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;
+}
+