[Arnoldinho]

Hi all,

is there any trick to get preservePatches in decomposePar working? When I put

preservePatches
(
bottom
);

at the end of my decomposeParDict and run the decomposition, following errors occurs:

Create mesh for region region0

Calculating distribution of cells
Keeping owner and neighbour of faces in patches
1
(
bottom
)
on same processor
Selecting decompositionMethod scotch
Selected 3144 faces whose owner and neighbour cell should be kept on the same processor
--> FOAM Warning :
From function min(const UList<Type>&)
in file /opt/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/FieldFunctions.C at line 342
empty field, returning zero

I guess because of this empty field, my 'bottom' patch is not kept at one processor, but is normally decomposed. So it does not have any effect! I have tested scotch and metis decomp. with 4-16 subdomains. I had a short look at FieldFunctions.C, but it does not really help me.

Any hints?

Arne

[darai]

Hi Arne,

Did you checked (for ex. in paraFoam used on one decomposed part) that the patch is really splitted? I am not experienced enough to be sure, but the warning doesn't say it splitted the patch... It is only saying something about problems with "min" function.

Martin.

[Arnoldinho]

Hi Martin,

I checked the decomposition on every processor (/processor*/paraFoam). It is definitely displayed as decomposed.
The min function warning only displays when using preservePatches, so I guess it has to do with it. So, just as a guess, the empty field is not holding any faces to keep on the same processor?

Is there anything missing in my decomposeParDict besides

numberOfSubdomains 8;

method scotch;

scotchCoeffs
{
processorWeights
(
1 1 1 1 1 1 1 1
);
}

manualCoeffs
{
dataFile "";
}

distributed no;

roots
(
);

preservePatches
(
bottom
);

BTW: I'm using OF 1.6-ext, but experienced the same with 1.7.x and 2.0.1

Arne