[MITgcm-devel] do we need exch_z ?

[Chris Hill]

Detective JM,

 Another weirdness. 
 In adjustment.cs I do the following

 1 - base run (OL=2, no exch_z in ini_curvi )
 2 - base + OL=3
 3 - base + OL=3 + viscA4
 4 - base + OL=3 + viscA4 + exch_z in ini_curvi

 I for init_res in output I get

 1 == 2
 3 == 4
 2 != 3

 Does that make sense?

Chris

> -----Original Message-----
> From: mitgcm-devel-bounces at mitgcm.org 
> [mailto:mitgcm-devel-bounces at mitgcm.org] On Behalf Of Chris Hill
> Sent: Tuesday, February 24, 2004 9:11 PM
> To: MITgcm-devel at mitgcm.org
> Subject: RE: [MITgcm-devel] do we need exch_z ?
> 
> JM,
> 
>  I have started looking into this. However, I have run into a 
> weird prob on one processor for which I need your ace 
> detective skills. If I set OL=3 for either aim_5l.cs or 
> global_ocean.cs and use exch_z the run crashes. Do you see 
> anything like this (on one proc)? I'm using ifc.
> 
> Chris 
> 
> > -----Original Message-----
> > From: mitgcm-devel-bounces at mitgcm.org 
> > [mailto:mitgcm-devel-bounces at mitgcm.org] On Behalf Of Jean-Michel 
> > Campin
> > Sent: Tuesday, February 24, 2004 7:39 PM
> > To: MITgcm-devel at mitgcm.org
> > Subject: [MITgcm-devel] do we need exch_z ?
> > 
> > Hi,
> > 
> > Here is what I found, trying to run cs-32x32 on 6 cpu:
> > 
> > a) presently, there is no exch_Z in pkg/exch2 but 
> > ini_curvilinear_grid.F call 3 times exch_Z (for xG, yG, and
> > rAz) The consequence is that the exch1 version of exch_Z
> > (eesupp/src) is used instead, which is fine on 1 processor but make 
> > the model blowing up after 2 iterations when trying on 6 cpu.
> > 
> > b) if I comment out the 3 calls to exch_Z, aim.5l_cs produces 
> > identical results on 1 and 6 cpu.
> > 
> > But the problem is that rAz, xG, yG (and fCoriG) and no 
> longer valid 
> > outside (1:sNx+1,1:sNy+1). This is likely to cause problems with 
> > high-order momentum advection (VI form) and high-order viscosity. 
> > (Alistair, can you confirm ?).
> > 
> > c) I had a quick look at
> > MITgcm_contrib/high_res_cube/code-mods/ini_curvilinear_grid.F
> > and did not see any call to exch_Z.
> > Is it possible that rAz is set to zero outside of 
> (1:sNx+1,1:sNy+1) ?
> > and has some effect on the blowing up at the edgde of the cube ?
> > 
> > Jean-Michel
> > _______________________________________________
> > MITgcm-devel mailing list
> > MITgcm-devel at mitgcm.org
> > http://dev.mitgcm.org/mailman/listinfo/mitgcm-devel
> > 
> 
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