kml_fft(f)_plan_dft_1d

Create a plan for the one-dimensional C2C transform of a single contiguous data sequence.

Interface Definition

C interface:

kml_fft_plan kml_fft_plan_dft_1d(int n, kml_fft_complex *in, kml_fft_complex *out, int sign, unsigned flags);

kml_fftf_plan kml_fftf_plan_dft_1d(int n, kml_fftf_complex *in, kml_fftf_complex *out, int sign, unsigned flags);

Fortran interface:

RES = KML_FFT_PLAN_DFT_1D(N, IN, OUT, SIGN, FLAGS);

RES = KML_FFTF_PLAN_DFT_1D(N, IN, OUT, SIGN, 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 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
n	int	Inputs the FFT sequence size. The constraint is n ≥ 1.	Input
in	Double precision: kml_fft_complex* Single precision: kml_fftf_complex*	Inputs the data to be transformed.	Input
out	Double precision: kml_fft_complex* Single precision: kml_fftf_complex*	Outputs the data generated using FFT.	Output
sign	int	Specifies forward or backward transform. -1(KML_FFT_FORWARD): forward +1(KML_FFT_BACKWARD): backward	Input
flags	unsigned int	A planning option, not in use.	Input

Dependencies

C: "kfft.h"

Fortran: "kfft.f03"

Examples

C interface:

    int N = 16; 
    kml_fft_complex *in; 
    kml_fft_complex *out; 
    kml_fft_plan plan; 
    in = (kml_fft_complex*)kml_fft_malloc(sizeof(kml_fft_complex) * N); 
    out = (kml_fft_complex*)kml_fft_malloc(sizeof(kml_fft_complex) * N); 
    for (int i = 0; i < N; i++){ 
        in[i].r = (double)i; 
        in[i].i = (double)i; 
    } 
    plan = kml_fft_plan_dft_1d(N, in , out, KML_FFT_FORWARD, KML_FFT_ESTIMATE); 
    kml_fft_execute_dft(plan, in, out); 
 
    kml_fft_destroy_plan(plan); 
    kml_fft_free(in); 
    kml_fft_free(out); 
 
    /* 
     * out = {{1.200000e+02, 1.200000e+02}, {-4.821872e+01, 3.221872e+01}, 
     *        {-2.731371e+01, 1.131371e+01}, {-1.997285e+01, 3.972846e+00}, 
     *        {-1.600000e+01, 0.000000e+00}, {-1.334543e+01, -2.654571e+00}, 
     *        {-1.131371e+01, -4.686292e+00}, {-9.591299e+00, -6.408701e+00}, 
     *        {-8.000000e+00, -8.000000e+00}, {-6.408701e+00, -9.591299e+00}, 
     *        {-4.686292e+00, -1.131371e+01}, {-2.654571e+00, -1.334543e+01}, 
     *        {0.000000e+00, -1.600000e+01}, {3.972846e+00, -1.997285e+01}, 
     *        {1.131371e+01, -2.731371e+01}, {3.221872e+01, -4.821872e+01}} 
     */

Fortran interface:

    INTEGER(C_INT) :: N = 16 
    TYPE(KML_FFT_COMPLEX), POINTER :: IN, OUT 
    TYPE(C_PTR) :: PIN, POUT 
    TYPE(C_PTR) :: PLAN 
    INTEGER(C_SIZE_T) :: SIZE 
    SIZE = 16 * N 
    PIN = KML_FFT_MALLOC(SIZE) 
    POUT = KML_FFT_MALLOC(SIZE) 
    CALL C_F_POINTER(PIN, IN, SHAPE=[N]) 
    CALL C_F_POINTER(POUT, OUT, SHAPE=[N]) 
    INTEGER :: I 
    DO WHILE(I <= N) 
        IN%R = I 
        IN%I = I 
    END DO 
    PLAN = KML_FFT_PLAN_DFT_1D(N, IN , OUT, KML_FFT_FORWARD, KML_FFT_ESTIMATE) 
    CALL KML_FFT_EXECUTE_DFT(PLAN, IN, OUT) 
 
    CALL KML_FFT_DESTROY_PLAN(PLAN) 
    CALL KML_FFT_FREE(PIN) 
    CALL KML_FFT_FREE(POUT) 
 
    ! 
    ! OUT = \1.200000E+02, 1.200000E+0, -4.821872E+01, 3.221872E+01, 
    !        -2.731371E+01, 1.131371E+01, -1.997285E+01, 3.972846E+00, 
    !        -1.600000E+01, 0.000000E+00, -1.334543E+01, -2.654571E+00, 
    !        -1.131371E+01, -4.686292E+00, -9.591299E+00, -6.408701E+00, 
    !        -8.000000E+00, -8.000000E+00, -6.408701E+00, -9.591299E+00, 
    !        -4.686292E+00, -1.131371E+01, -2.654571E+00, -1.334543E+01, 
    !        0.000000E+00, -1.600000E+01, 3.972846E+00, -1.997285E+01, 
    !        1.131371E+01, -2.731371E+01, 3.221872E+01, -4.821872E+01/ 
    !

Parent topic: C2C Transforms