PPCG.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2019-2020 Mattijs Janssens
    Copyright (C) 2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
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
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
Class
    Foam::PPCG
 
Description
    Preconditioned pipelined conjugate gradient solver for symmetric
    lduMatrices using a run-time selectable preconditioner.
 
    Reference:
    \verbatim
        P. Ghysels, W. Vanroose.
        "Hiding global synchronization latency in the
         preconditioned Conjugate Gradient algorithm"
    \endverbatim
    and implementation details from
    \verbatim
        Paul Eller, William Gropp
        "Scalable Non-blocking Preconditioned Conjugate Gradient Methods"
    \endverbatim
 
SourceFiles
    PPCG.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef PPCG_H
#define PPCG_H
 
#include "lduMatrix.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                           Class PPCG Declaration
\*---------------------------------------------------------------------------*/
 
class PPCG
:
    public lduMatrix::solver
{
    // Private Member Functions
 
        //- Non-blocking version of sum(a*b), sum(a*c), sum(mag(sumMag))
        void gSumMagProd
        (
            FixedList<solveScalar, 3>& globalSum,
            const solveScalarField& a,
            const solveScalarField& b,
            const solveScalarField& c,
            const solveScalarField& sumMag,
            label& outstandingRequest,
            const label comm
        ) const;
 
        //- No copy construct
        PPCG(const PPCG&) = delete;
 
        //- No copy assignment
        void operator=(const PPCG&) = delete;
 
 
protected:
 
        //- CG solver. Operates either in conjugate-gradient mode or
        //- conjugate residual
        solverPerformance scalarSolveCG
        (
            solveScalarField& psi,
            const solveScalarField& source,
            const direction cmpt,
            const bool cgMode
        ) const;
 
 
public:
 
    //- Runtime type information
    TypeName("PPCG");
 
 
    // Constructors
 
        //- Construct from matrix components and solver controls
        PPCG
        (
            const word& fieldName,
            const lduMatrix& matrix,
            const FieldField<Field, scalar>& interfaceBouCoeffs,
            const FieldField<Field, scalar>& interfaceIntCoeffs,
            const lduInterfaceFieldPtrsList& interfaces,
            const dictionary& solverControls
        );
 
 
    //- Destructor
    virtual ~PPCG() = default;
 
 
    // Member Functions
 
        //- Solve the matrix with this solver
        virtual solverPerformance solve
        (
            scalarField& psi,
            const scalarField& source,
            const direction cmpt=0
        ) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //