GFFTDianelsonLanczos.hh

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//======================================================================
/*! \file GFFTDianelsonLanczos.hh
 *
 *  Include file for the Fast Fourier Transform (FFT) functions using the
 *  Danielson-Lanczos algorithm (see \ref FFT_Dianelson_Lanczos).
 */
//======================================================================

#ifndef G_FFT_DIANELSON_LANCZOS_HH
#define G_FFT_DIANELSON_LANCZOS_HH

//======================================================================

#include <math.h>
#include "GGlobal.hh"
#include "GBaseFunctions.hh"
#include "GStringFunctions.hh"
#include "GString.hh"

//!  Pi value
#define FFT_PI          M_PIl
//!  2*Pi value
#define FFT_2PI         (2*M_PIl)

//! Conversion factor from standard deviation to FWHM
#define FFT_SIGMA_TO_FWHM   2.354820045030949327014013761072419583797L
//! Conversion factor from FWHM to standard deviation
#define FFT_FWHM_TO_SIGMA   0.424660900144009534340483469350147061050L

//! Swap 2 double values
#define SWAP_DOUBLE(a,b)   {double _tmp=(a);(a)=(b);(b)=_tmp;}


// Error codes for FFT functions

//! Bad array dimension (typically not a power of 2)
#define GFFT_DIM_ERROR       1
//! Invalid transform mode
#define GFFT_MODE_ERROR      2
//! Memory allocation error
#define GFFT_ALLOC_ERROR     3

//======================================================================
//  FFT BASE FUNCTIONS

extern  bool  GFFTCheckDim      ( u_int n );
extern  u_int GFFTGetPower2Dim  ( u_int n );

extern  int   GFFTBaseComplex ( double data[], u_int n, bool inv = false );
extern  int   GFFTComplex     ( double f_in[],  double f_out[], u_int n, bool inv = false);
extern  int   GFFTReal2       ( double f_in1[], double f_in2[], double f_out1[], double f_out2[], u_int n, bool inv = false);

extern  int   GFFTBaseReal    ( double data[], u_int n, bool inv = false );
extern  int   GFFTReal        ( double f_in[], double f_out[], u_int n, bool inv = false);

//======================================================================
#endif