PrecisionAdaptor.H

/*---------------------------------------------------------------------------*\
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  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
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    Copyright (C) 2019-2021 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::PrecisionAdaptor

Description
    Conversion adaptor for Field/List that either wrap the input as a
    reference, or creates a temporary pointer and copies the values
    on construction/destruction.

    This provides, for example, automatic conversion between types
    for linear solvers able to run mixed precision.

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

#ifndef PrecisionAdaptor_H
#define PrecisionAdaptor_H

#include <algorithm>    // For std::copy
#include <type_traits>  // For std::is_same
#include "refPtr.H"
#include "Field.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
                    Class ConstPrecisionAdaptor Declaration
\*---------------------------------------------------------------------------*/

//- A const Field/List wrapper with possible data conversion
template<class Type, class InputType, template<class> class Container = Field>
class ConstPrecisionAdaptor
:
    public refPtr<Container<Type>>
{
    // Private Member Functions

        //- Set adaptor for different input, copying as required
        void setInput(const Container<InputType>& src)
        {
            if (std::is_same<Type, InputType>::value)
            {
                // Use reference directly
                this->cref(reinterpret_cast<const Container<Type>&>(src));