---
title: kml_fft(f/h)_mpi_plan_dft_1d
description: "C interface:"
url: https://www.hikunpeng.com/document/detail/zh/kunpengaccel/math-lib/devg-kml/kunpengaccel_kml_0337.html
sourcePath: /source/zh/kunpengaccel/math-lib/devg-kml/kunpengaccel_kml_0337.html
indexId: c990613ae74ad2e85fd0cbc48c6174a2cce5840a93b3b98c8ac79dc0a9ae1cc568
---
# kml_fft(f/h)_mpi_plan_dft_1d

#### 接口定义

C interface:

kml_fft_plan kml_fft_mpi_plan_dft_1d(int n, kml_fft_complex *in, kml_fft_complex *out, MPI_comm comm, int sign, unsigned flags);

kml_fftf_plan kml_fftf_mpi_plan_dft_1d(int n, kml_fftf_complex *in, kml_fftf_complex *out, MPI_comm comm, int sign, unsigned flags);

kml_ffth_plan kml_ffth_mpi_plan_dft_1d(int n, kml_ffth_complex *in, kml_ffth_complex *out, MPI_comm comm, int sign, unsigned 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 |
| --- | --- | --- | --- |
| n | int | 输入FFT序列的大小，约束：n≥1。 | 输入 |
| in | 双精度：kml\_fft\_complex\* 单精度：kml\_fftf\_complex\* 半精度：kml\_ffth\_complex\* | 输入待变换的数据。 | 输入 |
| out | 双精度：kml\_fft\_complex\* 单精度：kml\_fftf\_complex\* 半精度：kml\_ffth\_complex\* | 输出快速傅里叶变换后的数据。 | 输出 |
| comm | MPI\_Comm | MPI通信器句柄。 | 输入 |
| 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-mpi.h"


#### 示例

C interface：

```
const ptrdiff_t N0 = 4;
kml_fft_plan plan;
ptrdiff_t alloc_local, local_ni, local_i_start, local_no, local_o_start;
MPI_Init(&argc, &argv);
MPI_Comm comm = MPI_COMM_WORLD;
kml_fft_mpi_init();
kml_fft_complex *in = NULL;
kml_fft_complex *out = NULL;
/* get local data size and allocate */
alloc_local = kml_fft_mpi_local_size_1d(N0, comm, KML_FFT_FORWARD, KML_FFT_MPI_TRANSPOSED_IN,
&local_ni, &local_i_start, &local_no, &local_o_start);
if (alloc_local == -1) {
printf("[%s][%d] allocate size fail!!!\n", __func__, __LINE__);
}
in = (kml_fft_complex *)kml_fft_malloc(sizeof(kml_fft_complex) * alloc_local);
if (in == NULL) {
printf("[%s][%d] malloc memory fail!!!\n", __func__, __LINE__);
}
out = (kml_fft_complex *)kml_fft_malloc(sizeof(kml_fft_complex) * alloc_local);
if (out == NULL) {
printf("[%s][%d] malloc memory fail!!!\n", __func__, __LINE__);
}
/* create plan for in-place forward DFT */
plan = kml_fft_mpi_plan_dft_1d(N0, in, out, comm,
KML_FFT_FORWARD, KML_FFT_MPI_TRANSPOSED_IN);
/* compute transforms, in-place, as many times as desired */
kml_fft_execute_dft(plan, int, out);
kml_fft_destroy_plan(plan);
MPI_Finalize();
return 0;
```