Opened 3 weeks ago

Last modified 10 days ago

#2386 new help

EG_BICGSTAB_MIXED_PREC error in forecast stage of nesting suite

Reported by: nx902220 Owned by: um_support
Priority: normal Component: UM Model
Keywords: convergence, BICGSTAB Cc:
Platform: Monsoon2 UM Version: 10.5



I am running a nesting suite u-au206 and in the first nest at the ukv_um_fcst stage it fails with job.err:

???!!!???!!!???!!!???!!!???!!! ERROR ???!!!???!!!???!!!???!!!???!!!
? Error code: 11
? Error from routine: EG_BICGSTAB_MIXED_PREC
? Error message: Convergence failure in BiCGstab, omg is too small
? Error from processor: 256
? Error number: 21

I cannot find the cause of this issue (I have a colleague who has also run the suite run the suite and experienced the same problem and could not find a solution). The suite runs for another case study date 04-05-2016. But not this one 11-06-2015.

All I have changed between model runs is the case study date in rose-app.conf and the paths to the reanalysis data in retrieve_ukv_data

If you could investigate this for me I would be very appreciative.

Best wishes,


Change History (2)

comment:1 Changed 10 days ago by willie

Hi Lewis,

This is failing at the second time step.

Normally this type of error is corrected by reducing the time step. I have tried 30 sec and 15 sec and these haven't worked. I have also tried increasing the number of convection calls per time step to three, to no avail. I have used a MOCI tool to perturb the temperature field in the start dump and this has not succeeded. I then tried the previous day 2015-06-10, but it too fails after two time steps.

This may take some time to solve.


comment:2 Changed 10 days ago by willie

  • Keywords convergence, BICGSTAB added
  • Platform set to Monsoon2
  • UM Version changed from <select version> to 10.5
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