[MOAB-dev] Edges at the ends of a periodic mesh?

[Timothy J. Tautges]

----- Original Message -----
> From: "Robert Jacob" <jacob at mcs.anl.gov>
> To: "Timothy J. Tautges" <tautges at mcs.anl.gov>
> Cc: "Iulian Grindeanu" <iulian at mcs.anl.gov>, moab-dev at mcs.anl.gov
> Sent: Wednesday, May 23, 2012 11:17:06 PM
> Subject: Re: [MOAB-dev] Edges at the ends of a periodic mesh?
> This was motivated by a more practical question. If there are N cells
> in the j-direction, there will be N+1 edges but the last is the same
> as
> the first. So in the call to box create, do we specify N vertices in
> the j-direction or N+1? I'm still not sure.
> 

In parallel, N+1, with is_periodic false.  In serial, N, with is_periodic true.

- tim

> Rob
> 
> 
> On 5/23/12 10:26 PM, Timothy J. Tautges wrote:
> > Yes. But, in parallel, each piece of mesh looks like a serial mesh,
> > so locally it won't appear periodic (the right hand edge will be
> > distinct from the left hand edge). Logically across processors,
> > though, the right edge on the rightmost processor will be the same
> > as the left edge on the leftmost processor. If you write the mesh to
> > a single file, there will be a common edge between the rightmost and
> > leftmost quad.
> >
> > - tim
> >
> > ----- Original Message -----
> > From: "Robert Jacob"<jacob at mcs.anl.gov>
> > To: "Timothy J. Tautges"<tautges at mcs.anl.gov>
> > Cc: "Iulian Grindeanu"<iulian at mcs.anl.gov>, moab-dev at mcs.anl.gov
> > Sent: Wednesday, May 23, 2012 9:13:20 PM
> > Subject: Re: [MOAB-dev] Edges at the ends of a periodic mesh?
> >
> >
> >
> > On 5/23/12 9:01 PM, Timothy J. Tautges wrote:
> >> Be careful about the parallel case though, where on each proc
> >> sharing the edge the edge is represented.
> >
> > So in the parallel case the edge WOULD be represented on both sides
> > if
> > there are multiple processors in the j direction?
> >
> > Rob
> >
> >>
> >> Also, if you're just trying to create all the edges in one big
> >> batch, just put all the quads in a range, then call
> >> get_adjacencies, with the last argument Interface::UNION, and that
> >> should create/return all of them.
> >>
> >> - tim
> >>
> >> ----- Original Message -----
> >> From: "Iulian Grindeanu"<iulian at mcs.anl.gov>
> >> To: "Robert Jacob"<jacob at mcs.anl.gov>
> >> Cc: moab-dev at mcs.anl.gov
> >> Sent: Wednesday, May 23, 2012 12:34:12 PM
> >> Subject: Re: [MOAB-dev] Edges at the ends of a periodic mesh?
> >>
> >>
> >>
> >>
> >> ----- Original Message -----
> >>
> >>
> >>
> >> Hi,
> >>
> >> If I have a 2D rectangular mesh which is periodic in one direction,
> >> lets
> >> say the j direction, then the leftmost and rightmost edge of the
> >> mesh
> >> are really the same edge. Do they both need to be declared in MOAB?
> >> Or
> >> does the periodic property mean you only need to describe one of
> >> the
> >> edges and the other end will know its adjacent to it?
> >>
> >> Thanks,
> >> Rob
> >> Hi,
> >> I assume that you use ScdInterface;
> >> If the box is periodic in j direction, the nodes in that direction
> >> will be "periodic".
> >> Nodes are not duplicated, the edges that you get on the leftmost
> >> and rightmost sides are really pointing to the same nodes, they
> >> will not be duplicated, either.
> >>
> >> How do you get edges after you create quads?
> >> You can use "get_adjacency" methods, with "create_if_missing" flag
> >> true. Only one edge would be created.
> >> The problem is that the order in which these are created is not
> >> very "structured"
> >> Or do you create them with new scd boxes, of dimension 1, in a loop
> >> over i (and then j?)? In that case, you have complete control over
> >> "order" they are created in.
> >> I hope this helps.
> >> Iulian
> >>
> >>
> >> Iulian
> >>
> >