Project Ne10
An open, optimized software library for the ARM architecture.
NE10_sample_real_fft.c

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

/*
* Copyright 2011-16 ARM Limited and Contributors.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of ARM Limited nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY ARM LIMITED AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL ARM LIMITED AND CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdio.h>
#include <stdlib.h>
#include "NE10.h"
#define SAMPLES 16
{
ne10_float32_t src[SAMPLES] = {}; // A source array of input data
ne10_fft_cpx_float32_t dst[(SAMPLES / 2) + 1] = {}; // A destination array for the transformed data
ne10_fft_r2c_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 real-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.)
// Generate test input values
for (int i = 0; i < SAMPLES; i++)
{
src[i] = (ne10_float32_t)rand() / RAND_MAX * 50.0f;
}
// Perform the FFT
ne10_fft_r2c_1d_float32(dst, src, cfg);
// Display the results
for (int i = 0; i < SAMPLES; i++)
{
printf( "IN[%2d]: %10.4f\t", i, src[i]);
if (i <= SAMPLES / 2)
printf("OUT[%2d]: %10.4f + %10.4fi", i, dst[i].r, dst[i].i);
printf("\n");
}
// Free the allocated configuration structure
return 0;
}