linearApproximationPolicy_tpl.h

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/***************************************************************************
 *   Copyright (C) 2005 by Christophe GONZALES and Pierre-Henri WUILLEMIN  *
 *   {prenom.nom}_at_lip6.fr                                               *
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// Help IDE parsers
#include <agrum/core/approximations/linearApproximationPolicy.h>

namespace gum {

  // Class constructor
  template < typename GUM_SCALAR >
  LinearApproximationPolicy< GUM_SCALAR >::LinearApproximationPolicy(
     GUM_SCALAR low, GUM_SCALAR high, GUM_SCALAR eps) :
      ApproximationPolicy< GUM_SCALAR >(),
      _lowLimit(low), _highLimit(high), _epsilon(eps) {
    if (eps <= 0) { GUM_ERROR(OutOfBounds, "Epsilon must be >0"); }

    _computeNbInterval();
  }

  // Copy constructor.
  template < typename GUM_SCALAR >
  LinearApproximationPolicy< GUM_SCALAR >::LinearApproximationPolicy(
     const LinearApproximationPolicy< GUM_SCALAR >* md) :
      ApproximationPolicy< GUM_SCALAR >(md),
      _epsilon(md->_epsilon), _nbInterval(md->_nbInterval) {}


  // @brief Convert value to his approximation.
  template < typename GUM_SCALAR >
  INLINE GUM_SCALAR LinearApproximationPolicy< GUM_SCALAR >::fromExact(
     const GUM_SCALAR& value) const {
    return __decode(GUM_SCALAR(encode(value)));
  }

  // @brief Combine using addition with the given gum::ApproximationPolicy.
  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineAdd(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit = _lowLimit + lap->lowLimit();
      GUM_SCALAR newLowLimit = _lowLimit + lap->lowLimit();

      GUM_SCALAR newVal = _lowLimit + lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit + lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit + lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineSub(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit = _lowLimit - lap->lowLimit();
      GUM_SCALAR newLowLimit = _lowLimit - lap->lowLimit();

      GUM_SCALAR newVal = _lowLimit - lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit - lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit - lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineMult(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit = _lowLimit * lap->lowLimit();
      GUM_SCALAR newLowLimit = _lowLimit * lap->lowLimit();

      GUM_SCALAR newVal = _lowLimit * lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit * lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit * lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineDiv(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit = _lowLimit / lap->lowLimit();
      GUM_SCALAR newLowLimit = _lowLimit / lap->lowLimit();

      GUM_SCALAR newVal = _lowLimit / lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit / lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit / lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineMax(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit =
         _lowLimit > lap->lowLimit() ? _lowLimit : lap->lowLimit();
      GUM_SCALAR newLowLimit =
         _lowLimit > lap->lowLimit() ? _lowLimit : lap->lowLimit();

      GUM_SCALAR newVal =
         _lowLimit > lap->highLimit() ? _lowLimit : lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit > lap->lowLimit() ? _highLimit : lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit > lap->highLimit() ? _highLimit : lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::combineMin(
     const ApproximationPolicy< GUM_SCALAR >* ap) {
    try {
      const LinearApproximationPolicy< GUM_SCALAR >* lap =
         dynamic_cast< const LinearApproximationPolicy< GUM_SCALAR >* >(ap);

      GUM_SCALAR newHighLimit =
         _lowLimit < lap->lowLimit() ? _lowLimit : lap->lowLimit();
      GUM_SCALAR newLowLimit =
         _lowLimit < lap->lowLimit() ? _lowLimit : lap->lowLimit();

      GUM_SCALAR newVal =
         _lowLimit < lap->highLimit() ? _lowLimit : lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit < lap->lowLimit() ? _highLimit : lap->lowLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;

      newVal = _highLimit < lap->highLimit() ? _highLimit : lap->highLimit();

      if (newHighLimit < newVal) newHighLimit = newVal;

      if (newLowLimit > newVal) newLowLimit = newVal;
    } catch (const std::bad_cast&) {}
  }

  // Convert value to his approximation. This method is slower than @ref
  // fromExact since it verifies the bounds
  template < typename GUM_SCALAR >
  INLINE GUM_SCALAR LinearApproximationPolicy< GUM_SCALAR >::safeFromExact(
     const GUM_SCALAR& value) {
    if (value > this->_highLimit) {
      GUM_ERROR(OutOfUpperBound, "Value asked is higher than high limit");
    }

    if (value < this->_lowLimit) {
      GUM_ERROR(OutOfLowerBound, "Value asked is lower than low limit");
    }

    return fromExact(value);
  }

  // Convert value to approximation representation
  template < typename GUM_SCALAR >
  INLINE Idx LinearApproximationPolicy< GUM_SCALAR >::encode(
     const GUM_SCALAR& value) const {
// we keep the bounds checked in debug mode
#ifdef GUM_DEBUG_MODE
    if (value > this->_highLimit) {
      GUM_TRACE(value << " not in (" << this->_lowLimit << "-" << this->_highLimit
                      << ")");
      GUM_ERROR(OutOfUpperBound, "Value asked is higher than High limit");
    }

    if (value < this->_lowLimit) {
      GUM_TRACE(value << " not in (" << this->_lowLimit << "-" << this->_highLimit
                      << ")");
      GUM_ERROR(OutOfLowerBound, "Value asked is lower than low limit");
    }

#endif   // GUM_DEBUG_MODE
    return __encode(value);
  }

  // Convert approximation representation to value
  template < typename GUM_SCALAR >
  INLINE GUM_SCALAR
         LinearApproximationPolicy< GUM_SCALAR >::decode(Idx representation) const {
    if (representation > _nbInterval) {
      GUM_ERROR(OutOfUpperBound,
                "Interval Number asked is higher than total number of interval");
    }

    return __decode(GUM_SCALAR(representation));
  }

  // Sets approximation factor
  template < typename GUM_SCALAR >
  INLINE void
     LinearApproximationPolicy< GUM_SCALAR >::setEpsilon(const GUM_SCALAR& e) {
    _epsilon = e;
    _computeNbInterval();
  }

  // set bounds in a whole
  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::setLimits(
     const GUM_SCALAR& newLowLimit, const GUM_SCALAR& newHighLimit) {
    if (newLowLimit > newHighLimit) {
      GUM_ERROR(OutOfBounds, "Asked low value is higher than asked high value");
    }

    _lowLimit = newLowLimit;
    _highLimit = newHighLimit;
    _computeNbInterval();
  }

  // Sets lowest possible value
  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::setLowLimit(
     const GUM_SCALAR& newLowLimit) {
    if (newLowLimit > this->_highLimit) {
      GUM_ERROR(OutOfUpperBound, "Value asked is higher than High limit");
    }

    _lowLimit = newLowLimit;

    _computeNbInterval();
  }

  // Gets lowest possible value
  template < typename GUM_SCALAR >
  INLINE const GUM_SCALAR&
               LinearApproximationPolicy< GUM_SCALAR >::lowLimit() const {
    return _lowLimit;
  }

  // Sets Highest possible value
  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::setHighLimit(
     const GUM_SCALAR& newHighLimit) {
    if (newHighLimit < this->_lowLimit) {
      GUM_ERROR(OutOfLowerBound, "Value asked is lower than low limit");
    }

    _highLimit = newHighLimit;

    _computeNbInterval();
  }

  // Gets Highest possible value
  template < typename GUM_SCALAR >
  INLINE const GUM_SCALAR&
               LinearApproximationPolicy< GUM_SCALAR >::highLimit() const {
    return _highLimit;
  }

  // Concretely computes the approximate representation
  template < typename GUM_SCALAR >
  INLINE Idx LinearApproximationPolicy< GUM_SCALAR >::__encode(
     const GUM_SCALAR& value) const {
    if (value <= this->_lowLimit) return 0;

    if (value >= this->_highLimit) return _nbInterval;

    return 1 + Idx(((value - this->_lowLimit) / this->_epsilon));
  }

  // Concretely computes the approximate value from representation
  template < typename GUM_SCALAR >
  INLINE GUM_SCALAR LinearApproximationPolicy< GUM_SCALAR >::__decode(
     const GUM_SCALAR& representation) const {
    if (representation == 0) return this->_lowLimit;

    if (representation == _nbInterval) return this->_highLimit;

    return (GUM_SCALAR)(((representation * this->_epsilon) - (this->_epsilon / 2))
                        + this->_lowLimit);
  }

  // get the number of interval
  template < typename GUM_SCALAR >
  INLINE void LinearApproximationPolicy< GUM_SCALAR >::_computeNbInterval() {
    _nbInterval = 1 + Idx((this->_highLimit - this->_lowLimit) / this->_epsilon);
  }
}   // namespace gum