GRASS GIS 7 Programmer's Manual
7.9.dev(2021)-e5379bbd7
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Fast Fourier Transformation of Two Dimensional Satellite Data functions. More...
#include <grass/config.h>
#include <fftw3.h>
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <grass/gmath.h>
#include <grass/gis.h>
Go to the source code of this file.
Macros | |
#define | c_re(c) ((c)[0]) |
#define | c_im(c) ((c)[1]) |
Functions | |
int | fft2 (int i_sign, double(*data)[2], int NN, int dimc, int dimr) |
Fast Fourier Transform for two-dimensional array. More... | |
int | fft (int i_sign, double *DATA[2], int NN, int dimc, int dimr) |
Fast Fourier Transform for two-dimensional array. More... | |
Fast Fourier Transformation of Two Dimensional Satellite Data functions.
This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
Definition in file fft.c.
int fft | ( | int | i_sign, |
double * | DATA[2], | ||
int | NN, | ||
int | dimc, | ||
int | dimr | ||
) |
Fast Fourier Transform for two-dimensional array.
Fast Fourier Transform for two-dimensional array.
<bNote: If passing real data to fft() forward transform (especially when using fft() in a loop), explicitly (re-)initialize the imaginary part to zero (DATA[1][i] = 0.0). Returns 0.
[in] | i_sign | Direction of transform -1 is normal, +1 is inverse |
[in,out] | DATA | Pointer to complex linear array in row major order containing data and result |
[in] | NN | Value of DATA dimension (dimc * dimr) |
[in] | dimc | Value of image column dimension (max power of 2) |
[in] | dimr | Value of image row dimension (max power of 2) |
Definition at line 127 of file fft.c.
Referenced by del2g().
int fft2 | ( | int | i_sign, |
double(*) | data[2], | ||
int | NN, | ||
int | dimc, | ||
int | dimr | ||
) |
Fast Fourier Transform for two-dimensional array.
Fast Fourier Transform for two-dimensional array.
<bNote: If passing real data to fft() forward transform (especially when using fft() in a loop), explicitly (re-)initialize the imaginary part to zero (DATA[1][i] = 0.0). Returns 0.
[in] | i_sign | Direction of transform -1 is normal, +1 is inverse |
[in,out] | data | Pointer to complex linear array in row major order containing data and result |
[in] | NN | Value of DATA dimension (dimc * dimr) |
[in] | dimc | Value of image column dimension (max power of 2) |
[in] | dimr | Value of image row dimension (max power of 2) |