---
title: kml_fft(f)_plan_dft
description: "建立单个连续数据序列n维C2C变换的plan。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/240RC1/accel/kunpengaccel_kml_16_0126.html
sourcePath: /source/zh/kunpengboostkithistory/240RC1/accel/kunpengaccel_kml_16_0126.html
indexId: 03de0f2bb03236c2cad24e74af4d301536c64c478f87f93f51fa1fbacf066c8676
---
# 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 | 双精度：kml\_fft\_complex\* 单精度：kml\_fftf\_complex\* | 输入待变换的数据。 | 输入 |
| out | 双精度：kml\_fft\_complex\* 单精度：kml\_fftf\_complex\* | 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。 \-1(KML\_FFT\_FORWARD)：forward +1(KML\_FFT\_BACKWARD)：backward | 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/
!
```