/* make_fourier_data.cc

generates a list of doubles to mimic the uniform
sampling of a time-dependent signal.

output file: fourier_raw.dat

output file is eventually read in by
fourier.cc to generate the digital
fourier transform of the data created in the
present code.

*/


#include<iostream>
#include <cmath>
#include <fstream>

using namespace std;


double func(double x);

int main()
{

  int i_max = 1000 ; // max number of points to sample
  //  int i,n;
  //  double data[n];
  double y = 0.0;
  double step = 0.001; // time between samples, user units
                       // (step)^-1 is the sampling rate
  const double two_pi = 2*acos(-1.0);


  ofstream outfile;
  outfile.open("fourier_raw.dat");  // store output data

       /*

       for (i = 0; i < i_max; ++i)
         {
           data[i] = 0.0;
         }
     

       for (i = n / 3; i < 2 * n / 3; i++)
         {
           data[i] = 1.0;
         }
     
       for (i = 0; i < n; i++)
         {
	   printf ("%d %e\n", i, data[i]);
         }
       printf ("\n");


       */


  for (int k = 0 ; k < i_max; ++k){   // "sample" the waveform

    y = func(step *k*two_pi);
    outfile << k << "\t" << y << endl;
  }


  outfile.close();

  cout << "data written to fourier_raw.dat"  << endl; 
  return 0;
}


double func(double x){     // sampled waveform
  //  return cos(5.0*x) + cos(20.0*x);
  return cos(5.0*x) + cos(40.0*x);
}