TSlidingWindow.h

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/* +---------------------------------------------------------------------------+
         |                     Mobile Robot Programming Toolkit (MRPT)               |
         |                          http://www.mrpt.org/                             |
         |                                                                           |
         | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file        |
         | See: http://www.mrpt.org/Authors - All rights reserved.                   |
         | Released under BSD License. See details in http://www.mrpt.org/License    |
         +---------------------------------------------------------------------------+ */

#ifndef TSLIDINGWINDOW_H
#define TSLIDINGWINDOW_H

#include <mrpt/utils/CLoadableOptions.h>
#include <mrpt/graphslam/link_pragmas.h>

#include <algorithm> // std::transform
#include <cmath> // sqrt
#include <functional> // std::bind2nd
#include <numeric> // std::accumulate
#include <string>
#include <vector>

namespace mrpt { namespace graphslam {

/**\brief Class to monitor the evolution of a statistical quantity.
 *
 * ## Description
 *
 * Keeps track of the last N incoming measurements of the quantity at hand and
 * upon request returns statistical properties of these measurements (mean,
 * median, etc.)
 *
 * Class also contains methods for evaluating incoming measurements (whether to
 * accept or reject those)
 *
 * ### .ini Configuration Parameters </b>
 *
 * \htmlinclude graphslam-engine_config_params_preamble.txt
 *
 * - \b sliding_win_size
 *   + \a Default value : 10
 *   + \a Required      : FALSE
 *   + \a Description   : How many of the latest measurements to take into
 *   account when computing the relevant statistics
 *
 * \ingroup mrpt_graphslam_grp
 */
struct GRAPHSLAM_IMPEXP TSlidingWindow: public mrpt::utils::CLoadableOptions {
        public:
                TSlidingWindow(std::string name="window");
                ~TSlidingWindow();
                /**\brief Return the current median value.  */
                double getMedian();
                /**\brief Return the current mean value.  */
                double getMean();
                /**\brief Return the Standard deviation of the current measurement vector*/
                double getStdDev();
                /**\brief Determine whether the incoming measurement is inside the
                 * [-3sigma, +3sigma] boundaries from the current mean value.
                 *
                 * \return True if it's inside the uncertainty boundaries
                 */
                bool evaluateMeasurementInGaussian(double measurement);
                /**\brief Determine whether the incoming measurement is over the current
                 * mean value.
                 *
                 * \return True if it's above the mean
                 */
                bool evaluateMeasurementAbove(double value);
                /**\brief Determine whether the incoming measurement is *less or equal* to
                 * the current mean value.
                 *
                 * \return True if it's <= to the mean
                 */
                bool evaluateMeasurementBelow(double value);
                /**\brief Update the sliding window by appending a new measurement */
                void addNewMeasurement(double measurement);
                /** Resize the window.
                 *
                 * \note Method affects the underlying vector only if the new_size
                 * specified has already been reached
                 */
                void resizeWindow(size_t new_size);
                void loadFromConfigFile(
                                const mrpt::utils::CConfigFileBase &source,
                                const std::string &section);
                // TODO - make it use the boundaries
                void    dumpToTextStream(mrpt::utils::CStream &out) const;

                /**\brief Return the size of the window
                 */
                size_t getWindowSize() const;
                /**\brief Check if the window has reached its limit. This limit is set by
                 * the user via the resizeWindow method.
                 *
                 * \sa resizeWindow
                 */
                bool windowIsFull() const;

        private:
                size_t m_win_size;
                std::vector<double> m_measurements_vec;

                /**\brief Name of the TSlidingWindow Instance at hand */
                std::string m_name;

                double m_mean_cached; /**< Cached mean value */
                double m_median_cached; /**< Cached median value */
                double m_std_dev_cached; /**< Cached version of the standard deviation */
                bool m_mean_updated; /**< Is the mean up-to-date? */
                bool m_median_updated; /**< Is the median up-to-date? */
                bool m_std_dev_updated; /**< Is the standard deviation up-to-date? */

                /**\brief flag is raised the first time that
                 * TSlidingWindow::addNewMeasurement is
                 * called
                 */
                bool m_is_initialized;
};

} } // end of namespaces
#endif /* end of include guard: TSLIDINGWINDOW_H */