File content as of revision 1:f070e455cea0:

//--------------------------------------------------------------
// Demo program of FftReal class
// Copyright (c) 2014 MIKAMI, Naoki,  2014/12/19
//--------------------------------------------------------------

#include "dftComplex.hpp"
#include "fftReal.hpp"

#include "mbed.h"

using namespace Mikami;

int main()
{
    const int N = 256;//16;       // number of date for FFT

    float x1[N], x2[N];
    Complex y1[N], y2[N/2+1];

    // Generate random data
    srand(1234);
    for (int n=0; n<N; n++)
        x1[n] = 2.0f*rand()/(float)RAND_MAX - 1.0f;
    printf("\r\n#### Original data for DFT ####\r\n");
    for (int n=0; n<N; n++)
        printf("f[%2d]: %8.4f\r\n", n, x1[n]);

    // DFT, for comarison
    DftComplex(x1, y1, N);
    printf("\r\n#### Result of direct DFT ####\r\n");
    printf("          real    imaginary\r\n");
    for (int n=0; n<N; n++)
        printf("F[%2d]: %8.4f, %8.4f\r\n", n, y1[n].real(), y1[n].imag());

    Timer tm;   // for measurement of execution time

    // FFT
    FftReal fft(N);
    tm.reset();
    tm.start();
    fft.Execute(x1, y2);
    tm.stop();
    printf("\r\nExecution time (FFT): %d [us]\r\n", tm.read_us());
    printf("\r\n#### Result of DFT using FFT ####\r\n");
    for (int n=0; n<=N/2; n++)
        printf("F[%2d]: %8.4f, %8.4f\r\n", n, y2[n].real(), y2[n].imag());
    
    // IFFT
    tm.reset();
    tm.start();
    fft.ExecuteIfft(y2, x2);
    tm.stop();
    printf("\r\nExecution time (IFFT): %d [us]\r\n", tm.read_us());
    printf("\r\n#### Result of IFFT ####\r\n");
    printf("        original  IFFT of FFT\r\n");
    for (int n=0; n<N; n++)
        printf("f[%2d]: %8.4f, %8.4f\r\n", n, x1[n], x2[n]);
}