kml_fft(f)_plan_dft_r2c_3d
Create a plan for the three-dimensional R2C transform of a single contiguous data sequence.
Interface Definition
C interface:
kml_fft_plan kml_fft_plan_dft_r2c_3d(int n0, int n1, int n2, double *in, kml_fft_complex *out, unsigned flags);
kml_fftf_plan kml_fftf_plan_dft_r2c_3d(int n0, int n1, int n2, float *in, kml_fftf_complex *out, unsigned flags);
Fortran interface:
RES = kml_fft_plan_dft_r2c_2d(N0, N1, N2, IN, OUT, FLAGS);
RES = kml_fftf_plan_dft_r2c_2d(N0, N1, N2, 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_r2c 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
C: "kfft.h"
Fortran: "kfft.f03"
Examples
C interface:
int n0 = 2;
int n1 = 3;
int n2 = 2;
double init[12] = {120, 8, 0, 0, 0, -8, -8, -8, -16, 0, -40, -8};
double *in;
in = (double*)kml_fft_malloc(sizeof(double) * n0 * n1 * n2);
for (int i = 0; i < n0 * n1 * n2; i++) {
in[i] = init[i];
}
kml_fft_complex *out;
out = (kml_fft_complex*)kml_fft_malloc(sizeof(kml_fft_complex) * n0 * n1 * (n2 / 2 + 1));
kml_fft_plan plan;
plan = kml_fft_plan_dft_r2c_3d(n0, n1, n2, in, out, KML_FFT_ESTIMATE);
kml_fft_execute_dft_r2c(plan, in, out);
kml_fft_destroy_plan(plan);
kml_fft_free(in);
kml_fft_free(out);
/*
* out = {{4.000000e+01, 0.000000e+00}, {7.200000e+01, 0.000000e+00},
* {1.480000e+02, -3.464102e+01}, {1.320000e+02, -6.928203e+00},
* {1.480000e+02, 3.464102e+01}, {1.320000e+02, 6.928203e+00},
* {2.000000e+02, 0.000000e+00}, {1.680000e+02, 0.000000e+00},
* {1.160000e+02, 2.078461e+01}, {8.400000e+01, 2.078461e+01},
* {1.160000e+02, -2.078461e+01}, {8.400000e+01, -2.078461e+01}}
*/
Fortran interface:
INTEGER(C_INT) :: N0 = 2
INTEGER(C_INT) :: N1 = 3
INTEGER(C_INT) :: N2 = 2
REAL(C_DOUBLE) :: INIT(12)
REAL(C_DOUBLE), POINTER :: IN
TYPE(KML_FFT_COMPLEX), POINTER :: OUT
TYPE(C_PTR) :: PIN, POUT
INTEGER(C_SIZE_T) :: RSIZE, CSIZE
RSIZE = N0 * N1 * N2
CSIZE = N0 * N1 * (N2 / 2 + 1)
PIN = KML_FFT_MALLOC(8 * RSIZE)
POUT = KML_FFT_MALLOC(16 * CSIZE)
CALL C_F_POINTER(PIN, IN, SHAPE=[RSIZE])
CALL C_F_POINTER(POUT, OUT, SHAPE=[CSIZE])
DATA INIT/120, 8, 0, 0, 0, -8, -8, -8, -16, 0, -40, -8/
INTEGER :: I
DO WHILE(I <= RSIZE)
IN(I) = INIT(I)
END DO
TYPE(C_PTR) :: PLAN
PLAN = KML_FFT_PLAN_DFT_R2C_3D(N0, N1, N2, IN, OUT, KML_FFT_ESTIMATE)
CALL KML_FFT_EXECUTE_DFT_R2C(PLAN, IN, OUT)
CALL KML_FFT_DESTROY_PLAN(PLAN)
CALL KML_FFT_FREE(PIN)
CALL KML_FFT_FREE(POUT)
!
! OUT = /4.000000E+01, 0.000000E+00, 7.200000E+01, 0.000000E+00,
! 1.480000E+02, -3.464102E+01, 1.320000E+02, -6.928203E+00,
! 1.480000E+02, 3.464102E+01, 1.320000E+02, 6.928203E+00,
! 2.000000E+02, 0.000000E+00, 1.680000E+02, 0.000000E+00,
! 1.160000E+02, 2.078461E+01, 8.400000E+01, 2.078461E+01,
! 1.160000E+02, -2.078461E+01, 8.400000E+01, -2.078461E+01/
!