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「DCexchange」(2009/01/21 (水) 20:48:47) の最新版変更点

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//cpp
/**
* @brief origin shift (top-left <-> center)
* @author maeda
* @date 2008/09/10
*/
#include "DCexchange.h"

/**
* in-place DC exchange for 2dimensional data (top-left <-> center)
* this function works both odd/even size data
* @param data fft data
* @param cols column size of the data ( sometimes the size of x )
* @param rows row size of the data ( sometimes the size of y )
* @return true if succeed
*/
int maDCexchange2D( fftw_complex *data, int cols, int rows )
{
	int i,j;
	int p1,p2;    // point position
	int c2,r2;    // temporary for cols/2,rows/2
	double re,im; // temporary

	if( data==NULL )       return false;
	if( rows<0 || cols<0 ) return false;

	c2 = cols/2;
	r2 = rows/2;

	for( j=0; j<r2; j++ ){
		for( i=0; i<cols; i++ ){
			// exchange p1( i, j ) <-> p2( (cols/2+i)%cols, rows/2+j )
			p1 = j*cols + i;
			p2 = (r2+j)*cols + (r2+i)%cols;
			re = data[p1][0];
			im = data[p1][1];
			data[p1][0] = data[p2][0];
			data[p1][1] = data[p2][1];
			data[p2][0] = re;
			data[p2][1] = im;
		}
	}

	return true;
}

//cpp
/**
* @brief origin shift (top-left <-> center)
* @author maeda
* @date 2008/09/10
*/
#include "DCexchange.h"

/**
* in-place DC exchange for 2dimensional data (top-left <-> center)
* this function works both odd/even size data
* @param data fft data
* @param cols column size of the data ( sometimes the size of x )
* @param rows row size of the data ( sometimes the size of y )
* @return true if succeed
*/
int maDCexchange2D( fftw_complex *data, int cols, int rows )
{
	int i,j;
	int p1,p2;    // point position
	int c2,r2;    // temporary for cols/2,rows/2
	double re,im; // temporary

	if( data==NULL )       return false;
	if( rows<0 || cols<0 ) return false;

	c2 = cols/2;
	r2 = rows/2;

	for( j=0; j<r2; j++ ){
		for( i=0; i<cols; i++ ){
			// exchange p1( i, j ) <-> p2( (cols/2+i)%cols, rows/2+j )
			p1 = j*cols + i;
			p2 = (r2+j)*cols + (c2+i)%cols;
			re = data[p1][0];
			im = data[p1][1];
			data[p1][0] = data[p2][0];
			data[p1][1] = data[p2][1];
			data[p2][0] = re;
			data[p2][1] = im;
		}
	}

	return true;
}