[CIG-SHORT] Intermediate Results

[Charles Williams]

Hmm.  It sounds to me as though you need to play with your parameters a bit.  I'm assuming you're using a frictional fault, which can definitely take a while to converge; however, you can do a few things to speed things up:

1.  Follow all of the suggestions Brad had from his previous e-mail.
2.  Make sure you have the highest quality mesh you can get.  Just one poorly formed element, especially on the fault, can really slow things down.
3.  Possibly try reducing your time step size.  It's possible that your load increment per timestep is too high for reasonable convergence.

When you have a chance, I would see if you can build PyLith from source on your cluster.  In addition to allowing parallel runs, this will let you take advantage of any machine-specific tools (e.g., optimized math libraries, etc.).

Let us know whether any of this helps.

Cheers,
Charles


On 7/03/2013, at 12:15 PM, BOK10 at pitt.edu wrote:

> Hi Charles,
> 
> I'm not running in parallel (I couldn't get the model to process in
> parallel on the cluster). Each time step takes ~80 minutes with loose
> tolerances, and about 2 hours for tighter tolerances.
> 
> The mesh itself is about 6,000 cells (2D). The faults have a 2 km
> discretization, and the boundaries have a 5 km discretization. Im using
> elasticplanestrain.
> 
> Bobby
> 
>> What sort of machine are you running on, and are you running in parallel?
>> I'm not sure what your problem size is, but 80 time steps shouldn't take
>> that long to run, unless it's a very nonlinear problem.  How large is your
>> mesh, and what sort of rheology are you using?
>> 
>> Cheers,
>> Charles
>> 
>> 
>> On 7/03/2013, at 11:36 AM, BOK10 at pitt.edu wrote:
>> 
>>> Hi Charles,
>>> 
>>> It takes pretty long for a simulation to finish processing, and I was
>>> hoping to split the simulation up into parts so I can come back to it
>>> later. It's not a necessity, but more a convenience issue.
>>> 
>>> I think I'll just continue on with running it overnight.
>>> 
>>> Thanks,
>>> Bobby
>>> 
>>> 
>>> 
>>>> Hi Bobby,
>>>> 
>>>> I'm not quite sure what you have in mind.  If you're running any sort
>>>> of
>>>> viscoelastic problem, you would need to save the entire state at the
>>>> end
>>>> of each run.  I don't see what benefit there would be from doing this,
>>>> since you would still need to finish each run to get all the state
>>>> variables at the end of each chunk, and then feed them into the next
>>>> simulation as initial state variables.
>>>> 
>>>> If your problem is completely elastic, I suppose you could run them in
>>>> the
>>>> way you're suggesting, and then use linear superposition to obtain the
>>>> final result.  What is your reason for wanting to break up the
>>>> simulation?
>>>> 
>>>> Cheers,
>>>> Charles
>>>> 
>>>> 
>>>> On 7/03/2013, at 11:22 AM, BOK10 at pitt.edu wrote:
>>>> 
>>>>> Is it possible to split a simulation into parts? I'm running my model
>>>>> for
>>>>> 400 years at 5 year time intervals, but is it possible to split it to
>>>>> 100
>>>>> year chunks and run them serially?
>>>>> 
>>>>> Bobby
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> _______________________________________________
>>>>> CIG-SHORT mailing list
>>>>> CIG-SHORT at geodynamics.org
>>>>> http://geodynamics.org/cgi-bin/mailman/listinfo/cig-short
>>>> 
>>>> Charles A. Williams
>>>> Scientist
>>>> GNS Science
>>>> 1 Fairway Drive, Avalon
>>>> PO Box 30368
>>>> Lower Hutt  5040
>>>> New Zealand
>>>> ph (office): 0064-4570-4566
>>>> fax (office): 0064-4570-4600
>>>> C.Williams at gns.cri.nz
>>>> 
>>>> 
>>>> Notice: This email and any attachments are confidential.
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>>> 
>>> 
>>> _______________________________________________
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>> 
>> Charles A. Williams
>> Scientist
>> GNS Science
>> 1 Fairway Drive, Avalon
>> PO Box 30368
>> Lower Hutt  5040
>> New Zealand
>> ph (office): 0064-4570-4566
>> fax (office): 0064-4570-4600
>> C.Williams at gns.cri.nz
>> 
>> _______________________________________________
>> CIG-SHORT mailing list
>> CIG-SHORT at geodynamics.org
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> 
> 
> _______________________________________________
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Charles A. Williams
Scientist
GNS Science
1 Fairway Drive, Avalon
PO Box 30368
Lower Hutt  5040
New Zealand
ph (office): 0064-4570-4566
fax (office): 0064-4570-4600
C.Williams at gns.cri.nz

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