[pozied]

Need help in solving this problem after I keyed in decomposePar

Selecting decompositionMethod simple


--> FOAM FATAL ERROR:
Wrong number of processor divisions in geomDecomp:
Number of domains : 2
Wanted decomposition : (5 2 1)

From function geomDecomp::geomDecomp(const dictionary& decompositionDict)
in file geomDecomp/geomDecomp.C at line 50.

FOAM exiting

Anyone knows what's the problem?

[alexeym]

Hi,

The error is explained in error message. You set number of subdomains (numberOfSubdomains) to 2, yet your simpleCoeffs dictionary contains

n           (5 2 1);

which corresponds to 10 subdomains (i.e. 5 divisions in X-direction and 2 in Y-direction).

[deepbandivadekar]

I have similar error.

--> FOAM FATAL ERROR: 
Wrong number of processor divisions in geomDecomp:
Number of domains    : 8
Wanted decomposition : (5 2 1)

    From function geomDecomp::geomDecomp(const dictionary& decompositionDict)
    in file geomDecomp/geomDecomp.C at line 50.

FOAM exiting

The decomposition matches total number of domains, yet the error. Why?

[deepbandivadekar]

Originally Posted by alexeym

Hi,

The error is explained in error message. You set number of subdomains (numberOfSubdomains) to 2, yet your simpleCoeffs dictionary contains

n           (5 2 1);

which corresponds to 10 subdomains (i.e. 5 divisions in X-direction and 2 in Y-direction).

Did you mean 8 subdomains ?

[kera]

Originally Posted by deepbandivadekar

Did you mean 8 subdomains ?

Hallo,

the way you defined your n "(5 2 1)" corresponds to 10 subdomains.

for 8 subdomains you need to define n as "(4 2 1) or (2 4 1) or (2 2 2) or ...".

Regards
Ricky

[deepbandivadekar]

Ohh! It's not the addition but multiplication.

This excerpt from the wiki for decomposePar clarified it.

method specifies the method used to decompose the domain. Available methods are:

• simple: it decomposes the domain in equal parts according in the directions specified in the corresponding subdictionary simpleCoeffs. For example, do decompose a case in 4 parts in the x direction, n has to be set to (4 1 1). To split the domain into 8 parts, 4 in the x direction and 2 in the z direction, n has to be set to (4 1 2).

Thnaks for this clarification. However, this raises the question why it is not addition according to this wiki explanation.

[arkn]

Originally Posted by deepbandivadekar

Ohh! It's not the addition but multiplication.

This excerpt from the wiki for decomposePar clarified it.
Thnaks for this clarification. However, this raises the question why it is not addition according to this wiki explanation.

Hi,
I'm not sure whether i understood your question correctly, but to me the wiki explanation seems just fine. Maybe imagining a chessboard might help: It's divided 8-fold in x- and y-direction, respectively. So the notation for n would be (8 8 1), multiplying to 64 squares (or hexahedra, accounting for z domain).


Hope, this helps someone.