lasp/cpp_src/dsp/lasp_avpowerspectra.cpp

/* #define DEBUGTRACE_ENABLED */
#include "lasp_avpowerspectra.h"
#include "debugtrace.hpp"
#include "lasp_mathtypes.h"
#include <stdexcept>

using rte = std::runtime_error;

PowerSpectra::PowerSpectra(const us nfft, const Window::WindowType w)
    : PowerSpectra(Window::create(w, nfft)) {}

PowerSpectra::PowerSpectra(const vd &window)
    : nfft(window.size()), _fft(nfft), _window(window) {

  d win_pow = arma::sum(window % window) / window.size();

  /* Scale fft such that power is easily computed */
  _scale_fac = 2.0 / (win_pow * (d)nfft * (d)nfft);

  DEBUGTRACE_PRINT(nfft);
  DEBUGTRACE_PRINT(win_pow);
}

ccube PowerSpectra::compute(const dmat &input) {

  /// Run very often. Silence this one.
  /* DEBUGTRACE_ENTER; */

  dmat input_tmp = input;

  // Multiply each column of the inputs element-wise with the window.
  input_tmp.each_col() %= _window;

  cmat rfft = _fft.fft(input_tmp);

  ccube output(rfft.n_rows, input.n_cols, input.n_cols);
  for (us i = 0; i < input.n_cols; i++) {
    /// This one can be run in parallel without any problem. Note that it is
    /// the inner loop that is run in parallel.
#pragma omp parallel for
    for (us j = 0; j < input.n_cols; j++) {
      output.slice(j).col(i) =
          _scale_fac * (rfft.col(i) % arma::conj(rfft.col(j)));

      output.slice(j).col(i)(0) /= 2;
      output.slice(j).col(i)(nfft / 2) /= 2;
    }
  }
  return output;
}

AvPowerSpectra::AvPowerSpectra(const us nfft, const Window::WindowType w,
                               const d overlap_percentage,
                               const d time_constant_times_fs)
    : _ps(nfft, w) {

  DEBUGTRACE_ENTER;
  if (overlap_percentage >= 100 || overlap_percentage < 0) {
    throw rte("Overlap percentage should be >= 0 and < 100");
  }

  _overlap_keep = (nfft * overlap_percentage) / 100;
  DEBUGTRACE_PRINT(_overlap_keep);
  if (_overlap_keep >= nfft) {
    throw rte("Overlap is too high. Results in no jump. Please "
              "choose a smaller overlap percentage or a higher nfft");
  }
  if (time_constant_times_fs < 0) {
    _mode = Mode::Averaging;
  } else if (time_constant_times_fs == 0) {
    _mode = Mode::Spectrogram;
  } else {
    _mode = Mode::Leaking;
    _alpha = d_exp(-static_cast<d>((nfft - _overlap_keep)/time_constant_times_fs));
    DEBUGTRACE_PRINT(_alpha);
  }
}
void AvPowerSpectra::reset() {
  _timeBuf.reset();
  _est.reset();
  n_averages=0;

}

ccube AvPowerSpectra::compute(const dmat &timedata) {

  DEBUGTRACE_ENTER;
  DEBUGTRACE_PRINT(timedata.n_rows);
  DEBUGTRACE_PRINT(_ps.nfft);

  _timeBuf.push(timedata);

  bool run_once = false;
  while (_timeBuf.size() >= _ps.nfft) {

    DEBUGTRACE_PRINT((int)_mode);

    dmat samples = _timeBuf.pop(_ps.nfft, _overlap_keep);

    switch (_mode) {
    case (Mode::Spectrogram):
      DEBUGTRACE_PRINT("Spectrogram mode");
      _est = _ps.compute(samples);
      break;
    case (Mode::Averaging):
      DEBUGTRACE_PRINT("Averaging mode");
      n_averages++;
      if (n_averages == 1) {
        _est = _ps.compute(samples);
      } else {
        _est = (static_cast<d>(n_averages - 1) / n_averages) * _est +
               _ps.compute(samples) / n_averages;
      }
      break;
    case (Mode::Leaking):
      DEBUGTRACE_PRINT("Leaking mode");
      if (arma::size(_est) == arma::size(0, 0, 0)) {
        _est = _ps.compute(samples);
      } else {
        _est = _alpha * _est + (1 - _alpha) * _ps.compute(samples);
      }
      break;
    } // end switch mode
    run_once = true;
  }

  /// Return a copy of current estimator in case we have done one update.
  /// Othewise, we return an empty ccube.
  return run_once ? _est : ccube();
}
ccube AvPowerSpectra::get_est() const {
  return _est;
}