artis-star/src/artis-star/kernel/qss/Integrator.hpp

/**
 * @file kernel/qss/Integrator.hpp
 * @author The ARTIS Development Team
 * See the AUTHORS or Authors.txt file
 */

/*
 * ARTIS - the multimodeling and simulation environment
 * This file is a part of the ARTIS environment
 *
 * Copyright (C) 2013-2019 ULCO http://www.univ-littoral.fr
 *
 * This program 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.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef QSS_INTEGRATOR
#define QSS_INTEGRATOR

#include <artis-star/kernel/pdevs/Dynamics.hpp>
#include <artis-star/kernel/qss/Data.hpp>

namespace artis {
namespace qss {

struct IntegratorParameters {
  double x_0;
};

template<class Time>
class Integrator
    : public artis::pdevs::Dynamics<Time, Integrator<Time>, IntegratorParameters> {

  typedef enum {
    INIT,
    WAIT_FOR_QUANTA,
    WAIT_FOR_X_DOT,
    WAIT_FOR_BOTH,
    RUNNING
  } State;

public:
  enum inputs {
    QUANTA, X_DOT, RESET
  };

  enum outputs {
    OUT
  };

  typedef enum vars {
    VALUE
  } Observable;

  enum states {
    STATE,
    LAST_OUT_DATE,
    UP_THRESHOLD,
    DOWN_THRESHOLD,
    LAST_OUT_VALUE,
    INIT_VALUE,
    CURRENT_VALUE,
    EXPECTED_VALUE,
    ARCHIVE_X_DOT,
    ARCHIVE_DATE
  };

  Integrator(const std::string &name,
             const artis::pdevs::Context<Time, Integrator<Time>, IntegratorParameters> &context)
      :
      artis::pdevs::Dynamics<Time, Integrator<Time>, IntegratorParameters>(name,
                                                                           context) {
    DECLARE_STATES(int, ((STATE, &Integrator<Time>::_state)));
    DECLARE_STATES(typename Time::type,
                   ((LAST_OUT_DATE, &Integrator<Time>::_last_output_date)));
    DECLARE_STATES(double, ((UP_THRESHOLD, &Integrator<Time>::_up_threshold),
        (DOWN_THRESHOLD, &Integrator<Time>::_down_threshold),
        (LAST_OUT_VALUE, &Integrator<Time>::_last_output_value),
        (INIT_VALUE, &Integrator<Time>::_init_value),
        (CURRENT_VALUE, &Integrator<Time>::_current_value),
        (EXPECTED_VALUE, &Integrator<Time>::_expected_value)));
    DECLARE_STATES(std::vector<double>,
                   ((ARCHIVE_X_DOT, &Integrator<Time>::_archive_x_dot)));
    DECLARE_STATES(std::vector<typename Time::type>,
                   ((ARCHIVE_DATE, &Integrator<Time>::_archive_date)));

    this->input_ports({
                          {QUANTA, "quanta"},
                          {X_DOT, "x_dot"},
                          {RESET, "reset"}});
    this->output_port({OUT, "out"});
    this->observable({VALUE, "value"});

    _init_value = context.parameters().x_0;
  }

  virtual ~Integrator() {}

  virtual void dconf(typename Time::type t, typename Time::type e,
                     const common::Bag<Time> &bag) {
    dint(t);
    dext(t, e, bag);
  }

  virtual void dint(const typename Time::type &time) {
    switch (_state) {
    case RUNNING: {
      double last_derivative_value = _archive_x_dot.back();

      _last_output_value = _expected_value;
      _last_output_date = time;
      _archive_x_dot.clear();
      _archive_date.clear();
      _archive_x_dot.push_back(last_derivative_value);
      _archive_date.push_back(time);
      _current_value = _expected_value;
      _state = WAIT_FOR_QUANTA;
      break;
    }
    case INIT: {
      _state = WAIT_FOR_BOTH;
      _last_output_value = _current_value;
      _last_output_date = time;
      break;
    }
    default:assert(false);
    }
  }

  virtual void dext(const typename Time::type &t, const typename Time::type &e,
                    const common::Bag<Time> &bag) {
    bool reset = false;

    std::for_each(bag.begin(), bag.end(),
                  [this, t, e, &reset](const common::ExternalEvent<Time> &event) {
                    if (event.on_port(QUANTA)) {
                      QuantifierData data;

                      event.data()(data);
                      _up_threshold = data.up;
                      _down_threshold = data.down;
                      if (_state == WAIT_FOR_QUANTA) {
                        _state = RUNNING;
                      }
                      if (_state == WAIT_FOR_BOTH) {
                        _state = WAIT_FOR_X_DOT;
                      }
                    } else if (event.on_port(X_DOT)) {
                      DerivativeData data;

                      event.data()(data);
                      _archive_x_dot.push_back(data.x_dot);
                      _archive_date.push_back(t);
                      if (_state == WAIT_FOR_X_DOT) {
                        _state = RUNNING;
                      }
                      if (_state == WAIT_FOR_BOTH) {
                        _state = WAIT_FOR_QUANTA;
                      }
                    } else if (event.on_port(RESET)) {
                      IntegratorData data;

                      event.data()(data);
                      _current_value = data.value;
                      reset = true;
                      _archive_x_dot.clear();
                      _archive_date.clear();
                    }
                  });
    if (reset) {
      _state = INIT;
    } else {
      if (_state == RUNNING) {
        _current_value = current_value(t);
        _expected_value = expected_value(t);
      }
    }
  }

  virtual void start(const typename Time::type & /* time */) {
    _current_value = _init_value;
    _state = INIT;
  }

  virtual typename Time::type ta(const typename Time::type & /* time */) {
    double current_derivative;

    switch (_state) {
    case INIT:return 0;
    case RUNNING:

      assert(_archive_date.size() > 0);

      current_derivative = _archive_x_dot.back();
      if (current_derivative == 0) {
        return Time::infinity;
      }
      if (current_derivative > 0) {

        assert(_up_threshold - _current_value >= 0);

        return (_up_threshold - _current_value) / current_derivative;
      } else {

        assert(_down_threshold - _current_value <= 0);

        return (_down_threshold - _current_value) / current_derivative;
      }
    default:return Time::infinity;
    }
  }

  virtual common::Bag<Time> lambda(const typename Time::type & /* time */) const {
    common::Bag<Time> msgs;

    switch (_state) {
    case RUNNING: {
      const IntegratorData data = {_expected_value};

      msgs.push_back(common::ExternalEvent<Time>(OUT, data));
      break;
    }
    case INIT: {
      const IntegratorData data = {_current_value};

      msgs.push_back(common::ExternalEvent<Time>(OUT, data));
      break;
    }
    default:break;
    }
    return msgs;
  }

  virtual common::Value observe(const typename Time::type & /* t */,
                                unsigned int index) const {
    switch (index) {
    case VALUE:return (double) (_current_value);
    default:return common::Value();
    }
  }

private:
  double current_value(const typename Time::type &time) const {
    double val = _last_output_value;

    if (_archive_date.size() > 0) {
      for (size_t i = 0; i < _archive_date.size() - 1; i++) {
        val +=
            (_archive_date[i + 1] - _archive_date[i]) * _archive_x_dot[i];
      }
      val += (time - _archive_date.back()) * _archive_x_dot.back();
    }
    return val;
  }

  double expected_value(const typename Time::type & /* time */) const {
    double current_derivative = _archive_x_dot.back();

    if (current_derivative == 0) {
      return _current_value;
    } else if (current_derivative > 0) {
      return _up_threshold;
    }
    return _down_threshold;
  }

  int _state;

  typename Time::type _last_output_date;

  double _up_threshold;
  double _down_threshold;

  double _last_output_value;
  double _init_value;
  double _current_value;
  double _expected_value;

  std::vector<double> _archive_x_dot;
  std::vector<typename Time::type> _archive_date;
};

}
}

#endif