Include dependency graph for ptscotchDecomp.C:

Namespaces
	Foam
	Namespace for OpenFOAM.

Functions
	defineTypeNameAndDebug (ptscotchDecomp, 0)

	addToRunTimeSelectionTable (decompositionMethod, ptscotchDecomp, dictionary)

Detailed Description

Original source file ptscotchDecomp.C

From scotch forum:

By: Francois PELLEGRINI RE: Graph mapping 'strategy' string [ reply ] 2008-08-22 10:09 Strategy handling in Scotch is a bit tricky. In order not to be confused, you must have a clear view of how they are built. Here are some rules:

1- Strategies are made up of "methods" which are combined by means of "operators".

2- A method is of the form "m{param=value,param=value,...}", where "m" is a single character (this is your first error: "f" is a method name, not a parameter name).

3- There exist different sort of strategies : bipartitioning strategies, mapping strategies, ordering strategies, which cannot be mixed. For instance, you cannot build a bipartitioning strategy and feed it to a mapping method (this is your second error).

To use the "mapCompute" routine, you must create a mapping strategy, not a bipartitioning one, and so use stratGraphMap() and not stratGraphBipart(). Your mapping strategy should however be based on the "recursive bipartitioning" method ("b"). For instance, a simple (and hence not very efficient) mapping strategy can be :

"b{sep=f}"

which computes mappings with the recursive bipartitioning method "b", this latter using the Fiduccia-Mattheyses method "f" to compute its separators.

If you want an exact partition (see your previous post), try "b{sep=fx}".

However, these strategies are not the most efficient, as they do not make use of the multi-level framework.

To use the multi-level framework, try for instance:

"b{sep=m{vert=100,low=h,asc=f}x}"

The current default mapping strategy in Scotch can be seen by using the "-vs" option of program dgpart. It is, to date:

r { sep=m { asc=b { width=3, bnd=(d{pass=40,dif=1,rem=0,type=b}|) q{strat=f{move=80,pass=-1,bal=0.01,type=b}} x{sbbt=5,bal=0.05}, org=q{strat=f{move=80,pass=-1,bal=0.01,type=b}} x{sbbt=5,bal=0.05} }, low=q { strat= ( m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } |m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } ) }, seq=q { strat= ( m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } |m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } ) }, pass=5, vert=10000, rat=0.8 }, seq=r { job=t, bal=0.05, map=t, poli=S, sep= ( m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } |m { asc=b { bnd=(d{pass=40,type=b}|) f{move=80,pass=-1,bal=0.05,type=b}, org=f{move=80,pass=-1,bal=0.05,type=b}, width=3 }, low=h{pass=10} f{move=80,pass=-1,bal=0.05,type=b}, vert=80, rat=0.8 } ) }, bal=0.05 }

Note: writeGraph=true : writes out .dgr files for debugging. Run with e.g.

mpirun -np 4 dgpart 2 'region0_r.dgr'

r gets replaced by current processor rank
decompose into 2 domains

Definition in file ptscotchDecomp.C.

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Detailed Description