fft.H

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License
    This file is part of OpenFOAM.

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    the Free Software Foundation, either version 3 of the License, or
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Class
    Foam::fft

Description
    Fast fourier transform derived from the Numerical
    Recipes in C routine.

    The complex transform field is returned in the field supplied.  The
    direction of transform is supplied as an argument (1 = forward, -1 =
    reverse).  The dimensionality and organisation of the array of values
    in space is supplied in the nn indexing array.

SourceFiles
    fft.C

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

#ifndef fft_H
#define fft_H

#include "complexFields.H"
#include "labelList.H"

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

namespace Foam
{

class fft
{

public:

    enum transformDirection
    {
        FORWARD_TRANSFORM = 1,
        REVERSE_TRANSFORM = -1
    };


    static void transform
    (
        complexField& field,
        const labelList& nn,
        transformDirection fftDirection
    );


    static tmp<complexField> forwardTransform
    (
        const tmp<complexField>& field,
        const labelList& nn
    );


    static tmp<complexField> reverseTransform
    (
        const tmp<complexField>& field,
        const labelList& nn
    );


    static tmp<complexVectorField> forwardTransform
    (
        const tmp<complexVectorField>& field,
        const labelList& nn
    );


    static tmp<complexVectorField> reverseTransform
    (
        const tmp<complexVectorField>& field,
        const labelList& nn
    );
};


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

} // End namespace Foam

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

#endif

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