/usr/share/doc/mffm-fftw-dev/examples/realFFTExample.cc is in mffm-fftw-dev 1.7-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | /* Copyright 2001,2002 Matt Flax <flatmax@ieee.org>
This file is part of the MFFM FFTw Wrapper library.
MFFM MFFM FFTw Wrapper library is free software; you can
redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
MFFM FFTw Wrapper library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You have received a copy of the GNU General Public License
along with the MFFM FFTw Wrapper library
*/
#include <fstream>
#include <iostream>
using namespace std;
#include <mffm/realFFT.H>
#include <stdlib.h>
#define INPUTFILE "sine.1000Hz.dat"
#define OUTPUTFILE "powerSpectrum.txt"
#define OUTPUTFILE1 "in.txt"
#define OUTPUTFILE2 "out.txt"
int main (void){
ifstream input(INPUTFILE);
ofstream output(OUTPUTFILE);
ofstream output1(OUTPUTFILE1);
ofstream output2(OUTPUTFILE2);
int count=0;
double var;
// Get the file size and check file exists ....
if (!input){
cout <<"input not opened !"<<endl;
exit(-1);
}
while (input >> var)
count++;
//input.close();
cout<<count<<" variables in file "<<INPUTFILE<<endl;
//input.open(INPUTFILE);
input.clear();
input.seekg(0);
realFFTData fftData(count);
realFFT rfft(&fftData);
// read data into data and rdata :
for (int i=0; i<count; i++)
input >> fftData.in[i];
input.close();
// forward transform :
rfft.fwdTransform();
// Find the power spectrum ...
fftData.compPowerSpec();
for (int i=0; i<count; i++)
fftData.in[i]=0.0;
// inverse transform to check what happens (have to rescale too):
rfft.invTransform();
// output to file :
for (int i=0; i<(count+1)/2; i++){
output << fftData.power_spectrum[i]<<'\n';
}
// cout <<(count+1)/2<<endl;
output.close();
for (int i=0; i<count; i++){
output1 << fftData.in[i]/count<<'\n';
output2 << fftData.out[i]<<'\n';
}
output1.close();
output2.close();
return 0;
}
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