cosmotool/sample/test_fft_calls.cpp

#include "yorick.hpp"
#include <gsl/gsl_rng.h>
#include <iostream>
#include <cmath>
#include "fourier/euclidian.hpp"

using namespace CosmoTool;
using namespace std;

double spectrum_generator(double k)
{
  return 1/(0.1+pow(k, 3.0));
}

int main()
{
  EuclidianFourierTransform_2d<double> dft(128,128,1.0,1.0);
  EuclidianSpectrum_1D<double> spectrum(spectrum_generator);
  double volume = 128*128;
  gsl_rng *rng = gsl_rng_alloc(gsl_rng_default);

  dft.realSpace().eigen().setRandom();
  dft.analysis();
  cout << "Map dot-product = " << dft.realSpace().dot_product(dft.realSpace()) << endl;
  cout << "Fourier dot-product = " << dft.fourierSpace().dot_product(dft.fourierSpace()).real()*volume << endl;
  dft.synthesis();
  cout << "Resynthesis dot-product = " << dft.realSpace().dot_product(dft.realSpace()) << endl;

  dft.realSpace().scale(2.0);
  dft.fourierSpace().scale(0.2);

  SpectrumFunction<double>::FourierMapPtr m = spectrum.newRandomFourier(rng, dft.fourierSpace()); 
  dft.fourierSpace() = *m.get();
  dft.synthesis();

  uint32_t dims[2] = { 128, 128 };
  CosmoTool::saveArray("generated_map.nc", dft.realSpace().data(), dims, 2);
  
  return 0;

}