fft.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
    (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::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
 
// ************************************************************************* //