fftn(API)

DataManip/mrcImage/src/fftnは、FFT処理のためのAPI です。

API

extern void fft_free (void);

double precision routine

extern int fftn (int ndim, const int dims[], double Re[], double Im[],
		 int isign, double scaling);

float precision routine

extern int fftnf (int ndim, const int dims[], float Re[], float Im[],
		  int isign, double scaling);

変数の意味

このAPIの変数は以下のような用途で使用されています。

Re[]:	real value array
Im[]:	imaginary value array
nTotal:	total number of complex values
nPass:	number of elements involved in this pass of transform
nSpan:	nspan/nPass = number of bytes to increment pointer
		in Re[] and Im[]
isign:	exponent: +1 = forward  -1 = reverse
 scaling:	normalizing constant by which the final result is *divided*
	scaling == -1, normalize by total dimension of the transform
	scaling <  -1, normalize by the square-root of the total dimension