ExactBNdistance computes exactly the KL divergence betweens 2 BNs. More...

#include <exactBNdistance.h>

Inheritance diagram for gum::ExactBNdistance< GUM_SCALAR >:

Collaboration diagram for gum::ExactBNdistance< GUM_SCALAR >:

Public Member Functions
	ExactBNdistance (const IBayesNet< GUM_SCALAR > &P, const IBayesNet< GUM_SCALAR > &Q)
	constructor must give 2 BNs
	ExactBNdistance (const BNdistance< GUM_SCALAR > &kl)
	copy constructor
	~ExactBNdistance () override
	destructor
Complexity	difficulty () const
	return KL::Complexity::Heavy,KL::Complexity::Difficult,KL::Complexity::Correct depending on the BNs p and q
Accessors to results. The first call do the computations. The
others do not.
double	klPQ ()
Size	errorPQ ()
double	klQP ()
Size	errorQP ()
double	hellinger ()
double	bhattacharya ()
double	jsd ()
const IBayesNet< GUM_SCALAR > &	p () const
const IBayesNet< GUM_SCALAR > &	q () const

Protected Member Functions
void	computeKL_ () final
void	process_ ()

Protected Attributes
const IBayesNet< GUM_SCALAR > &	p_
const IBayesNet< GUM_SCALAR > &	q_
GUM_SCALAR	klPQ_
GUM_SCALAR	klQP_
Size	errorPQ_
Size	errorQP_
GUM_SCALAR	hellinger_
GUM_SCALAR	bhattacharya_
GUM_SCALAR	jsd_

Private Member Functions
bool	_checkCompatibility_ () const

Private Attributes
Complexity	_difficulty_
bool	_done_

Detailed Description

template<GUM_Numeric GUM_SCALAR>
class gum::ExactBNdistance< GUM_SCALAR >

ExactBNdistance computes exactly the KL divergence betweens 2 BNs.

ExactBNdistance should be used only if difficulty() gives an estimation ( KL_CORRECT ) of the needed time. KL.process() computes KL(P||Q) using klPQ() and KL(Q||P) using klQP(). The computations are made once. The second is for free :) ExactBNdistance allows as well to compute in the same time the Hellinger distance ( \(*\sqrt{\sum_i (\sqrt{p_i}-\sqrt{q_i})^2}\)) (Kokolakis and Nanopoulos, 2001).

It may happen that P*ln(P/Q) is not computable (Q=0 and P!=0). In such a case, KL keeps working but trace this error (errorPQ() and errorQP())? *

Warning: This ExactBNdistance should be use only if difficulty()==complexity::CORRECT or at most complexity::DIFFICULT ... snippets :
gum::KL base_kl(net1,net2);

if (base_kl.difficulty()!=KL::HEAVY) {

gum::ExactBNdistance kl(base_kl);

std::cout<<"KL net1||net2 :"<<kl.klPQ()<<std::endl;

} else {

gum::GibbsKL kl(base_kl);

std::cout<<"KL net1||net2 :"<<kl.klPQ()<<std::endl;

}

gum::ExactBNdistance
ExactBNdistance computes exactly the KL divergence betweens 2 BNs.
Definition exactBNdistance.h:89

Definition at line 89 of file exactBNdistance.h.

Constructor & Destructor Documentation

◆ ExactBNdistance() [1/2]

template<GUM_Numeric GUM_SCALAR>

gum::ExactBNdistance< GUM_SCALAR >::ExactBNdistance	(	const IBayesNet< GUM_SCALAR > &	P,
		const IBayesNet< GUM_SCALAR > &	Q )

constructor must give 2 BNs

Exceptions

gum::OperationNotAllowed if the 2 BNs have not the same domainSize or compatible node sets.

Definition at line 59 of file exactBNdistance_tpl.h.

                                                                                   :
      BNdistance< GUM_SCALAR >(P, Q) {
    GUM_CONSTRUCTOR(ExactBNdistance);
  }

References gum::BNdistance< GUM_SCALAR >::BNdistance(), and ExactBNdistance().

Referenced by ExactBNdistance(), ExactBNdistance(), and ~ExactBNdistance().

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◆ ExactBNdistance() [2/2]

template<GUM_Numeric GUM_SCALAR>

gum::ExactBNdistance< GUM_SCALAR >::ExactBNdistance ( const BNdistance< GUM_SCALAR > & kl )

explicit

copy constructor

Definition at line 66 of file exactBNdistance_tpl.h.

                                                                                   :
      BNdistance< GUM_SCALAR >(kl) {
    GUM_CONSTRUCTOR(ExactBNdistance);
  }

References gum::BNdistance< GUM_SCALAR >::BNdistance(), and ExactBNdistance().

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◆ ~ExactBNdistance()

template<GUM_Numeric GUM_SCALAR>

gum::ExactBNdistance< GUM_SCALAR >::~ExactBNdistance ( )

override

destructor

Definition at line 72 of file exactBNdistance_tpl.h.

                                                  {
    GUM_DESTRUCTOR(ExactBNdistance);
  }

References ExactBNdistance().

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Member Function Documentation

◆ _checkCompatibility_()

template<GUM_Numeric GUM_SCALAR>

bool gum::BNdistance< GUM_SCALAR >::_checkCompatibility_ ( ) const

privateinherited

Definition at line 145 of file BNdistance_tpl.h.

                                                            {
    // should not be used
    if (p_.size() != q_.size())
      GUM_ERROR(OperationNotAllowed,
                "BNdistance : the 2 BNs are not compatible (not the same size)")
 
    for (auto node: p_.nodes()) {
      const DiscreteVariable& vp = p_.variable(node);
      if (!q_.exists(vp.name())) {
        GUM_ERROR(OperationNotAllowed,
                  "BNdistance : the 2 BNs are not compatible (variable : " + vp.name() + ")");
      }
      const DiscreteVariable& vq = q_.variableFromName(vp.name());
      if (vp != vq)
        GUM_ERROR(OperationNotAllowed,
                  "BNdistance : the 2 BNs are not compatible "
                  "(not the same variable for the same name : "
                      + vp.toString() + "and " + vq.toString() + ")");
    }
 
    if (std::fabs(p_.log10DomainSize() - q_.log10DomainSize()) > 1e-14) {
      GUM_ERROR(OperationNotAllowed,
                "BNdistance : the 2 BNs are not compatible (not the same domainSize) : p="
                    << p_.log10DomainSize() << " q=" << q_.log10DomainSize() << " => "
                    << p_.log10DomainSize() - q_.log10DomainSize());
    }
 
    return true;
  }

References GUM_ERROR, gum::Variable::name(), p_, q_, and gum::DiscreteVariable::toString().

Referenced by BNdistance().

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◆ bhattacharya()

template<GUM_Numeric GUM_SCALAR>

double gum::BNdistance< GUM_SCALAR >::bhattacharya ( )

inherited

Returns: Bhattacharya distance (

See also: http://en.wikipedia.org/wiki/Bhattacharya_distance)

Definition at line 110 of file BNdistance_tpl.h.

                                                {
    process_();
    return bhattacharya_;
  }

References bhattacharya_, and process_().

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◆ computeKL_()

template<GUM_Numeric GUM_SCALAR>

void gum::ExactBNdistance< GUM_SCALAR >::computeKL_ ( )

finalprotectedvirtual

Reimplemented from gum::BNdistance< GUM_SCALAR >.

Definition at line 77 of file exactBNdistance_tpl.h.

                                                 {
    klPQ_ = klQP_ = hellinger_ = bhattacharya_ = jsd_ = (GUM_SCALAR)0.0;
    errorPQ_ = errorQP_ = 0;
 
    auto Ip = p_.completeInstantiation();
    auto Iq = q_.completeInstantiation();
 
    // map between p_ variables and q_ variables (using name of vars)
    HashTable< const DiscreteVariable*, const DiscreteVariable* > map;
 
    for (Idx ite = 0; ite < Ip.nbrDim(); ++ite) {
      map.insert(&Ip.variable(ite), &q_.variableFromName(Ip.variable(ite).name()));
    }
    GUM_SCALAR pp, pq, pmid, lpp, lpq, lpmid;
    for (Ip.setFirst(); !Ip.end(); ++Ip) {
      Iq.setValsFrom(map, Ip);
      pp    = p_.jointProbability(Ip);
      pq    = q_.jointProbability(Iq);
      pmid  = (pp + pq) / 2.0;
      lpmid = GUM_LOG2_OR_0(pmid);
      lpp   = GUM_LOG2_OR_0(pp);
      lpq   = GUM_LOG2_OR_0(pq);
 
 
      hellinger_ += std::pow(std::sqrt(pp) - std::sqrt(pq), 2);
      bhattacharya_ += std::sqrt(pp * pq);
 
      if (pp != (GUM_SCALAR)0.0) {
        if (pq != (GUM_SCALAR)0.0) {
          klPQ_ -= pp * (lpq - lpp);   // log2(pq / pp);
        } else {
          errorPQ_++;
        }
      }
 
      if (pq != (GUM_SCALAR)0.0) {
        if (pp != (GUM_SCALAR)0.0) {
          klQP_ -= pq * (lpp - lpq);   // log2(pp / pq);
        } else {
          errorQP_++;
        }
      }
      if (pmid != (GUM_SCALAR)0.0) {
        jsd_ += pp * lpp + pq * lpq
              - (pp + pq) * lpmid;   // pp* log2(pp / pmid) + pq * log2(pq / pmid);
      }
    }
    jsd_ /= 2.0;
    hellinger_    = std::sqrt(hellinger_);
    bhattacharya_ = -std::log(bhattacharya_);
  }

References gum::BNdistance< GUM_SCALAR >::bhattacharya_, gum::BNdistance< GUM_SCALAR >::errorPQ_, gum::BNdistance< GUM_SCALAR >::errorQP_, GUM_LOG2_OR_0, gum::BNdistance< GUM_SCALAR >::hellinger_, gum::HashTable< Key, Val >::insert(), gum::BNdistance< GUM_SCALAR >::jsd_, gum::BNdistance< GUM_SCALAR >::klPQ_, gum::BNdistance< GUM_SCALAR >::klQP_, gum::BNdistance< GUM_SCALAR >::p_, and gum::BNdistance< GUM_SCALAR >::q_.

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◆ difficulty()

template<GUM_Numeric GUM_SCALAR>

Complexity gum::BNdistance< GUM_SCALAR >::difficulty ( ) const

inherited

return KL::Complexity::Heavy,KL::Complexity::Difficult,KL::Complexity::Correct depending on the BNs p and q

Definition at line 87 of file BNdistance_tpl.h.

                                                        {
    return _difficulty_;
  }

References _difficulty_.

◆ errorPQ()

template<GUM_Numeric GUM_SCALAR>

Size gum::BNdistance< GUM_SCALAR >::errorPQ ( )

inherited

Returns: the number of errors while processing divergence KL(P||Q)

Definition at line 122 of file BNdistance_tpl.h.

                                         {
    process_();
    return errorPQ_;
  }

References errorPQ_, and process_().

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◆ errorQP()

template<GUM_Numeric GUM_SCALAR>

Size gum::BNdistance< GUM_SCALAR >::errorQP ( )

inherited

Returns: the number of errors while processing divergence KL(Q||P)

Definition at line 128 of file BNdistance_tpl.h.

                                         {
    process_();
    return errorQP_;
  }

References errorQP_, and process_().

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◆ hellinger()

template<GUM_Numeric GUM_SCALAR>

double gum::BNdistance< GUM_SCALAR >::hellinger ( )

inherited

Returns: hellinger distance (

See also: http://en.wikipedia.org/wiki/Hellinger_distance)

Definition at line 104 of file BNdistance_tpl.h.

                                             {
    process_();
    return hellinger_;
  }

References hellinger_, and process_().

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◆ jsd()

template<GUM_Numeric GUM_SCALAR>

double gum::BNdistance< GUM_SCALAR >::jsd ( )

inherited

Returns: Jensen-Shannon divergence(

See also: https://en.wikipedia.org/wiki/Jensen%E2%80%93Shannon_divergence)

Definition at line 116 of file BNdistance_tpl.h.

                                       {
    process_();
    return jsd_;
  }

References jsd_, and process_().

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◆ klPQ()

template<GUM_Numeric GUM_SCALAR>

double gum::BNdistance< GUM_SCALAR >::klPQ ( )

inherited

Returns: divergence KL(P||Q)

Definition at line 92 of file BNdistance_tpl.h.

                                        {
    process_();
    return klPQ_;
  }

References klPQ_, and process_().

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◆ klQP()

template<GUM_Numeric GUM_SCALAR>

double gum::BNdistance< GUM_SCALAR >::klQP ( )

inherited

Returns: divergence KL(Q||P)

Definition at line 98 of file BNdistance_tpl.h.

                                        {
    process_();
    return klQP_;
  }

References klQP_, and process_().

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◆ p()

template<GUM_Numeric GUM_SCALAR>

const IBayesNet< GUM_SCALAR > & gum::BNdistance< GUM_SCALAR >::p ( ) const

inherited

Returns: p

Definition at line 134 of file BNdistance_tpl.h.

                                                                   {
    return p_;
  }

References p_.

Referenced by gum::GibbsBNdistance< GUM_SCALAR >::GibbsBNdistance().

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◆ process_()

template<GUM_Numeric GUM_SCALAR>

void gum::BNdistance< GUM_SCALAR >::process_ ( )

protectedinherited

Definition at line 177 of file BNdistance_tpl.h.

                                          {
    if (!_done_) {
      computeKL_();
      _done_ = true;
    }
  }

References _done_, and computeKL_().

Referenced by bhattacharya(), errorPQ(), errorQP(), hellinger(), jsd(), klPQ(), and klQP().

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◆ q()

template<GUM_Numeric GUM_SCALAR>

const IBayesNet< GUM_SCALAR > & gum::BNdistance< GUM_SCALAR >::q ( ) const

inherited

Returns: q

Definition at line 139 of file BNdistance_tpl.h.

                                                                   {
    return q_;
  }

References q_.

Member Data Documentation

◆ _difficulty_

template<GUM_Numeric GUM_SCALAR>

Complexity gum::BNdistance< GUM_SCALAR >::_difficulty_

privateinherited

Definition at line 171 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), and difficulty().

◆ _done_

template<GUM_Numeric GUM_SCALAR>

bool gum::BNdistance< GUM_SCALAR >::_done_

privateinherited

Definition at line 172 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), and process_().

◆ bhattacharya_

template<GUM_Numeric GUM_SCALAR>

GUM_SCALAR gum::BNdistance< GUM_SCALAR >::bhattacharya_

protectedinherited

Definition at line 166 of file BNdistance.h.

Referenced by bhattacharya(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), and gum::GibbsBNdistance< GUM_SCALAR >::computeKL_().

◆ errorPQ_

template<GUM_Numeric GUM_SCALAR>

Size gum::BNdistance< GUM_SCALAR >::errorPQ_

protectedinherited

Definition at line 162 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and errorPQ().

◆ errorQP_

template<GUM_Numeric GUM_SCALAR>

Size gum::BNdistance< GUM_SCALAR >::errorQP_

protectedinherited

Definition at line 163 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and errorQP().

◆ hellinger_

template<GUM_Numeric GUM_SCALAR>

GUM_SCALAR gum::BNdistance< GUM_SCALAR >::hellinger_

protectedinherited

Definition at line 165 of file BNdistance.h.

Referenced by gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and hellinger().

◆ jsd_

template<GUM_Numeric GUM_SCALAR>

GUM_SCALAR gum::BNdistance< GUM_SCALAR >::jsd_

protectedinherited

Definition at line 167 of file BNdistance.h.

Referenced by gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and jsd().

◆ klPQ_

template<GUM_Numeric GUM_SCALAR>

GUM_SCALAR gum::BNdistance< GUM_SCALAR >::klPQ_

protectedinherited

Definition at line 159 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and klPQ().

◆ klQP_

template<GUM_Numeric GUM_SCALAR>

GUM_SCALAR gum::BNdistance< GUM_SCALAR >::klQP_

protectedinherited

Definition at line 160 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and klQP().

◆ p_

template<GUM_Numeric GUM_SCALAR>

const IBayesNet< GUM_SCALAR >& gum::BNdistance< GUM_SCALAR >::p_

protectedinherited

Definition at line 156 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), _checkCompatibility_(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and p().

◆ q_

template<GUM_Numeric GUM_SCALAR>

const IBayesNet< GUM_SCALAR >& gum::BNdistance< GUM_SCALAR >::q_

protectedinherited

Definition at line 157 of file BNdistance.h.

Referenced by BNdistance(), BNdistance(), _checkCompatibility_(), gum::ExactBNdistance< GUM_SCALAR >::computeKL_(), gum::GibbsBNdistance< GUM_SCALAR >::computeKL_(), and q().

The documentation for this class was generated from the following files:

agrum/BN/algorithms/divergence/exactBNdistance.h
agrum/BN/algorithms/divergence/exactBNdistance_tpl.h

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ ExactBNdistance() [1/2]

◆ ExactBNdistance() [2/2]

◆ ~ExactBNdistance()

Member Function Documentation

◆ _checkCompatibility_()

◆ bhattacharya()

◆ computeKL_()

◆ difficulty()

◆ errorPQ()

◆ errorQP()

◆ hellinger()

◆ jsd()

◆ klPQ()

◆ klQP()

◆ p()

◆ process_()

◆ q()

Member Data Documentation

◆ _difficulty_

◆ _done_

◆ bhattacharya_

◆ errorPQ_

◆ errorQP_

◆ hellinger_

◆ jsd_

◆ klPQ_

◆ klQP_

◆ p_

◆ q_