---
title: kml_fft(f)_malloc
description: "kml_fft(f)_malloc用于分配所需的内存空间。所申请的内存空间只能通过调用kml_fft(f)_free函数释放。"
url: https://www.hikunpeng.com/document/detail/zh/kunpengboostkithistory/2200/accel/kunpengaccel_kml_16_0175.html
sourcePath: /source/zh/kunpengboostkithistory/2200/accel/kunpengaccel_kml_16_0175.html
indexId: d460f6fda24272ca1f1b8dde4309348cbe27f0638999f09e529e804f259f141974
---
# kml_fft(f)_malloc

kml_fft(f)_malloc用于分配所需的内存空间。所申请的内存空间只能通过调用kml_fft(f)_free函数释放。

#### 接口定义

C interface：

void* kml_fft_malloc(size_t n);

void* kml_fftf_malloc(size_t n);

Fortran interface：

RES = KML_FFT_MALLOC(N);

RES = KML_FFTF_MALLOC(N);


#### 返回值

函数返回一个void*类型的指针，指向已分配的内存块


#### 参数

| 参数名 | 数据类型 | 描述 | 输入/输出 |
| --- | --- | --- | --- |
| n | size\_t | 需要申请的内存大小（以bytes为单位）。 | 输入 |


#### 依赖

C: "kfft.h"

Fortran: "kfft.f03"


#### 示例

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(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/
!
```