metisLikeDecomp.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2017-2021 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.
 
    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
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    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
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Class
    Foam::metisLikeDecomp
 
Description
    Domain decomposition using METIS-like data structures.
 
    When run in parallel will collect the entire graph on to the master,
    decompose and send back.
 
SourceFiles
    metisLikeDecomp.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef metisLikeDecomp_H
#define metisLikeDecomp_H
 
#include "decompositionMethod.H"
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                       Class metisLikeDecomp Declaration
\*---------------------------------------------------------------------------*/
 
class metisLikeDecomp
:
    public decompositionMethod
{
protected:
 
    // Protected Data
 
        //- Coefficients for all derived methods
        const dictionary& coeffsDict_;
 
 
    // Protected Member Functions
 
        //- Serial and/or collect/distribute for parallel operation
        virtual label decomposeGeneral
        (
            const labelList& adjncy,
            const labelList& xadj,
            const List<scalar>& cellWeights,
            labelList& decomp
        ) const;
 
        //- Decomposition with metis-like parameters
        virtual label decomposeSerial
        (
            const labelList& adjncy,
            const labelList& xadj,
            const List<scalar>& cellWeights,
            labelList& decomp
        ) const = 0;
 
 
        //- No copy construct
        metisLikeDecomp(const metisLikeDecomp&) = delete;
 
        //- No copy assignment
        void operator=(const metisLikeDecomp&) = delete;
 
 
    // Constructors
 
        //- Construct for derived type name and decomposition dictionary.
        metisLikeDecomp
        (
            const word& derivedType,
            const dictionary& decompDict,
            int select = selectionType::NULL_DICT
        )
        :
            metisLikeDecomp(derivedType, decompDict, "", select)
        {}
 
        //- Construct for derived type name, decomposition dictionary
        //- and (optional) region name
        //  The default search for the coefficients will return dictionary::null
        //  on failure. This avoids a name clash of a metis "method" with the
        //  top level.
        metisLikeDecomp
        (
            const word& derivedType,
            const dictionary& decompDict,
            const word& regionName,
            int select = selectionType::NULL_DICT
        );
 
public:
 
    //- Destructor
    virtual ~metisLikeDecomp() = default;
 
 
    // Member Functions
 
        //- Inherit decompose from decompositionMethod
        using decompositionMethod::decompose;
 
        //- Return for every coordinate the wanted processor number.
        //  Uses the mesh connectivity (if needed).
        //  Weights get normalised so the minimum value is 1 before truncation
        //  to an integer so the weights should be multiples of the minimum
        //  value. The overall sum of weights might otherwise overflow.
        virtual labelList decompose
        (
            const polyMesh& mesh,
            const pointField& points,
            const scalarField& pointWeights
        ) const;
 
        //- Return for every coordinate the wanted processor number.
        //  Gets passed agglomeration map (from fine to coarse cells) and coarse
        //  cell location. Can be overridden by decomposers that provide this
        //  functionality natively.
        //  See note on weights above.
        virtual labelList decompose
        (
            const polyMesh& mesh,
            const labelList& agglom,
            const pointField& regionPoints,
            const scalarField& regionWeights
        ) const;
 
        //- Return for every coordinate the wanted processor number.
        //  Explicitly provided mesh connectivity.
        //  The connectivity is equal to mesh.cellCells() except for
        //  - in parallel the cell numbers are global cell numbers (starting
        //    from 0 at processor0 and then incrementing all through the
        //    processors)
        //  - the connections are across coupled patches
        //  See note on weights above.
        virtual labelList decompose
        (
            const labelListList& globalCellCells,
            const pointField& cellCentres,
            const scalarField& cellWeights
        ) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //