NE10_sample_complex_fft.c

An example of using the complex-to-complex FFT functions.

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#include <stdio.h>
#include <stdlib.h>

#include "NE10.h"

#define SAMPLES 16

int complex_fft_sample_main(void)
{
    ne10_fft_cpx_float32_t src[SAMPLES]; // A source array of input data
    ne10_fft_cpx_float32_t dst[SAMPLES]; // A destination array for the transformed data
    ne10_fft_cfg_float32_t cfg;          // An FFT "configuration structure"

    // Initialise Ne10, using hardware auto-detection to set library function pointers
    if (ne10_init() != NE10_OK)
    {
        fprintf(stderr, "Failed to initialise Ne10.\n");
        return 1;
    }

    // Prepare the complex-to-complex single precision floating point FFT configuration
    // structure for inputs of length `SAMPLES`. (You need only generate this once for a
    // particular input size.)
    cfg = ne10_fft_alloc_c2c_float32(SAMPLES);

    // Generate test input values (with both real and imaginary components)
    for (int i = 0; i < SAMPLES; i++)
    {
        src[i].r = (ne10_float32_t)rand() / RAND_MAX * 50.0f;
        src[i].i = (ne10_float32_t)rand() / RAND_MAX * 50.0f;
    }

    // Perform the FFT (for an IFFT, the last parameter should be `1`)
    ne10_fft_c2c_1d_float32(dst, src, cfg, 0);

    // Display the results
    for (int i = 0; i < SAMPLES; i++)
    {
        printf( "IN[%2d]: %10.4f + %10.4fi\t", i, src[i].r, src[i].i);
        printf("OUT[%2d]: %10.4f + %10.4fi\n", i, dst[i].r, dst[i].i);
    }

    // Free the allocated configuration structure
    ne10_fft_destroy_c2c_float32(cfg);

    return 0;
}