kml_fft(f)_plan_dft_c2r_3d
Create a plan for the three-dimensional C2R transform of a single contiguous data sequence.
Interface Definition
C interface:
kml_fft_plan kml_fft_plan_dft_c2r_3d(int n0, int n1, int n2, kml_fft_complex *in, double *out, unsigned flags);
kml_fftf_plan kml_fftf_plan_dft_c2r_3d(int n0, int n1, int n2, kml_fftf_complex *in, float *out, unsigned flags);
Fortran interface:
RES = KML_FFT_PLAN_DFT_C2R_3D( N0, N1, IN, OUT, FLAGS);
RES = KML_FFTF_PLAN_DFT_C2R_3D( N0, N1, IN, OUT, FLAGS);
Return Value
The function returns a structure pointer of the kml_fft(f)_plan type. This object is used as a parameter in the kml_fft(f)_execute function to perform FFT on the current input and output. In addition, the object may also be added into the kml_fft(f)_execute_dft_c2r function as a parameter to perform FFT on the new input and output.
If this function returns a non-null pointer, the plan has been successfully executed. Otherwise, the plan failed to be executed.
Parameters
Parameter |
Data Type |
Description |
Input/Output |
|---|---|---|---|
n0 |
int |
Inputs the size of the first dimension in the FFT sequence. The constraint is n0 ≥ 1. |
Input |
n1 |
int |
Inputs the size of the second dimension in the FFT sequence. The constraint is n1 ≥ 1. |
Input |
n2 |
int |
Inputs the size of the third dimension in the FFT sequence. The constraint is n2 ≥ 1. |
Input |
in |
|
Inputs the data to be transformed. |
Input |
out |
|
Outputs the data generated using FFT. |
Output |
flags |
unsigned int |
A planning option, not in use. |
Input |
Dependencies
#include "kfft.h"
Examples
C interface:
int n0 = 2;
int n1 = 3;
int n2 = 4;
double init[18][2] = {{120, 0}, {8, 8}, {0, 0}, {0, 16}, {0, 16}, {-8, 8}, {-8, 0}, {-8, 8}, {-16, 0}, {0, -16}, {-40, 8}, {-8, -8},
{120, 0}, {8, 8}, {0, 0}, {0, 16}, {0, 16}, {-8, 8}};
kml_fft_complex *in;
in = (kml_fft_complex*)kml_fft_malloc(sizeof(kml_fft_complex) * n0 * n1 * (n2 / 2 + 1));
for (int i = 0; i < n0 * n1 * (n2 / 2 + 1); i++) {
in[i].r = init[i][0];
in[i].i = init[i][1];
}
double *out;
out = (double*)kml_fft_malloc(sizeof(double) * n0 * n1 * n2);
kml_fft_plan plan;
plan = kml_fft_plan_dft_c2r_3d(n0, n1, n2, in, out, KML_FFT_ESTIMATE);
kml_fft_execute_dft_c2r(plan, in, out);
kml_fft_free(in);
kml_fft_free(out);
/*
* out = {1.280000e+02, 1.440000e+02, 2.560000e+02, 4.000000e+02,
* 8.000000e+00, 4.428719e+01, 1.360000e+02, 6.771281e+01,
* 8.000000e+00, 9.971281e+01, 1.360000e+02, 1.228719e+01,
* 4.800000e+01, 0.000000e+00, -8.000000e+01, 0.000000e+00,
* 2.427180e+02, 1.541436e+02, 7.414359e+01, 1.541436e+02,
* 3.812820e+02, 1.818564e+02, 1.018564e+02, 1.818564e+02}
*/
Fortran interface:
INTEGER(C_INT) :: N0 = 2
INTEGER(C_INT) :: N1 = 3
INTEGER(C_INT) :: N2 = 4
REAL(C_DOUBLE), DIMENSION(18, 2) :: INIT
TYPE(KML_FFT_COMPLEX), POINTER :: IN
REAL(C_DOUBLE), POINTER :: OUT
TYPE(C_PTR) :: PIN, POUT
INTEGER(C_SIZE_T) :: CSIZE, RSIZE
CSIZE = N0 * N1 * (N2 / 2 + 1)
RSIZE = N0 * N1 * N2
PIN = KML_FFT_MALLOC(SIZEOF(16 * CSIZE))
POUT = KML_FFT_MALLOC(8 * RSIZE)
CALL C_F_POINTER(PIN, IN, SHAPE=[CSIZE])
CALL C_F_POINTER(POUT, OUT, SHAPE=[RSIZE])
DATA INIT/120, 8, 0, 0, 0, -8, -8, -8, -16, 0, -40, -8, 120, 8, 0, 0, 0, -8,0, 8, 0, 16, 16, 8, 0, 8, 0, 16, 8, -8, 0, 8, 0, 16, 16, 8/
INTEGER :: I
DO WHILE(I <= CSIZE)
IN(I)%R = INIT(I, 0)
IN(I)%I = INIT(I, 1)
END DO
TYPE(C_PTR) :: PLAN
PLAN = KML_FFT_PLAN_DFT_C2R_3D(N0, N1, N2, IN , OUT , KML_FFT_ESTIMATE);
CALL KML_FFT_EXECUTE_DFT_C2R(PLAN, IN, OUT);
CALL KML_FFT_DESTROY_PLAN(PLAN)
CALL KML_FFT_FREE(PIN)
CALL KML_FFT_FREE(POUT)
!
! OUT = /1.280000E+02, 1.440000E+02, 2.560000E+02, 4.000000E+02,
! 8.000000E+00, 4.428719E+01, 1.360000E+02, 6.771281E+01,
! 8.000000E+00, 9.971281E+01, 1.360000E+02, 1.228719E+01,
! 4.800000E+01, 0.000000E+00, -8.000000E+01, 0.000000E+00,
! 2.427180E+02, 1.541436E+02, 7.414359E+01, 1.541436E+02,
! 3.812820E+02, 1.818564E+02, 1.018564E+02, 1.818564E+02/
!