scalarAndError.H

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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
    the Free Software Foundation, either version 3 of the License, or
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    You should have received a copy of the GNU General Public License
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Class
    Foam::scalarAndError
 
Description
    Class to encapsulate a scalar value and an associated round-off error.
    The error is tracked through operations performed between scalarAndError
    variables.
 
SourceFiles
    scalarAndErrorI.H
 
\*---------------------------------------------------------------------------*/
 
#ifndef scalarAndError_H
#define scalarAndError_H
 
#include "scalar.H"
#include "zero.H"
#include "contiguous.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
 
/*---------------------------------------------------------------------------*\
                        Class scalarAndError Declaration
\*---------------------------------------------------------------------------*/
 
class scalarAndError
{
public:
 
    //- Component type
    typedef scalarAndError cmptType;
 
 
    // Member constants
 
        //- Dimensionality of space
        static const direction dim = 3;
 
        //- Rank of scalarAndError is 0
        static const direction rank = 0;
 
        //- Number of components in scalarAndError is 1
        static const direction nComponents = 1;
 
 
    // Public Data
 
        //- The value
        scalar value;
 
        //- The error
        scalar error;
 
 
    // Constructors
 
        //- Default construct
        inline scalarAndError()
        {}
 
        //- Construct zero
        inline scalarAndError(const zero&)
        :
            value(scalar(0)),
            error(scalar(0))
        {}
 
        //- Construct from a scalar
        inline scalarAndError(const scalar v)
        :
            value(v),
            error(small*mag(v))
        {}
 
        //- Construct from a scalar and an error
        inline scalarAndError(const scalar v, const scalar e)
        :
            value(v),
            error(e)
        {}
 
 
    // Member Operators
 
        //- Negate
        inline scalarAndError operator-() const
        {
            return scalarAndError(- value, error);
        }
 
        //- Add another scalar-and-error to this one
        inline void operator+=(const scalarAndError& sae)
        {
            value += sae.value;
            error += mag(sae.error);
        }
 
        //- Subtract another scalar-and-error from this one
        inline void operator-=(const scalarAndError& sae)
        {
            this->operator+=(- sae);
        }
 
        //- Multiply another scalar-and-error with this one
        inline void operator*=(const scalarAndError& sae)
        {
            error = mag(value*error) + mag(sae.value*sae.error);
            value *= sae.value;
        }
 
        //- Divide this scalar-and-error by another
        inline void operator/=(const scalarAndError& sae)
        {
            error = mag(error/sae.value) + mag(sae.error/sqr(sae.value));
            value /= sae.value;
        }
};
 
 
//- Data associated with the scalar-and-error type is contiguous
template<>
inline bool contiguous<scalarAndError>() { return true; }
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#include "scalarAndErrorI.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //