scotchDecomp.C File Reference

Include dependency graph for scotchDecomp.C:

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Namespaces
	Foam
	Namespace for OpenFOAM.

Functions
void	scotchDecompLoad ()
	defineTypeNameAndDebug (scotchDecomp, 0)
	addToRunTimeSelectionTable (decompositionMethod, scotchDecomp, dictionary)

Detailed Description

Original source file scotchDecomp.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 gmap. It is, to date:

m { asc=b { width=3, bnd=d{pass=40, dif=1, rem=0} f{move=80, pass=-1, bal=0.01}, org=f{move=80,pass=-1,bal=0.01} }, low=r { job=t, bal=0.01, map=t, poli=S, sep= ( m { asc=b { bnd=f{move=120, pass=-1, bal=0.01, type=b}, org=f{move=120,pass=-1,bal=0.01,type=b}, width=3 }, low=h{pass=10} f{move=120,pass=-1,bal=0.01,type=b}, vert=120, rat=0.8 } |m { asc=b { bnd=f{move=120,pass=-1,bal=0.01,type=b}, org=f{move=120,pass=-1,bal=0.01,type=b}, width=3 }, low=h{pass=10} f{move=120,pass=-1,bal=0.01,type=b}, vert=120, rat=0.8 } ) }, vert=10000, rat=0.8, type=0 }

Note: instead of gmap run gpart <nProcs> -vs <grfFile> where <grfFile> can be obtained by running with 'writeGraph=true'

Definition in file scotchDecomp.C.

Function Documentation

scotchDecompLoad()

void scotchDecompLoad

(

)

Definition at line 134 of file scotchDecomp.C.