[FLASH-USERS] Guardcells filling with PARAMESH4 data/grid structure

[Mark L Richardson]

Hi Marco,

Yes. This is exactly what is done in the mapping of particle data before a
gravity call.

Check out Grid_mapParticleToMesh.F90
in /source/Grid/GridParticles/GridParticlesMapToMesh/Paramesh/MoveSieve/

Cheers,
  -Mark

On Tue, Feb 21, 2012 at 2:55 PM, Marco Mazzuoli <marco.mazzuoli at unige.it>wrote:

>
>      Dear  Anshu, Dear Mark,
>
> thank you very much. You have answered exactly what I need.
> Actually, I supposed that information on the guard cell would have been
> lost when the pointer had beed relesed.
> Is it possible in such a way to make the changes on the guard cells
> effective in the interior cells of neighbouring blocks?
>
> Thank you again.
>
> Greetings,
>     Marco
>
>
>
> Ing. Marco Mazzuoli
> Dipartimento di Ingegneria
> delle Costruzioni, dell'Ambiente e
> del Territorio (DICAT)
> via Montallegro 1
> 16145 GENOVA-ITALY
> tel.  +39 010 353 2497
> cell. +39 338 7142904
> e-mail marco.mazzuoli at unige.it
>        marco.mazzuoli84 at gmail.com
>
>
>
>
>
>
> ------------------------------
> From: mlricha4 at asu.edu
> Date: Tue, 21 Feb 2012 09:21:59 -0700
> Subject: Re: [FLASH-USERS] Guardcells filling with PARAMESH4 data/grid
> structure
> To: dubey at flash.uchicago.edu
> CC: marco.mazzuoli at unige.it; flash-users at flash.uchicago.edu
>
> Just an add on to Anshu's email. The fillGuardCells call only fills the
> guard cells of active blocks (children and their parents). It's extremely
> unlikely you would need to fill beyond the active region, but in case you
> do, I have a routine that does this.
>
>    -Mark
>
> Sent from my iPhone
>
> On 2012-02-21, at 5:09 AM, Anshu Dubey <dubey at flash.uchicago.edu> wrote:
>
> Dear Marco,
>
> Grid_fillGuardCells is a global operation which replaces the current
> values in the guard cells of
> all blocks with values from interior cells of the neighboring blocks. When
> you get a pointer to a block
> you get access to all the variables in the block. In general, you should
> only be changing the
> interior cells in the block because the next call to guard cell fill will
> destroy the values you
> might have put in the guard cells. Any time you get a block through
> Grid_getBlkPtr, you
> should explicitly release it using Grid_releaseBlkPtr when you are done
> with it.
>
> The one exception to the above scenario is in the use of active particles
> where mass of the
> particles is mapped to their surrounding cells and some of those cells may
> be guard cells.
> A part of the routine Grid_mapParticlesToMesh makes sure that the values
> in guard cells
> are communicated back to appropriate blocks, in what we call the reverse
> guard cell fill.
>
> I hope that answers your basic question, please send me more details if
> you have a specific
> problem/approach in mind.
>
> Anshu
>
> On Fri, Feb 17, 2012 at 11:12 AM, Marco Mazzuoli <marco.mazzuoli at unige.it>wrote:
>
>
>     Dear all,
>
> I am working on the FLASH code implementing the PARAMESH4 data/grid
> structure.
> Could you clarify me some questions concerning the GuardCells (GC) filling?
>
> I explain the problem:
> In order to work on such a local block (with for example 4 GC) I get the
> pointer to that block with the subroutine "Grid_getBlkPtr".
> Then I could assign a new value to some GC variables.
> Finally I call the subroutine "Grid_fillGuardCells".
>
> My questions are:
> I)  What happens to GC values I had changed?
> II) Can I only read GC variables (like boundary conditions) or also write
> permanently a new value?
>
> In other words:
> i)   Which variable I'm really pointing with "Grid_getBlkPtr"?
> ii)  What I change indeed when I work on the GC of that pointer?
> iii) Do GC communicate straightforwardly to the adjacent block?
>
> Thank you to everybody.
>
> Sincerely,
>     Marco Mazzuoli
>
>
>
>
> Ing. Marco Mazzuoli
> Dipartimento di Ingegneria
>
> delle Costruzioni, dell'Ambiente e
> del Territorio (DICAT)
>
> via Montallegro 1
> 16145 GENOVA-ITALY
>
> tel.  +39 010 353 2497
>
>
> cell. +39 338 7142904
> e-mail marco.mazzuoli at unige.it
>
>        marco.mazzuoli84 at gmail.com
>
>
>
>
>
>
>
>
> --
>
> **********************************************************************************************************
> Anshu Dubey
> Associate Director and CS/Applications Group Leader          5747 S. Ellis
> Avenue 3rd Flr.
> Flash Center for Computational Science                                773
> 834 2999 (office)
> Fellow, Computation
> Institute                                                  312 420 0033(mobile)
> University of Chicago and Argonne National Laboratory        773 834 3230(fax)
>
> **********************************************************************************************************
>
>


-- 
Mark Richardson,
Mark.L.Richardson at asu.edu
Ph.D. Candidate: Astrophysics
PSF 271
School of Earth and Space Exploration
Arizona State University
480 318-4449
www.public.asu.edu/~mlricha4
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