realFFTExample.cc

This is an example of how to use the class. It transforms a sine tone stored in the .dat file and saves the in, out, and power_spectrum results of using the class

/* 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;
}
realFFTData
class realFFTData controls and manipulates fft data
Definition realFFTData.H:32
realFFTData::in
fftw_real * in
the input, output and power_spectrum arrays
Definition realFFTData.H:41
realFFTData::compPowerSpec
int compPowerSpec()
This function computes the power spectrum and returns the max bin.
realFFT
class realFFT controls fftw plans and executes fwd/inv transforms
Definition realFFT.H:32
realFFT::invTransform
void invTransform()
Inverse transform the data (out to in)
realFFT::fwdTransform
void fwdTransform()
Forward transform the data (in to out)