bandCompression.H

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    Copyright (C) 2011-2013 OpenFOAM Foundation
    Copyright (C) 2022 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
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InNamespace
    Foam

Description
    The bandCompression function renumbers the addressing such that the
    band of the matrix is reduced. The algorithm uses a simple search
    through the neighbour list in order of connectivity.

    See http://en.wikipedia.org/wiki/Cuthill-McKee_algorithm

SourceFiles
    bandCompression.C

\*---------------------------------------------------------------------------*/

#ifndef Foam_bandCompression_H
#define Foam_bandCompression_H

#include "labelList.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// Forward Declarations
template<class T> class CompactListList;

} // End namespace Foam


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{
namespace meshTools
{

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

//- Renumber (mesh) addressing to reduce the band of the matrix,
//- using the Cuthill-McKee algorithm.
//
//  \returns order in which the cells are to be visited (ordered to original)
labelList bandCompression(const CompactListList<label>& addressing);

//- Renumber (mesh) addressing to reduce the band of the matrix,
//- using the Cuthill-McKee algorithm.
//
//  \returns order in which the cells are to be visited (ordered to original)
labelList bandCompression(const labelListList& addressing);

//- Renumber with addressing in losort form (neighbour + start in neighbour),
//- using the Cuthill-McKee algorithm.
//
//  \returns order in which the cells are to be visited (ordered to original)
labelList bandCompression
(
    const labelUList& cellCells,
    const labelUList& offsets
);


} // End namespace meshTools
} // End namespace Foam


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

//- Forward to meshTools::bandCompression
inline labelList bandCompression(const labelListList& cellCellAddressing)
{
    return meshTools::bandCompression(cellCellAddressing);
}

//- Forward to meshTools::bandCompression
inline labelList bandCompression
(
    const labelUList& cellCells,
    const labelUList& offsets
)
{
    return meshTools::bandCompression(cellCells, offsets);
}

} // End namespace Foam


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //