polynomialFunction.H

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/*---------------------------------------------------------------------------*\
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-------------------------------------------------------------------------------
    Copyright (C) 2011-2016 OpenFOAM Foundation
    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::polynomialFunction
 
Description
    Polynomial function representation
 
    \verbatim
        poly = logCoeff*log(x) + sum(coeffs[i]*x^i)
    \endverbatim
 
    where <tt> 0 <= i <= N </tt>
 
    - integer powers, starting at zero
    - \c value(x) to evaluate the poly for a given value
    - \c integrate(x1, x2) between two scalar values
    - \c integral() to return a new, integral coeff polynomial
      - increases the size (order)
    - \c integralMinus1() to return a new, integral coeff polynomial where
      the base poly starts at order -1
 
See also
    Foam::Polynomial for a templated implementation
 
SourceFiles
    polynomialFunction.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef polynomialFunction_H
#define polynomialFunction_H
 
#include "scalarList.H"
#include "Ostream.H"
#include "runTimeSelectionTables.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
// Forward Declarations
class polynomialFunction;
 
Istream& operator>>(Istream&, polynomialFunction& poly);
Ostream& operator<<(Ostream&, const polynomialFunction& poly);
 
/*---------------------------------------------------------------------------*\
                     Class polynomialFunction Declaration
\*---------------------------------------------------------------------------*/
 
class polynomialFunction
:
    private scalarList
{
    // Private Data
 
        //- Include the log term? - only activated using integralMinus1()
        bool logActive_;
 
        //- Log coefficient - only activated using integralMinus1()
        scalar logCoeff_;
 
 
    // Private Member Functions
 
        //- Return integral coefficients.
        //  Argument becomes zeroth element (constant of integration)
        static polynomialFunction cloneIntegral
        (
            const polynomialFunction&,
            const scalar intConstant = 0
        );
 
        //- Return integral coefficients when lowest order is -1.
        //  Argument becomes zeroth element (constant of integration)
        static polynomialFunction cloneIntegralMinus1
        (
            const polynomialFunction&,
            const scalar intConstant = 0
        );
 
        //- Check size is non-zero or trigger FatalErrot
        void checkSize() const;
 
 
public:
 
    //- Runtime type information
    TypeName("polynomialFunction");
 
 
    // Generated Methods: copy construct, copy assignment
 
 
    // Constructors
 
        //- Default construct as size 1 with coefficient == 0
        polynomialFunction();
 
        //- Construct a particular size, with all coefficients == 0
        explicit polynomialFunction(const label order);
 
        //- Construct from an initializer list of coefficients
        explicit polynomialFunction(std::initializer_list<scalar> coeffs);
 
        //- Construct from a list of coefficients
        explicit polynomialFunction(const UList<scalar>& coeffs);
 
        //- Construct from Istream
        explicit polynomialFunction(Istream& is);
 
 
    //- Destructor
    virtual ~polynomialFunction() = default;
 
 
    // Member Functions
 
        //- Non-zero number of coefficients
        using scalarList::empty;
 
        //- The number of coefficients
        using scalarList::size;
 
        //- Return coefficient at given index
        using scalarList::operator[];
 
 
        // Access
 
            //- True if the log term is active
            bool logActive() const;
 
            //- The log coefficient
            scalar logCoeff() const;
 
 
        // Evaluation
 
            //- Return polynomial value
            scalar value(const scalar x) const;
 
            //- Integrate between two values
            scalar integrate(const scalar x1, const scalar x2) const;
 
 
            //- Return integral coefficients.
            //  Argument becomes zeroth element (constant of integration)
            polynomialFunction integral
            (
                const scalar intConstant = 0
            ) const;
 
            //- Return integral coefficients when lowest order is -1.
            //  Argument becomes zeroth element (constant of integration)
            polynomialFunction integralMinus1
            (
                const scalar intConstant = 0
            ) const;
 
 
    // Member Operators
 
        //- Equality of coefficients, and logCoeff (if active)
        bool operator==(const polynomialFunction& rhs) const;
 
        bool operator!=(const polynomialFunction& rhs) const
        {
            return !operator==(rhs);
        }
 
        polynomialFunction& operator+=(const polynomialFunction&);
        polynomialFunction& operator-=(const polynomialFunction&);
 
        polynomialFunction& operator*=(const scalar);
        polynomialFunction& operator/=(const scalar);
 
 
    // IOstream Operators
 
    friend Istream& operator>>(Istream&, polynomialFunction& poly);
    friend Ostream& operator<<(Ostream&, const polynomialFunction& poly);
};
 
 
// * * * * * * * * * * * * * * * Global Operators  * * * * * * * * * * * * * //
 
polynomialFunction operator+
(
    const polynomialFunction&,
    const polynomialFunction&
);
 
 
polynomialFunction operator-
(
    const polynomialFunction&,
    const polynomialFunction&
);
 
 
polynomialFunction operator*
(
    const scalar,
    const polynomialFunction&
);
 
 
polynomialFunction operator/
(
    const scalar,
    const polynomialFunction&
);
 
 
polynomialFunction operator*
(
    const polynomialFunction&,
    const scalar
);
 
 
polynomialFunction operator/
(
    const polynomialFunction&,
    const scalar
);
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //