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fftn.h File Reference


Functions

void fft_free (void)
 Free-up allocated temporary storage after finished all the Fourier transforms.
int fftn (int ndim, const int dims[], double Re[], double Im[], int isign, double scaling)
 Compute fft with double precision.
int fftnf (int ndim, const int dims[], float Re[], float Im[], int isign, double scaling)

Function Documentation

void fft_free void   ) 
 

Free-up allocated temporary storage after finished all the Fourier transforms.

int fftn int  ndim,
const int  dims[],
double  Re[],
double  Im[],
int  isign,
double  scaling
 

Compute fft with double precision.

Parameters:
ndim Total number dimensions.
dims Vector of array sizes. If NDIM is zero then DIMS must be zero-terminated
Re Holds the real component of the data, and returns the resulting real Fourier coefficient. Multidimensional data *must* be allocated contiguously. There is no limit on the number of dimensions.
Im Holds the imaginary component of the data, and returns the resulting imaginary Fourier coefficient. Multidimensional data *must* be allocated contiguously. There is no limit on the number of dimensions.
isign Sign of the complex exponential (ie, forward or inverse FFT) the magnitude of ISIGN (normally 1) is used to determine the correct indexing increment (see below).
scaling Normalizing constant by which the final result is *divided* if scaling == -1, normalize by total dimension of the transform if scaling < -1, normalize by the square-root of the total dimension
example:
tri-variate transform with Re[n1][n2][n3], Im[n1][n2][n3]

int dims[3] = {n1,n2,n3} fftn (3, dims, Re, Im, 1, scaling);

int fftnf int  ndim,
const int  dims[],
float  Re[],
float  Im[],
int  isign,
double  scaling
 


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