Difference between revisions of "Tips and Tricks"

(Unstable WRF simulation)
 
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[[Category:WRF]]
 
[[Category:WRF]]
  
1. If you notice that the WRF model has become unstable, you should consider to make the following changes in the namelis.input file:
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== Unstable WRF simulation ==
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If you notice that the WRF model has become unstable, you should consider making the following changes in the namelist.input file:
  
(a) reduce the time-step; and/or
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# reduce the time-step; and/or
 +
# set w_damping to 1; and/or
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# set epssm (0.1 by default) to a higher value (e.g. 0.3)
  
(b) set w_damping to 1; and/or
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The changes above indeed improved the stabilities in our case.
  
(c) set epssm (0.1 by default) to a higher value (e.g. 0.3)
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You can also explore the following ideas:
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# reduce the total number of processors
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# change the decomposition through nproc_x and nproc_y options
 +
# reduce the level of optimisation via re-compilation
  
The changes above indeed improves the stabilities in our case.
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== Runtime segmentation error ==
 +
WRF will always crash with a segmentation error when compiled without debugging information.
  
2. If there is segmentation error in runtime, you can add following line to your PBS job batch script and see if this works:
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But you should make sure, you always run WRF with an unlimited stacksize. This should be set in your run script.
 
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:For TCSH
limit stacksize unlimited (for TCSH)
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<code>
or
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limit stacksize unlimited
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</code>
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:For BASH
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<code>
 
ulimit -s unlimited (for BASH)
 
ulimit -s unlimited (for BASH)
 +
</code>
  
**If you have some tricks that can help WRF users in our community and hope that they could be included on this page, please email climate_help@nf.nci.org.au.'''
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'''If you have some tricks that can help WRF users in our community and hope that they could be included on this page, please email cws_help@nci.org.au.'''

Latest revision as of 22:41, 11 December 2019

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Unstable WRF simulation

If you notice that the WRF model has become unstable, you should consider making the following changes in the namelist.input file:

  1. reduce the time-step; and/or
  2. set w_damping to 1; and/or
  3. set epssm (0.1 by default) to a higher value (e.g. 0.3)

The changes above indeed improved the stabilities in our case.

You can also explore the following ideas:

  1. reduce the total number of processors
  2. change the decomposition through nproc_x and nproc_y options
  3. reduce the level of optimisation via re-compilation

Runtime segmentation error

WRF will always crash with a segmentation error when compiled without debugging information.

But you should make sure, you always run WRF with an unlimited stacksize. This should be set in your run script.

For TCSH

limit stacksize unlimited

For BASH

ulimit -s unlimited (for BASH)

If you have some tricks that can help WRF users in our community and hope that they could be included on this page, please email cws_help@nci.org.au.