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Gecode::Int::GCC::Bnd

Gecode::Int::GCC::Bnd< Card > Class Template Reference
[Integer propagators]

Bounds consistent global cardinality propagator. More...

#include <gcc.hh>

List of all members.

Public Member Functions

virtual Actor * copy (Space &home)
 Copy propagator during cloning.
virtual PropCost cost (const Space &home, const ModEventDelta &med) const
 Cost funtion.
virtual void reschedule (Space &home)
 Schedule function.
virtual ExecStatus propagate (Space &home, const ModEventDelta &med)
 Perform propagation.
virtual size_t dispose (Space &home)
 Destructor.

Static Public Member Functions

static ExecStatus post (Home home, ViewArray< IntView > &x, ViewArray< Card > &k)
 Post propagator for views x and cardinalities k.

Protected Member Functions

 Bnd (Space &home, Bnd< Card > &p)
 Constructor for cloning p.
ExecStatus pruneCards (Space &home)
 Prune cardinality variables with 0 maximum occurrence.
ExecStatus lbc (Space &home, int &nb, HallInfo hall[], Rank rank[], int mu[], int nu[])
 Lower Bounds constraint (LBC) stating $ \forall j \in \{0, \dots, |k|-1\}: \#\{i\in\{0, \dots, |x| - 1\} | x_i = card(k_j)\} \geq min(k_j)$ Hence the lbc constraints the variables such that every value occurs at least as often as specified by its lower cardinality bound.
ExecStatus ubc (Space &home, int &nb, HallInfo hall[], Rank rank[], int mu[], int nu[])
 Upper Bounds constraint (UBC) stating $ \forall j \in \{0, \dots, |k|-1\}: \#\{i\in\{0, \dots, |x| - 1\} | x_i = card(k_j)\} \leq max(k_j)$ Hence the ubc constraints the variables such that no value occurs more often than specified by its upper cardinality bound.
 Bnd (Home home, ViewArray< IntView > &, ViewArray< Card > &, bool, bool)
 Constructor for posting.

Protected Attributes

ViewArray< IntView > x
 Views on which to perform bounds-propagation.
ViewArray< IntView > y
 Views on which to perform value-propagation (subset of x).
ViewArray< Card > k
 Array containing either fixed cardinalities or CardViews.
PartialSum< Card > lps
 Data structure storing the sum of the views lower bounds Necessary for reasoning about the interval capacities in the propagation algorithm.
PartialSum< Card > ups
 Data structure storing the sum of the views upper bounds.
bool card_fixed
 Stores whether cardinalities are all assigned.
bool skip_lbc
 Stores whether the minium required occurences of the cardinalities are all zero. If so, we do not need to perform lower bounds propagation.

Detailed Description

template<class Card>
class Gecode::Int::GCC::Bnd< Card >

Bounds consistent global cardinality propagator.

The algorithm is taken from: Claude-Guy Quimper, Peter van Beek, Alejandro López-Ortiz, Alexander Golynski, and Sayyed Bashir Sadjad. An Efficient Bounds Consistency Algorithm for the Global Cardinality Constraint, CP 2003, pages 600-614.

This implementation uses the code that is provided by Peter Van Beek: http://ai.uwaterloo.ca/~vanbeek/software/software.html The code here has only been slightly modified to fit Gecode (taking idempotent/non-idempotent propagation into account) and uses a more efficient layout of datastructures (keeping the number of different arrays small).

The Bnd class is used to post the propagator and BndImp is the actual implementation taking shared variables into account.

Requires 

 #include <gecode/int/gcc.hh>

Definition at line 113 of file gcc.hh.

Constructor & Destructor Documentation

template<class Card >
Gecode::Int::GCC::Bnd< Card >::Bnd ( Space &  home,
Bnd< Card > &  p 
) [inline, protected]

Constructor for cloning p.

Definition at line 56 of file bnd.hpp.

template<class Card >
Gecode::Int::GCC::Bnd< Card >::Bnd ( Home  home,
ViewArray< IntView > &  x0,
ViewArray< Card > &  k0,
bool  cf,
bool  nolbc 
) [inline, protected]

Constructor for posting.

Definition at line 45 of file bnd.hpp.

Member Function Documentation

template<class Card >
ExecStatus Gecode::Int::GCC::Bnd< Card >::pruneCards ( Space &  home  )  [inline, protected]

Prune cardinality variables with 0 maximum occurrence.

Definition at line 562 of file bnd.hpp.

template<class Card >
ExecStatus Gecode::Int::GCC::Bnd< Card >::lbc ( Space &  home,
int &  nb,
HallInfo  hall[],
Rank  rank[],
int  mu[],
int  nu[] 
) [inline, protected]

Lower Bounds constraint (LBC) stating $ \forall j \in \{0, \dots, |k|-1\}: \#\{i\in\{0, \dots, |x| - 1\} | x_i = card(k_j)\} \geq min(k_j)$ Hence the lbc constraints the variables such that every value occurs at least as often as specified by its lower cardinality bound.

Parameters:
home current space
nb denotes number of unique bounds
hall contains information about the hall structure of the problem (cf. HallInfo)
rank ranking information about the variable bounds (cf. Rank)
mu permutation $ \mu $ such that $ \forall i\in \{0, \dots, |x|-2\}: max(x_{\mu(i)}) \leq max(x_{\mu(i+1)})$
nu permutation $ \nu $ such that $ \forall i\in \{0, \dots, |x|-2\}: min(x_{\mu(i)}) \leq min(x_{\mu(i+1)})$

Definition at line 100 of file bnd.hpp.

template<class Card >
ExecStatus Gecode::Int::GCC::Bnd< Card >::ubc ( Space &  home,
int &  nb,
HallInfo  hall[],
Rank  rank[],
int  mu[],
int  nu[] 
) [inline, protected]

Upper Bounds constraint (UBC) stating $ \forall j \in \{0, \dots, |k|-1\}: \#\{i\in\{0, \dots, |x| - 1\} | x_i = card(k_j)\} \leq max(k_j)$ Hence the ubc constraints the variables such that no value occurs more often than specified by its upper cardinality bound.

Parameters:
home current space
nb denotes number of unique bounds
hall contains information about the hall structure of the problem (cf. HallInfo)
rank ranking information about the variable bounds (cf. Rank)
mu permutation $ \mu $ such that $ \forall i\in \{0, \dots, |x|-2\}: max(x_{\mu(i)}) \leq max(x_{\mu(i+1)})$
nu permutation $ \nu $ such that $ \forall i\in \{0, \dots, |x|-2\}: min(x_{\mu(i)}) \leq min(x_{\mu(i+1)})$

Definition at line 404 of file bnd.hpp.

template<class Card >
Actor * Gecode::Int::GCC::Bnd< Card >::copy ( Space &  home  )  [inline, virtual]

Copy propagator during cloning.

Implements Gecode::Actor.

Definition at line 75 of file bnd.hpp.

template<class Card >
PropCost Gecode::Int::GCC::Bnd< Card >::cost ( const Space &  home,
const ModEventDelta &  med 
) const [inline, virtual]

Cost funtion.

Implements Gecode::Propagator.

Definition at line 81 of file bnd.hpp.

template<class Card >
void Gecode::Int::GCC::Bnd< Card >::reschedule ( Space &  home  )  [inline, virtual]

Schedule function.

Implements Gecode::Propagator.

Definition at line 93 of file bnd.hpp.

template<class Card >
ExecStatus Gecode::Int::GCC::Bnd< Card >::propagate ( Space &  home,
const ModEventDelta &  med 
) [inline, virtual]

Perform propagation.

Implements Gecode::Propagator.

Definition at line 596 of file bnd.hpp.

template<class Card >
size_t Gecode::Int::GCC::Bnd< Card >::dispose ( Space &  home  )  [inline, virtual]

Destructor.

Reimplemented from Gecode::Actor.

Definition at line 66 of file bnd.hpp.

template<class Card >
ExecStatus Gecode::Int::GCC::Bnd< Card >::post ( Home  home,
ViewArray< IntView > &  x,
ViewArray< Card > &  k 
) [inline, static]

Post propagator for views x and cardinalities k.

Definition at line 808 of file bnd.hpp.

Member Data Documentation

template<class Card>
ViewArray<IntView> Gecode::Int::GCC::Bnd< Card >::x [protected]

Views on which to perform bounds-propagation.

Definition at line 116 of file gcc.hh.

template<class Card>
ViewArray<IntView> Gecode::Int::GCC::Bnd< Card >::y [protected]

Views on which to perform value-propagation (subset of x).

Definition at line 118 of file gcc.hh.

template<class Card>
ViewArray<Card> Gecode::Int::GCC::Bnd< Card >::k [protected]

Array containing either fixed cardinalities or CardViews.

Definition at line 120 of file gcc.hh.

template<class Card>
PartialSum<Card> Gecode::Int::GCC::Bnd< Card >::lps [protected]

Data structure storing the sum of the views lower bounds Necessary for reasoning about the interval capacities in the propagation algorithm.

Definition at line 126 of file gcc.hh.

template<class Card>
PartialSum<Card> Gecode::Int::GCC::Bnd< Card >::ups [protected]

Data structure storing the sum of the views upper bounds.

Definition at line 128 of file gcc.hh.

template<class Card>
bool Gecode::Int::GCC::Bnd< Card >::card_fixed [protected]

Stores whether cardinalities are all assigned.

If all cardinalities are assigned the propagation algorithm only has to perform propagation for the upper bounds.

Definition at line 135 of file gcc.hh.

template<class Card>
bool Gecode::Int::GCC::Bnd< Card >::skip_lbc [protected]

Stores whether the minium required occurences of the cardinalities are all zero. If so, we do not need to perform lower bounds propagation.

Definition at line 141 of file gcc.hh.

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