kml_fft(f)_plan_dft
建立单个连续数据序列n维C2C变换的plan。
接口定义
C interface：
kml_fft_plan kml_fft_plan_dft(int rank, const int *n, kml_fft_complex *in, kml_fft_complex *out, int sign, unsigned flags);
kml_fftf_plan kml_fftf_plan_dft(int rank, const int *n, kml_fftf_complex *in, kml_fftf_complex *out, int sign, unsigned flags);
Fortran interface：
RES = KML_FFT_PLAN_DFT(RANK, N, IN, OUT, SIGN, FLAGS);
RES = KML_FFTF_PLAN_DFT(RANK, N, IN, OUT, SIGN, FLAGS);
返回值
函数返回一个kml_fft(f)_plan类型的结构体指针。将该对象作为参数传入kml_fft(f)_execute函数中使用，将对当前提供的输入in和输出out执行FFT变换；另外，也可以通过将该对象作为参数传入kml_fft(f)_execute_dft函数中以对新的输入in和输出out执行FFT变换。
如果函数返回非空指针，则表示plan执行成功，否则表示执行失败。
参数
参数名 |
数据类型 |
描述 |
输入/输出 |
|---|---|---|---|
rank |
int |
FFT变换的维度是rank，约束：1≤rank≤3。 |
输入 |
n |
const int* |
n是维度为rank的数组，包含FFT序列每一维度的大小，约束：n[i]≥1, for i in 0 to rank - 1。 |
输入 |
in |
|
输入待变换的数据。 |
输入 |
out |
|
输出快速傅里叶变换后的数据。 |
输出 |
sign |
int |
描述正向变换或反向变换。
|
输入 |
flags |
unsigned int |
planning选项，未使用。 |
输入 |
依赖
C: "kfft.h"
Fortran: "kfft.f03"
示例
C interface：
int rank = 2;
int *n;
n = (int*)kml_fft_malloc(sizeof(int) * rank);
n[0] = 2;
n[1] = 3;
double init[6][2] = {{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) * n[0] * n[1]);
for (int i = 0; i < n[0] * n[1]; i++) {
in[i].r = init[i][0];
in[i].i = init[i][1];
}
kml_fft_complex *out;
out = (kml_fft_complex*)kml_fft_malloc(sizeof(kml_fft_complex) * n[0] * n[1]);
kml_fft_plan plan;
plan = kml_fft_plan_dft(rank, n, in, out, KML_FFT_FORWARD, KML_FFT_ESTIMATE);
kml_fft_execute_dft(plan, in, out);
kml_fft_destroy_plan(plan);
kml_fft_free(n);
kml_fft_free(in);
kml_fft_free(out);
/*
* out = {{1.200000e+02, 4.800000e+01}, {1.338564e+02, -1.385641e+01},
* {1.061436e+02, 1.385641e+01}, {1.360000e+02, -3.200000e+01},
* {1.120000e+02, -8.000000e+00}, {1.120000e+02, -8.000000e+00}}
*/
Fortran interface：
INTEGER(C_INT) :: RANK = 2
INTEGER(C_INT), DIMENSION(*) :: N
N = KML_FFT_MALLOC(4 * RANK)
N(0) = 2
N(1) = 3
REAL(C_DOUBLE) :: INIT(6, 2)
TYPE(C_PTR) :: PLAN
TYPE(KML_FFT_COMPLEX), POINTER :: IN, OUT
TYPE(C_PTR) :: PIN, POUT
TYPE(C_SIZE_T) :: SIZE
SIZE = 16 * N(0) * N(1)
IN = KML_FFT_MALLOC(SIZE)
OUT = KML_FFT_MALLOC(SIZE)
CALL C_F_POINTER(PIN, IN, SHAPE=[N(1) * N(2)])
CALL C_F_POINTER(POUT, OUT, SHAPE=[N(1) * N(2)])
DATA INIT/120, 8, 0, 0, 0, -8, 0, 8, 0, 16, 16, 8/
INTEGER I
DO WHILE(I <= N(0) * N(1))
IN(I)%R = INIT(I, 0)
IN(I)%I = INIT(I, 1)
END DO
PLAN = KML_FFT_PLAN_DFT(RANK, 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(N)
CALL KML_FFT_FREE(PIN)
CALL KML_FFT_FREE(POUT)
!
! OUT = /120.00000000000000D0, 133.85640646055103D0,
! 106.14359353944897D0, 136.00000000000000D0,
! 112.00000000000000D0, 112.00000000000000D0,
! 48.000000000000000D0, -13.856406460551021D0,
! 13.856406460551021D0, -32.000000000000000D0,
! -8.0000000000000000D0, -8.0000000000000000D0/
!