• 中文
  • 3.8.1

    • Inverse Fast Fourier Transform

    快速傅里叶逆变换（Inverse Fast Fourier Transform，以下简称IFFT）是离散傅里叶逆变换（Inverse Discrete Fourier Transform，以下简称IDFT）的快速算法， 是时域一频域变换分析中最基本的方法之一。该算法可以实现数据从频域到时域之间的转换。

    算子效果

    时域输入数据参数频域输出数据
    imagepSize = HB_FFT_POINT_SIZE_16image

    原理

    请参考FFT章节原理。

    API接口

    int32_t hbIFFT1D(hbUCPTaskHandle_t *taskHandle, hbHPLImaginaryData *dst,
                 hbHPLImaginaryData const *src, hbIFFTParam const *param);

    详细接口信息请查看 hbIFFT1D。

    使用方法

    // Include the header
#include "hobot/hb_ucp.h"
#include "hobot/hpl/hb_hpl.h"
#include "hobot/hpl/hb_ifft.h"

// init, allocate memory for data
src_length = 1024 * 1024 * 5;
hbUCPMallocCached(&src_re_mem, src_length, 0);
hbUCPMallocCached(&src_im_mem, src_length, 0);
hbHPLImaginaryData src;
src.realDataVirAddr = src_re_mem.virAddr;
src.realDataPhyAddr = src_re_mem.phyAddr;
src.imDataVirAddr = src_im_mem.virAddr;
src.imDataPhyAddr = src_im_mem.phyAddr;
src.numDimensionSize = 1;
src.dataType = HB_HPL_DATA_TYPE_I16;
src.imFormat = HB_IM_FORMAT_SEPARATE;
src.dimensionSize[0] = 16 * 11;

hbUCPMallocCached(&dst_re_mem, src_length, 0);
hbUCPMallocCached(&dst_im_mem, src_length, 0);
hbHPLImaginaryData dst;
dst.realDataVirAddr = dst_re_mem.virAddr;
dst.realDataPhyAddr = dst_re_mem.phyAddr;
dst.imDataVirAddr = dst_im_mem.virAddr;
dst.imDataPhyAddr = dst_im_mem.phyAddr;
dst.numDimensionSize = 1;
dst.dataType = HB_HPL_DATA_TYPE_I16;
dst.imFormat = HB_IM_FORMAT_SEPARATE;
dst.dimensionSize[0] = 16 * 11;

// init param
hbIFFTParam param;
param.pSize = HB_FFT_POINT_SIZE_16;

// init task handle and schedule param
hbUCPTaskHandle_t task_handle{nullptr};
hbUCPSchedParam sched_param;
HB_UCP_INITIALIZE_SCHED_PARAM(&sched_param);
sched_param.backend = HB_UCP_DSP_CORE_0;

// create task
hbIFFT1D(&task_handle, &dst, &src, &param);

// submit task
hbUCPSubmitTask(task_handle, &sched_param);

// wait for task done 
hbUCPWaitTaskDone(task_handle, 0);

// release task handle
hbUCPReleaseTask(task_handle);

// release memory
hbUCPFree(&src_re_mem);
hbUCPFree(&src_im_mem);
hbUCPFree(&dst_re_mem);
hbUCPFree(&dst_im_mem);