[MITgcm-support] STOP MOM_IMPLICIT_R: error when solving 3-Diag problem.

Jody Klymak jklymak at uvic.ca
Sun Sep 13 11:22:54 EDT 2020


Hi Kunal.

Check STDOUT.0000 as that is more relevant.  Does the cfl criteria blow up?  If so, you will simply have to reduce the time step. Its possible you have also set the model up incorrectly and it is convecting initially, which will easily violate the cfl criteria.  It is also hard to tell fro what you are giving us when the model blows up.  time step 1?  time step 100? Finally, its often useful to plot the fields to see where the instability is happening.  That may require you to save quite a bit of data, but its hard to debug in the absence of information. 

Best of luck!  Jody

> On 13 Sep 2020, at 07:22, kunal madkaiker <kunal.madkaiker02 at gmail.com> wrote:
> 
> Hi Gus,
> 
> As per your suggestion, I made the respective changes and tried to run the executable again. Below is the log generated
> 
> $ mpirun -np 60 ./mitgcmuv 
> forrtl: error (72): floating overflow
> Image              PC                                    Routine                     Line          Source             
> libifcoremt.so.5   00002AD443246555         for__signal_handl     Unknown     Unknown
> libpthread-2.17.s  00002AD442DB35F0       Unknown               Unknown       Unknown
> libnetcdf.so.15.2  00002AD44121C4B3       __libm_exp_e7         Unknown     Unknown
> mitgcmuv           0000000000AC0FF7        exf_bulkformulae_        4598         exf_bulkformulae.f
> mitgcmuv           0000000000B02334         exf_getforcing_          4430           exf_getforcing.f
> mitgcmuv           000000000128726E         load_fields_drive        2141           load_fields_driver.f
> mitgcmuv           0000000000C45A25        forward_step_            2340           forward_step.f
> mitgcmuv           0000000001290200         main_do_loop_            2078         main_do_loop.f
> mitgcmuv           0000000001C283F6         the_main_loop_           2097        the_main_loop.f
> mitgcmuv           0000000001C28955         the_model_main_          2421      the_model_main.f
> mitgcmuv           0000000001290615         MAIN__                   4286            main.f
> mitgcmuv           0000000000403412         Unknown                Unknown      Unknown
> libc-2.17.so <http://libc-2.17.so/>       00002AD445C2A505        __libc_start_main    Unknown      Unknown
> mitgcmuv           0000000000403319         Unknown                Unknown      Unknown
> ----------------------------------------------------------------------------------------------------------------------------------------------
> 
> The STDERR file reads:
> (PID.TID 0030.0001) ** WARNING ** MNC_READPARMS: incomplete MNC pickup files implementation
> (PID.TID 0030.0001) ** WARNING ** MNC_READPARMS: => pickup_write_mnc=T not recommanded
> (PID.TID 0030.0001) ** WARNING ** MNC_READPARMS: => pickup_read_mnc=T not working for some set-up
> (PID.TID 0030.0001) ** WARNING ** INI_MODEL_IO: globalFiles=TRUE is not safe in Multi-processors (MPI) run
> (PID.TID 0030.0001) ** WARNING ** INI_MODEL_IO: use instead "useSingleCpuIO=.TRUE."
> (PID.TID 0030.0001) ** WARNING ** INI_MODEL_IO: use tiled-files to write sections (for OBCS)
> (PID.TID 0030.0001) ** WARNING ** EXF_CHECK: wind-stress position irrelevant
> 
> Attaching data, data.obcs, data.exf for your reference. I have set deltaTmom=120.0,
> What I am understanding is that the model is blowing up due to overestimation of few values and not because of any error. Am I right?
> 
> Regards
> Kunal
> 
> On Sun, Sep 13, 2020 at 6:47 AM Gus Correa <gus at ldeo.columbia.edu <mailto:gus at ldeo.columbia.edu>> wrote:
> Hi Kunal
> 
> To try to nail down where, when, why it fails you could compile in debugging mode,
> ie. start fresh ('make CLEAN' in the build directory or just wipe that directory off) 
> and run gemake2 with the -devel flag (keep the other flags).
> Then, to increase verbosity add:
> debugLevel = 4,
> to the "data" namelist &PARM01,
> and increase the 
> monitorFreq 
> in &PARM03
> to one or a few time steps.
> The STDOUT.XXXX, and STDERR.XXXX files 
> may give a hint of what is going on (when, where, wny it fails).
> 
> I hope this helps,
> Gus Correa
> 
> On Sat, Sep 12, 2020 at 7:38 PM kunal madkaiker <kunal.madkaiker02 at gmail.com <mailto:kunal.madkaiker02 at gmail.com>> wrote:
> Dear All,
> 
> I am trying to simulate U,V currents circulation along the West Coast of India.
> I have a grid of 720 x 1560 with a high resolution of 1.45km x 1.45km, with 25 levels in the vertical from 0 to 2150m. I have set hFacMin=0.3 and hFacMinDz=10
> 
> But model blows up at the initial stage and I get the error: 
> Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG
> STOP MOM_IMPLICIT_R: error when solving 3-Diag problem.
> 
> I have tried changing viscAh from 1 to 1000 m2/s and viscAz from 0.02 to 0.001 m2/s. Also tried with viscAhgrid=0.1.
> I have defined the vertical levels keeping delZ(k+1)/delZ(k) < 1.4 ratio in mind. But the issue persists. Kindly advise. 
> Please let me know if any additional information is required from my side.
> 
> Regards
> Kunal
> 
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org <mailto:MITgcm-support at mitgcm.org>
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support <http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support>
> _______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org <mailto:MITgcm-support at mitgcm.org>
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support <http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support>
> <data><data.obcs><data.exf><STDOUT.0025>_______________________________________________
> MITgcm-support mailing list
> MITgcm-support at mitgcm.org
> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support

--
Jody Klymak    
http://ocean-physics.seos.uvic.ca/~jklymak/






-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20200913/3b55b921/attachment.html>


More information about the MITgcm-support mailing list