[MITgcm-support] A very strange problem

Thu Jun 3 14:46:45 EDT 2010

The number doesn't seem to be very large ...

Maybe there is truncating error that makes the "divide by zero" occur?
Have you checked if the initial data files been generated/or read by
MITgcm correctly, i.e., all initial data files use double precision?

Yuan

On 6/3/10 11:28 AM, m. r. schaferkotter wrote:
> try reducing the time step as
>
> (PID.TID 0000.0001) %MON advcfl_W_hf_max = 2.2335820994742E-01
>
> could indicate a smaller time step.
>
>
> On Jun 3, 2010, at 4:08 AM, ouc.edu.cn wrote:
>
>> Hi Jean-Michel,
>> Thank you for your reply.
>> From the 'STDOUT.00xx' files I'm sure the model didn't blow up, cause
>> everything looks nomal, and all these 32 files are kind of the same
>> and contain almost the same information. Below is the information of
>> the last two iterations:
>> (PID.TID 0000.0001) // Begin MONITOR dynamic field statistics
>> (PID.TID 0000.0001) //
>> =======================================================
>> (PID.TID 0000.0001) %MON time_tsnumber = 316
>> (PID.TID 0000.0001) %MON time_secondsf = 3.9500000000000E+03
>> (PID.TID 0000.0001) %MON dynstat_eta_max = 4.2351103155441E-01
>> (PID.TID 0000.0001) %MON dynstat_eta_min = -2.9095841140222E-01
>> (PID.TID 0000.0001) %MON dynstat_eta_mean = 2.2266055703883E-05
>> (PID.TID 0000.0001) %MON dynstat_eta_sd = 2.4506462290779E-03
>> (PID.TID 0000.0001) %MON dynstat_eta_del2 = 1.3655537149458E-03
>> (PID.TID 0000.0001) %MON dynstat_uvel_max = 2.9081925049449E+00
>> (PID.TID 0000.0001) %MON dynstat_uvel_min = -2.3945333213539E+00
>> (PID.TID 0000.0001) %MON dynstat_uvel_mean = -5.9096408449438E-05
>> (PID.TID 0000.0001) %MON dynstat_uvel_sd = 3.4343631952692E-03
>> (PID.TID 0000.0001) %MON dynstat_uvel_del2 = 4.7379871670678E-03
>> (PID.TID 0000.0001) %MON dynstat_vvel_max = 2.5933981864330E+00
>> (PID.TID 0000.0001) %MON dynstat_vvel_min = -3.2231876263118E+00
>> (PID.TID 0000.0001) %MON dynstat_vvel_mean = 1.4348687349928E-06
>> (PID.TID 0000.0001) %MON dynstat_vvel_sd = 1.2624775236425E-03
>> (PID.TID 0000.0001) %MON dynstat_vvel_del2 = 3.8178362135143E-03
>> (PID.TID 0000.0001) %MON dynstat_wvel_max = 2.9846705628259E-01
>> (PID.TID 0000.0001) %MON dynstat_wvel_min = -2.3853942232519E-01
>> (PID.TID 0000.0001) %MON dynstat_wvel_mean = -2.1033468915427E-09
>> (PID.TID 0000.0001) %MON dynstat_wvel_sd = 1.9417325836487E-04
>> (PID.TID 0000.0001) %MON dynstat_wvel_del2 = 9.3761000810601E-04
>> (PID.TID 0000.0001) %MON dynstat_theta_max = 3.7963165120273E+01
>> (PID.TID 0000.0001) %MON dynstat_theta_min = -2.1436513114643E+01
>> (PID.TID 0000.0001) %MON dynstat_theta_mean = 5.9453514759821E+00
>> (PID.TID 0000.0001) %MON dynstat_theta_sd = 6.2570503287055E+00
>> (PID.TID 0000.0001) %MON dynstat_theta_del2 = 2.5262750966653E-02
>> (PID.TID 0000.0001) %MON dynstat_salt_max = 3.8107582424356E+01
>> (PID.TID 0000.0001) %MON dynstat_salt_min = 0.0000000000000E+00
>> (PID.TID 0000.0001) %MON dynstat_salt_mean = 3.4534555031168E+01
>> (PID.TID 0000.0001) %MON dynstat_salt_sd = 1.2887956836604E-01
>> (PID.TID 0000.0001) %MON dynstat_salt_del2 = 2.5964953005350E-03
>> (PID.TID 0000.0001) %MON advcfl_uvel_max = 1.4540962524725E-01
>> (PID.TID 0000.0001) %MON advcfl_vvel_max = 4.0289845328898E-02
>> (PID.TID 0000.0001) %MON advcfl_wvel_max = 2.1666787542532E-01
>> (PID.TID 0000.0001) %MON advcfl_W_hf_max = 2.2335820994742E-01
>> (PID.TID 0000.0001) %MON pe_b_mean = 1.2621239225557E-08
>> (PID.TID 0000.0001) %MON ke_max = 4.6011781196852E+00
>> (PID.TID 0000.0001) %MON ke_mean = 4.6615962365024E-06
>> (PID.TID 0000.0001) %MON ke_vol = 9.9365095001242E+17
>> (PID.TID 0000.0001) %MON vort_r_min = -7.2511662603239E-03
>> (PID.TID 0000.0001) %MON vort_r_max = 6.4558430600778E-03
>> (PID.TID 0000.0001) %MON vort_a_mean = 5.0662999065604E-05
>> (PID.TID 0000.0001) %MON vort_a_sd = 7.4966761920324E-07
>> (PID.TID 0000.0001) %MON vort_p_mean = 7.3612614840296E-05
>> (PID.TID 0000.0001) %MON vort_p_sd = 5.9336048842539E-05
>> (PID.TID 0000.0001) %MON surfExpan_theta_mean = -9.9981862111201E-08
>> (PID.TID 0000.0001) %MON surfExpan_salt_mean = -1.1922103976760E-07
>> (PID.TID 0000.0001) //
>> =======================================================
>> (PID.TID 0000.0001) // End MONITOR dynamic field statistics
>> (PID.TID 0000.0001) //
>> =======================================================
>> cg2d: Sum(rhs),rhsMax = -4.85042010003101E+00 3.71869645807112E-02
>> (PID.TID 0000.0001) cg2d_init_res = 4.74339332785140E-02
>> (PID.TID 0000.0001) cg2d_iters = 126
>> (PID.TID 0000.0001) cg2d_res = 9.36545477468715E-14
>> cg3d: Sum(rhs),rhsMax = 3.24606069488422E-10 1.20245356700100E-09
>> (PID.TID 0000.0001) cg3d_init_res = 1.02771503214190E-01
>> (PID.TID 0000.0001) cg3d_iters = 20
>> (PID.TID 0000.0001) cg3d_res = 3.71423006414093E-03
>> (PID.TID 0000.0001) //
>> =======================================================
>> (PID.TID 0000.0001) // Begin MONITOR dynamic field statistics
>> (PID.TID 0000.0001) //
>> =======================================================
>> (PID.TID 0000.0001) %MON time_tsnumber = 317
>> (PID.TID 0000.0001) %MON time_secondsf = 3.9625000000000E+03
>> (PID.TID 0000.0001) %MON dynstat_eta_max = 4.2644526849910E-01
>> And I can not see anything abnormal,(I increased cg3dMaxIters to a
>> much larger number this afternoon, and the model even stoped with
>> less time stops).
>> In sum, according to the STDOUT files, the model did not blowup, but
>> the machine did give an error message, i.e.,
>> [node7:03388] Signal: Floating point exception (8)
>> [node7:03388] Signal code: Floating point divide-by-zero (3)
>> in file "my_job.o1562"
>> This problem never happened when I set coriolis force f0=0, and
>> initial V velocity to zero. However, when I changed either of these
>> two parameters, the problem appears. I'm really confused,,, Do you
>> think there is a bug in this model or something ?
>> Best Wishes,
>> Dwight
>>
>>
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