[MITgcm-support] identifying connected regions

[Jean-Michel Campin]

Hi Dan,

I think you could collect the full (global) 2-D field on 1 proc and work with
this. But you should be able also to design the algorithm that works on each tile
and then, with a couple of EXCH calls, finish the work at the global level.
But this second solution probably requires more careful coding.

On the side (I don't think it's that relevant here), in term of global
communication, I added (~ 10.y ago) a function to do a cummulative sum (cumulsum_z_tile.F).
in case there is some similarity with your problem.

Cheers,
Jean-Michel

On Wed, Feb 09, 2022 at 09:11:11AM +0000, Daniel Goldberg wrote:
> thanks very much martin. this should be possible to use directly.
> 
> best
> dan
> 
> On Wed, Feb 9, 2022 at 8:01 AM Martin Losch <Martin.Losch at awi.de> wrote:
> >
> > Hi Dan,
> >
> > I am not aware of any implementation of that within the MITgcm.
> >
> > There are gather and scatter routines in eesupp/src, e.g. gather_2d_r8.F
> >
> > Martin
> >
> > > On 7. Feb 2022, at 14:25, Daniel Goldberg <dan.goldberg at ed.ac.uk> wrote:
> > >
> > > Hello -
> > >
> > > I am curious if any part of model/src or a package implements an
> > > algorithm to identify connected regions of a 2D (or 3D) array?
> > >
> > > If not, i feel this might be best solved in serial, and am wondering
> > > if there are utilities to gather processor tiles to a single 2D array
> > > (and broadcast such an array to tiles) that should be used or are
> > > ideal to use. I am aware that something like this must be done with
> > > useSingleCpuIO but am not sure if this is the best template to follow.
> > >
> > > Many thanks
> > > Dan
> > >
> > > --
> > > Daniel Goldberg, PhD (he/him)
> > > Reader in Glaciology
> > > School of Geosciences, University of Edinburgh
> > > Geography Building, Drummond Street, Edinburgh EH8 9XP
> > >
> > >
> > > em: dan.goldberg at ed.ac.uk
> > > web: https://www.geos.ed.ac.uk/homes/dgoldber
> > > The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. Is e buidheann carthannais a th??? ann an Oilthigh Dhùn Èideann, clàraichte an Alba, àireamh clàraidh SC005336.
> > > _______________________________________________
> > > MITgcm-support mailing list
> > > MITgcm-support at mitgcm.org
> > > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> >
> > _______________________________________________
> > MITgcm-support mailing list
> > MITgcm-support at mitgcm.org
> > http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support