The preservePatches Option in decomposePar
 

Dear Foamers,

It seems that the preservePatches option of the decomposePar utility actually means that for all faces of a preserved patch have the owner and neighbor on the same processor (as commented in code)?

What if I want to preserve a complete patch (or two identical patches) in one processor using the scotch method, is it doable?

I can do it with the simple method but I thought there maybe a lazier way to do it and to somehow preserve processor weights? :)

Best regards
Hisham

Dear Hisham,

I'm also trying to get a certain patch preserved. PreservePatches doesn't seem to work right now so I'm looking forward to the result of your 'experiment'. Did you also try to use manual instead of scotch?

Regards,

Ralph

Greetings to both!

There was a bug report on this that hasn't been closed yet: http://www.openfoam.org/mantisbt/view.php?id=387

Best regards,
Bruno

Dear Bruno, thanks for your reply.

I tried to test this option yesterday (OF2.1) but unfortunately I don't have cyclic patches so this option doesn't seem to work for me or am I wrong?

Would there be another way to preserve non-cyclic patches? Maybe a manual decomposition?

Ralph

Hi Ralph,

I don't have much time to go into details, so here is the summary:

1. Use the decomposition method you wish to use and add to the decomposePar command the argument described in the help:
   
   Code:

   ---

   $ decomposePar -help

Usage: decomposePar [OPTIONS]
options:
#...
  -cellDist        write cell distribution as a labelList - for use with
                    'manual' decomposition method or as a volScalarField for
                    post-processing.
#...

   ---

2. Look into the main example file for the dictionary at "applications/utilities/parallelProcessing/decomposePar/decomposeParDict".
3. Test if the manual decomposition actually works.
4. Manipulate the "weights" as if you manipulating a field, namely by using setSet or topoSet, along with setFields. For drawing ideas, run the following commands for tracking down examples:
   
   Code:

   ---

   find $FOAM_TUTORIALS -name topoSetDict
find $FOAM_TUTORIALS -name setFieldsDict

   ---

:confused: Looks like you were already half-way there already:

• http://www.cfd-online.com/Forums/ope...r-utility.html post #8
• http://www.cfd-online.com/Forums/ope...computing.html post #3

Best regards,
Bruno