[MITgcm-support] A very strange problem
m. r. schaferkotter
schaferk at bellsouth.net
Thu Jun 3 15:42:02 EDT 2010
again.
you might try reducing the time step.
http://forge.csail.mit.edu/pipermail/mitgcm-support/2004-January/001926.html
"advcfl_W_hf_max" is the vertical CFL number including the variable grid
resolution and most likely to be above 0.2 . If any of these numbers are
above 0.2 the model is close to or past being stable. In which case, you
need to reduce the time-step.
michael schaferkotter
On Jun 3, 2010, at 1:46 PM, Yuan Lian wrote:
> 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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>>
>>
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