +
> > #include "Particles/Interpolation.cpp"
> >
> >
> > Index: InterpolatorCIC.h
> > ===================================================================
> > RCS file: /cvsroot/freepooma/freepooma/src/Particles/InterpolatorCIC.h,v
> > retrieving revision 1.12
> > diff -u -r1.12 InterpolatorCIC.h
> > --- InterpolatorCIC.h    1 Nov 2004 18:16:59 -0000    1.12
> > +++ InterpolatorCIC.h    11 Apr 2005 12:56:24 -0000
> > @@ -152,7 +152,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate guard layers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -188,7 +188,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate guard layers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -231,7 +231,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -281,7 +281,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -320,7 +320,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -365,7 +365,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -412,7 +412,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -449,7 +449,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -492,7 +492,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for CIC
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > Index: InterpolatorSUDS.h
> > ===================================================================
> > RCS file: 
> > /cvsroot/freepooma/freepooma/src/Particles/InterpolatorSUDS.h,v
> > retrieving revision 1.12
> > diff -u -r1.12 InterpolatorSUDS.h
> > --- InterpolatorSUDS.h    1 Nov 2004 18:16:59 -0000    1.12
> > +++ InterpolatorSUDS.h    11 Apr 2005 12:56:24 -0000
> > @@ -153,7 +153,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate guard layers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -189,7 +189,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate guard layers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -232,7 +232,7 @@
> >         "Field and Particle Position must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -282,7 +282,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -321,7 +321,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -366,7 +366,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -413,7 +413,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -450,7 +450,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> > @@ -493,7 +493,7 @@
> >         "Field and Particle CacheData must have same number of 
> > patches!");
> >
> >       // Check that the Field has adequate GuardLayers for SUDS
> > -      const GuardLayers<Dim>& gl = field.layout().internalGuards();
> > +      GuardLayers<Dim> gl = getMaximumStencilWidth(field.layout());
> >       for (int d=0; d<Dim; ++d)
> >         {
> >           PInsist(gl.lower(d)>=1 && gl.upper(d)>=1,
> >  
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Freepooma-devel mailing list
> > address@hidden
> > http://lists.nongnu.org/mailman/listinfo/freepooma-devel
> >  
>
>
>
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