linearEqn.H

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    Copyright (C) 2020 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

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Class
    Foam::linearEqn

Description
    Container to encapsulate various operations for
    linear equation of the forms with real coefficients:

    \f[
        a*x + b = 0
          x + B = 0
    \f]

See also
    Test-linearEqn.C

SourceFiles
    linearEqnI.H

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

#ifndef Foam_linearEqn_H
#define Foam_linearEqn_H

#include "Roots.H"

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

namespace Foam
{

/*---------------------------------------------------------------------------*\
                         Class linearEqn Declaration
\*---------------------------------------------------------------------------*/

class linearEqn
:
    public VectorSpace<linearEqn, scalar, 2>
{
public:

    //- Component labeling enumeration
    enum components { A, B };


    // Constructors

        //- Default construct
        linearEqn() = default;

        //- Construct initialized to zero
        inline linearEqn(const Foam::zero);

        //- Construct from components
        inline linearEqn(const scalar a, const scalar b);


    // Member Functions

    // Access

        scalar a() const noexcept { return this->v_[A]; }
        scalar b() const noexcept { return this->v_[B]; }

        scalar& a() noexcept { return this->v_[A]; }
        scalar& b() noexcept { return this->v_[B]; }


    // Evaluate

        //- Evaluate the linear equation at x
        inline scalar value(const scalar x) const;

        //- Evaluate the derivative of the linear equation at x
        inline scalar derivative(const scalar x) const;

        //- Estimate the error of evaluation of the linear equation at x
        inline scalar error(const scalar x) const;

        //- Return the real root of the linear equation
        inline Roots<1> roots() const;
};


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

} // End namespace Foam

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

#include "linearEqnI.H"

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

#endif

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