UT/UT_FFT.h

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/*
 * PROPRIETARY INFORMATION.  This software is proprietary to
 * Side Effects Software Inc., and is not to be reproduced,
 * transmitted, or disclosed in any way without written permission.
 *
 * Produced by:
 *      Mark Alexander
 *      Side Effects Software Inc
 *      477 Richmond Street West
 *      Toronto, Ontario
 *      Canada   M5V 3E7
 *      416-504-9876
 *
 * NAME:        UT_FFT.h
 *
 * COMMENTS:
 *
 *      Performs a fast discrete fourier transform (or an inverse) on
 *      array data.
 *      FORWARD: Takes real data and produces complex data.
 *      INVERSE: Takes complex data and produces real data.
 */

#ifndef __UT_FFT__
#define __UT_FFT__

#include "UT_API.h"
#include <SYS/SYS_Types.h>

class UT_API UT_FFT
{
public:
    explicit UT_FFT(long npnts);
    ~UT_FFT();

    void toFrequency(float *source,float *destr,float *desti,long npnts);
    void toFrequency(float *sourcer, float *sourcei,float *destr,float *desti,long npnts);
    void toTime(float *sourcer,float *sourcei,float *dest,long npnts);

    void toTime(float *sourcer,float *sourcei,float *destr,float *desti,long npnts);

    // two dimensional FFT'ing
    static void toFrequency2D(float *sourcer, float *sourcei, float *destr,float *desti,long size);
    static void toTime2D(float *sourcer, float *sourcei, float *destr,float *desti,long size);

private:

    int for_fft(float *yre, float *yim,float *zre,float *zim,int npts);
    int inv_fft(float *yre, float *yim,float *zre,float *zim,int npts);

    void dofft(int agamma);
    void fftcopy(float *pr_from, float *pi_from,float *p_to,
                 int npts,int is_plus);
    
    void ifftcopy(float *p_from, float *pr_to,float *pi_to,
                  int agamma,fpreal factr,fpreal facti);
    void fftfill(float *p_co,int part,int all);
    
    void make_w(int neww);
    void butterfly(int fly,int agamma);

    static void init_bitsw();
    static int slow_bitsw(int k,int n);
    static int bitswitch(int k,int n);
        
    float *x_co;
    float *w_co;
    
    static unsigned char tbl[256];
    int gamma,fft_size;

};
    
#endif

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