[MITgcm-support] exch2 with lat lon grid

[Jean-Michel Campin]

Hi Matt,

In your case (using pkg/exch2 with blank-tiles), the domain tile mapping
is set according to tile-size (from SIZE.h) and "dimsFacets=" from data.exch2;

So, if the total number of tiles ( nSx*nPx*nSy*nPy ) is not a prime number,
may be if you manage to split it between nSx*nPx and nSy*nPy 
you might be able to keep these 2 numbers < 1000 ?

Otherwise, we will need to change this "I3.3" to by-pass this limitation.

Cheers,
Jean-Michel

On Sat, Dec 27, 2014 at 10:43:40AM -0800, Matthew Mazloff wrote:
> Hello
> 
> EXCH2 package works great!
> 
> Bringing me to my next question:
> 
> Is there a trick for using more than 999 cores? I assume setting nPy>999 is an issue since the mdsio routines have statements with:
> 
>          WRITE(dataFName,'(2A,I3.3,A,I3.3,A)')
>      &              pfName(1:pIL),'.',iG,'.',jG,'.data'
> 
> Is there an easy fix (e.g. to ini_procs.F) for this issue?
> 
> Thanks!
> Matt
> 
> 
> 
> On Dec 21, 2014, at 1:00 PM, Matthew Mazloff <mmazloff at ucsd.edu> wrote:
> 
> > Hi Patrick
> > 
> > I saw that but it seemed too simple -- glad to hear that works! So to confirm, there is no need to set any fancy topology files, the trick is just to set
> > nPy =   Number of cores needed,
> > 
> > and then in data.exch2
> >  W2_mapIO   = 1,
> > so the code knows it was nPy that was set to "Number of cores needed"
> > and then:
> > dimsFacets = NX, NY,
> > so it can rebuild the grid.
> > 
> > and that is it?
> > 
> > I'll give it a try -- sounds great!
> > 
> > Thanks
> > Matt
> > 
> > 
> > 
> > 
> > 
> > 
> > On Dec 21, 2014, at 12:09 PM, Patrick Heimbach <heimbach at mit.edu> wrote:
> > 
> >> Hi Matt,
> >> 
> >> yes, a simple example is the parallel version of verification/global_ocean.90x40x15/
> >> i.e. take a look at
> >> code/SIZE.h_mpi
> >> input/data.exch2.mpi
> >> 
> >> p.
> >> 
> >> On Dec 21, 2014, at 2:54 PM, Matthew Mazloff <mmazloff at ucsd.edu> wrote:
> >> 
> >>> Hello
> >>> 
> >>> I have a lat-lon grid with a good number of blank tiles. Is it possible to use exch2 such that I can request fewer cores?  Is there an example of how to implement this for a simple grid? 
> >>> 
> >>> Thanks!
> >>> Matt
> >>> 
> >>> 
> >>> _______________________________________________
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> >>> MITgcm-support at mitgcm.org
> >>> http://mitgcm.org/mailman/listinfo/mitgcm-support
> >> 
> >> 
> >> ---
> >> Patrick Heimbach | heimbach at mit.edu | http://www.mit.edu/~heimbach
> >> MIT | EAPS 54-1420 | 77 Massachusetts Ave | Cambridge MA 02139 USA
> >> FON +1-617-253-5259 | FAX +1-617-253-4464 | SKYPE patrick.heimbach
> >> 
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> > 
> > 
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