[MITgcm-support] Objective Function for Ptracers

[Yohei Takano - BAS]

Hi all,

   I think I found a solution (moreover a mistake), some how my  AUTODIFF option
was turned off but after I turned this on,

useAUTODIFF  =  .TRUE.,

   the model starts to generate the objective function file (although beside this file generation
everything seems to be proceeding (i.e. the model did not crash) so it took me some time to figure out.

   Actually this is a good timing to also follow up and ask about AUTODIFF, so in data.autodiff,
I usually turn KPP/Redi off in adjoint mode (according to my colleague, for a numerical stability reason)

 “useKPPinAdMode =  .FALSE.,”
 “useGMRediInAdMode  =  .FALSE.,”

   ... but is this the general approach for adjoint simulations (like in ECCOv4 or other setups)?
I am wondering whether this has an impact on the results etc. Hope I can understand more on what is behind.

Sincerely,

Yohei












________________________________
From: Yohei Takano - BAS
Sent: 12 November 2024 10:21
To: mitgcm-support at mitgcm.org <mitgcm-support at mitgcm.org>
Subject: Objective Function for Ptracers

Dear all,

   I am trying to run adjoint simulations using  Ptracers as an objective function in ECCOv4 framework.
Pkg/ecco has capability using Ptracers as an objective function (setting data.ecco) and
I set gencost_barfile(1) = 'm_boxmean_ptracer', and gencost_itracer(1) = 1 to define
box mean ptracer (tracer #1) as an objective function.

   However, unlike temperature and salinity, the model does not generate adm_ file for Ptracers.
(Here is an error I obtained).

(PID.TID 0000.0001) *** ERROR ***  MDS_READ_FIELD: filename: adm_boxmean_ptracer.0000000012.data
(PID.TID 0000.0001) *** ERROR ***  MDS_READ_FIELD: File does not exist

   I thought "adm_boxmean_ptracer.0000000012.data" should be automatically generated so I was wondering
I forgot to turn some settings on (or off) (and I looked at the codes and 'm_boxmean_ptracer' option exists).
The setup is based on ECCOv4r2 + Ptracers and pkg/dic turned on. The MITgcm checkpoint is 67z.

   Does anyone know a reason why adm_ file is not generate for Ptracers (again it works for "m_boxmean_theta"
and ? (and costfunction0012 contains value for Ptracers). I will also attach the data.ecco below.
Thank you in advance.

Regards,

Yohei

----- data.ecco -----

# *******************
# ECCO Cost Functions
# *******************
 &ECCO_COST_NML
 &
# ***************************
# ECCO Generic Cost Functions
# ***************************
 &ECCO_GENCOST_NML
 gencost_name(1) = 'ptracer_ad',
 gencost_barfile(1) = 'm_boxmean_ptracer',
 gencost_avgperiod(1) = 'month',
 gencost_itracer(1) = 1,
 gencost_msk_is3d(1)=.TRUE.,
 gencost_outputlevel(1) = 1,
 gencost_mask(1) = 'mask',
 mult_gencost(1) = 1.0D9,
 &
#




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