dimensionSet.H

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    Copyright (C) 2017-2023 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

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Class
    Foam::dimensionSet

Description
    Dimension set for the base types, which can be used to implement
    rigorous dimension checking for algebraic manipulation.

    The dimensions are specified in the following order
    (SI units for reference only):
    \table
        Property    | SI Description        | SI unit
        MASS        | kilogram              | \c kg
        LENGTH      | metre                 | \c m
        TIME        | second                | \c s
        TEMPERATURE | Kelvin                | \c K
        MOLES       | mole                  | \c mol
        CURRENT     | Ampere                | \c A
        LUMINOUS_INTENSITY | Candela        | \c cd
    \endtable

SourceFiles
    dimensionSet.C
    dimensionSetIO.C

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

#ifndef Foam_dimensionSet_H
#define Foam_dimensionSet_H

#include "bool.H"
#include "dimensionedScalarFwd.H"
#include "className.H"
#include "scalarField.H"
#include "PtrList.H"
#include "HashTable.H"
#include "IOobjectOption.H"

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

namespace Foam
{

// Forward Declarations
class dictionary;
class dimensionSet;
class dimensionSets;

/*---------------------------------------------------------------------------*\
                        Class dimensionSet Declaration
\*---------------------------------------------------------------------------*/

class dimensionSet
{
public:

    //- The array of dimension exponents
    typedef FixedList<scalar,7> list_type;


    // Member Constants

        //- There are 7 base dimensions
        static constexpr int nDimensions = 7;

        //- Enumeration for the dimension exponents
        enum dimensionType
        {
            MASS,               
            LENGTH,             
            TIME,               
            TEMPERATURE,        
            MOLES,              
            CURRENT,            
            LUMINOUS_INTENSITY  
        };


    // Static Data Members

        //- Tolerance for 'small' exponents, for near-zero rounding
        static const scalar smallExponent;


private:

    // Private Data

        //- The array of dimension exponents
        list_type exponents_;


    // Private Classes

        class tokeniser
        {
            // Private Data

                Istream& is_;

                List<token> tokens_;

                label start_;

                label size_;


            // Private Member Functions

                void push(const token& t);

                token pop();

                void unpop(const token& t);

        public:

            // Constructors

                 explicit tokeniser(Istream& is);


            // Member Functions

                Istream& stream() noexcept { return is_; }

                bool hasToken() const;

                token nextToken();

                void putBack(const token&);

                void splitWord(const word&);

                static bool valid(char c);

                static label priority(const token& t);
        };


        //- Reset exponents to nearest integer if close to it.
        //  Handles reading with insufficient precision.
        void round(const scalar tol);

        dimensionedScalar parse
        (
            const label lastPrior,
            tokeniser& tis,
            const HashTable<dimensionedScalar>&
        ) const;


public:

    // Declare name of the class and its debug switch
    ClassName("dimensionSet");


    // Static Functions

        //- Turn dimension checking on/off.
        //  \return the previous value
        static bool checking(bool on) noexcept
        {
            bool old(debug);
            debug = static_cast<int>(on);
            return old;
        }

        //- True if dimension checking is enabled (the usual default)
        static bool checking() noexcept
        {
            return static_cast<bool>(debug);
        }


    // Constructors

        //- Default construct (dimensionless).
        dimensionSet();

        //- Construct from exponents for the first five or all seven dimensions
        dimensionSet
        (
            const scalar mass,
            const scalar length,
            const scalar time,
            const scalar temperature,
            const scalar moles,
            const scalar current = 0,
            const scalar luminousIntensity = 0
        );

        //- Construct from exponents for all seven dimensions
        dimensionSet(const FixedList<scalar,7>& dimensions);

        //- Copy construct
        dimensionSet(const dimensionSet& ds);

        //- Construct from dictionary entry (usually "dimensions")
        //  Dimensionless if non-mandatory and not found.
        dimensionSet
        (
            const word& entryName,  
            const dictionary& dict,
            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
        );

        //- Construct and return a clone
        autoPtr<dimensionSet> clone() const
        {
            return autoPtr<dimensionSet>::New(*this);
        }

        //- Construct from Istream
        explicit dimensionSet(Istream& is);


    // Member Functions

        //- Return true if it is dimensionless
        bool dimensionless() const;

        //- Const access to the exponents as a list
        const FixedList<scalar,7>& values() const noexcept;

        //- Non-const access to the exponents as a list
        FixedList<scalar,7>& values() noexcept;

        //- Clear exponents - resets to be dimensionless
        void clear();

        //- Copy assign the exponents from the dimensionSet
        void reset(const dimensionSet& ds);


    // IO

        //- Update the dimensions from dictionary entry.
        //- FatalIOError if it is found and the number of tokens is incorrect,
        //- or it is mandatory and not found.
        //
        //  \return true if the entry was found.
        bool readEntry
        (
            const word& entryName,      
            const dictionary& dict,     
            IOobjectOption::readOption readOpt = IOobjectOption::MUST_READ
        );

        //- Update the dimensions from dictionary entry.
        //- FatalIOError if it is found and the number of tokens is incorrect,
        //- or it is mandatory and not found.
        //
        //  \return true if the entry was found.
        bool readIfPresent
        (
            const word& entryName,      
            const dictionary& dict      
        )
        {
            return readEntry(entryName, dict, IOobjectOption::READ_IF_PRESENT);
        }

        //- Read using provided units, return scaling in multiplier.
        //- Used only in initial parsing
        Istream& read
        (
            Istream& is,
            scalar& multiplier,
            const dictionary&
        );

        //- Read using provided units, return scaling in multiplier
        Istream& read
        (
            Istream& is,
            scalar& multiplier,
            const HashTable<dimensionedScalar>&
        );

        //- Read using system units, return scaling in multiplier
        Istream& read
        (
            Istream& is,
            scalar& multiplier
        );

        //- Write using provided write units, return scaling in multiplier
        Ostream& write
        (
            Ostream& os,
            scalar& multiplier,
            const dimensionSets& writeUnits
        ) const;

        //- Write using system units, return scaling in multiplier
        Ostream& write(Ostream& os, scalar& multiplier) const;


    // Member Operators

        scalar operator[](const dimensionType) const;
        scalar& operator[](const dimensionType);

        scalar operator[](const label) const;
        scalar& operator[](const label);

        bool operator==(const dimensionSet&) const;
        bool operator!=(const dimensionSet&) const;

        bool operator=(const dimensionSet&) const;

        bool operator+=(const dimensionSet&) const;
        bool operator-=(const dimensionSet&) const;
        bool operator*=(const dimensionSet&);
        bool operator/=(const dimensionSet&);
};


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

// IOstream Operators

Istream& operator>>(Istream& is, dimensionSet& ds);
Ostream& operator<<(Ostream& os, const dimensionSet& ds);


// Global Functions

dimensionSet min(const dimensionSet& a, const dimensionSet& b);
dimensionSet max(const dimensionSet& a, const dimensionSet& b);
dimensionSet clamp(const dimensionSet& a, const dimensionSet& range);
dimensionSet lerp(const dimensionSet& a, const dimensionSet& b);

dimensionSet cmptMultiply(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet cmptDivide(const dimensionSet& ds1, const dimensionSet& ds2);


dimensionSet pow(const dimensionSet& ds, const scalar p);
dimensionSet pow(const dimensionSet& ds, const dimensionedScalar& p);

dimensionSet sqr(const dimensionSet& ds);
dimensionSet pow2(const dimensionSet& ds);
dimensionSet pow3(const dimensionSet& ds);
dimensionSet pow4(const dimensionSet& ds);
dimensionSet pow5(const dimensionSet& ds);
dimensionSet pow6(const dimensionSet& ds);
dimensionSet pow025(const dimensionSet& ds);

dimensionSet sqrt(const dimensionSet& ds);
dimensionSet cbrt(const dimensionSet& ds);

dimensionSet magSqr(const dimensionSet& ds);
dimensionSet mag(const dimensionSet& ds);
dimensionSet sign(const dimensionSet&);
dimensionSet pos(const dimensionSet&);
dimensionSet pos0(const dimensionSet&);
dimensionSet neg(const dimensionSet&);
dimensionSet neg0(const dimensionSet&);
dimensionSet posPart(const dimensionSet&);
dimensionSet negPart(const dimensionSet&);

//- The dimensionSet inverted
dimensionSet inv(const dimensionSet& ds);

//- Check the argument is dimensionless (for transcendental functions)
dimensionSet trans(const dimensionSet& ds);

//- Arguments need the same dimensions. Return dimensionless.
dimensionSet atan2(const dimensionSet& ds1, const dimensionSet& ds2);

//- Arguments need the same dimensions. Does not change the dimension.
dimensionSet hypot(const dimensionSet& ds1, const dimensionSet& ds2);

//- Arguments need the same dimensions. Does not change the dimension.
dimensionSet stabilise(const dimensionSet& ds1, const dimensionSet& ds2);

//- Return the argument; transformations do not change the dimensions
dimensionSet transform(const dimensionSet& ds);

//- Return the argument; transformations do not change the dimensions
dimensionSet invTransform(const dimensionSet& ds);


// Global Operators

//- The dimensionSet inverted
dimensionSet operator~(const dimensionSet& ds);

//- Unary negation.
dimensionSet operator-(const dimensionSet& ds);

dimensionSet operator+(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator-(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator*(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator/(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator&(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator^(const dimensionSet& ds1, const dimensionSet& ds2);
dimensionSet operator&&(const dimensionSet& ds1, const dimensionSet& ds2);


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

} // End namespace Foam

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

// Predefined dimensions (eg, dimless, dimMass, dimLength, dimTime, ...)
// and unit systems
#include "dimensionSets.H"

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

#endif

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