ptscotchDecomp.H

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    Copyright (C) 2018-2023 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.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    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::ptscotchDecomp
 
Description
    PTScotch domain decomposition.
 
    For the main details about how to define the strategies, see scotchDecomp.
 
    Coefficients dictionary: \a scotchCoeffs, \a coeffs.
 
    Nonetheless, when decomposing in parallel, using <tt>writeGraph=true</tt>
    will write out \c .dgr files for debugging. For example, use these files
    with \c dgpart as follows:
 
    \verbatim
    mpirun -np 4 dgpart 2 'region0_%r.dgr'
    \endverbatim
 
    where:
      - %r gets replaced by current processor rank
      - it will decompose into 2 domains
 
See also
    Foam::scotchDecomp
 
SourceFiles
    ptscotchDecomp.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef Foam_ptscotchDecomp_H
#define Foam_ptscotchDecomp_H
 
#include "decompositionMethod.H"
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                       Class ptscotchDecomp Declaration
\*---------------------------------------------------------------------------*/
 
class ptscotchDecomp
:
    public decompositionMethod
{
    // Private Data
 
        //- Original coefficients for this method
        dictionary coeffsDict_;
 
        //- Output path and name for optional grf file.
        mutable fileName graphPath_;
 
 
    // Private Member Functions
 
        //- Decompose. Handles size 0 arrays
        label decompose
        (
            const labelList& adjncy,
            const labelList& xadj,
            const List<scalar>& cWeights,
            labelList& decomp
        ) const;
 
public:
 
    // Generated Methods
 
        //- No copy construct
        ptscotchDecomp(const ptscotchDecomp&) = delete;
 
        //- No copy assignment
        void operator=(const ptscotchDecomp&) = delete;
 
 
    //- Runtime type information
    TypeName("ptscotch");
 
 
    // Constructors
 
        //- Construct with number of domains (no coefficients or constraints)
        explicit ptscotchDecomp(const label numDomains);
 
        //- Construct given decomposition dictionary and optional region name
        explicit ptscotchDecomp
        (
            const dictionary& decompDict,
            const word& regionName = ""
        );
 
 
    //- Destructor
    virtual ~ptscotchDecomp() = default;
 
 
    // Member Functions
 
        //- Knows about coupled boundaries
        virtual bool parallelAware() const
        {
            return true;
        }
 
        //- Inherit decompose from decompositionMethod
        using decompositionMethod::decompose;
 
        //- Return for every coordinate the wanted processor number.
        //  Use the mesh connectivity (if needed).
        //  See note on weights in scotchDecomp.H
        virtual labelList decompose
        (
            const polyMesh& mesh,
            const pointField& points = pointField::null(),
            const scalarField& pointWeights = scalarField::null()
        ) 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 in scotchDecomp.H
        virtual labelList decompose
        (
            const polyMesh& mesh,
            const labelList& agglom,
            const pointField& agglomPoints,
            const scalarField& agglomWeights = scalarField::null()
        ) const;
 
        //- Return for every coordinate the wanted processor number.
        virtual labelList decompose
        (
            const CompactListList<label>& globalCellCells,
            const pointField& cc = pointField::null(),
            const scalarField& cWeights = scalarField::null()
        ) 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 in scotchDecomp.H
        virtual labelList decompose
        (
            const labelListList& globalCellCells,
            const pointField& cc = pointField::null(),
            const scalarField& cWeights = scalarField::null()
        ) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //