KokkosFFT::fftfreq

template<typename ExecutionSpace, typename RealType>
auto KokkosFFT::fftfreq(const ExecutionSpace&, const std::size_t n, const RealType d = 1.0)

Return the DFT sample frequencies.

Template Parameters:

  • ExecutionSpace – The type of Kokkos execution space

  • RealType – The floating point precision type to represent frequencies

Parameters:

  • exec_space – [in] Kokkos execution space

  • n – [in] Window length

  • d – [in] Sample spacing (default, 1)

Returns:

Sampling frequency

Examples

 1#include <iostream>
 2#include <Kokkos_Core.hpp>
 3#include <Kokkos_Complex.hpp>
 4#include <KokkosFFT.hpp>
 5
 6/// \brief Example of fftfreq usage in documentation
 7/// For n = 10, the output is
 8/// freq = [0 0.1 0.2 0.3 0.4 -0.5 -0.4 -0.3 -0.2 -0.1]
 9int main(int argc, char* argv[]) {
10  Kokkos::ScopeGuard guard(argc, argv);
11  using ExecutionSpace = Kokkos::DefaultExecutionSpace;
12
13  const int n0 = 10;
14  ExecutionSpace exec;
15  auto freq = KokkosFFT::fftfreq<ExecutionSpace, double>(exec, n0);
16
17  auto h_freq = Kokkos::create_mirror_view_and_copy(Kokkos::HostSpace{}, freq);
18  for (int i = 0; i < freq.extent_int(0); ++i) {
19    std::cout << " " << h_freq(i);
20  }
21  std::cout << std::endl;
22
23  return 0;
24}

Expected output:

0 0.1 0.2 0.3 0.4 -0.5 -0.4 -0.3 -0.2 -0.1