Program Listing for File math_numeric.ipp

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// ---------------------------------------------------------------------
// This file is part of falcon-core.
//
// Copyright (C) 2015, 2016, 2017 Neuro-Electronics Research Flanders
//
// Falcon-server 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 3 of the License, or
// (at your option) any later version.
//
// Falcon-server 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 should have received a copy of the GNU General Public License
// along with falcon-core. If not, see <http://www.gnu.org/licenses/>.
// ---------------------------------------------------------------------

#include <vector>

template <typename T> std::vector<T> linspace(T min, T max, std::size_t n) {

  std::vector<T> result(n);
  auto step = (max - min) / (n - 1);

  for (std::size_t i = 0; i < n; i++) {
    result[i] = min + i * step;
  }

  return result;
}

template <typename ForwardIterator>
double nan_sum(ForwardIterator first, ForwardIterator last) {

  bool all_nan = true;
  double result = 0;

  for (; first != last; ++first) {
    if (!std::isnan(*first)) {
      result += *first;
      if (all_nan) {
        all_nan = false;
      }
    }
  }
  if (all_nan) {
    return std::nan("");
  }
  return result;
}

template <typename ForwardIterator>
double nan_mean(ForwardIterator first, ForwardIterator last, int n_elem_input) {

  std::size_t n_elem;
  double acc = 0;
  std::size_t nan_counter = 0;

  if (n_elem_input < 0) {
    n_elem = std::distance(first, last);
  } else {
    n_elem = n_elem_input;
  }

  if (n_elem < 1) {
    return 0;
  }

  std::size_t it_sum = 0;
  for (; first != last; ++first) {
    if (!std::isnan(*first)) {
      acc += *first;
      ++it_sum;
    } else {
      ++nan_counter;
    }
  }
  if (nan_counter == n_elem) {
    return std::nan("");
  }

  double ret = acc / (n_elem - nan_counter);

  return ret;
}