Bounds consistent distinct propagator. More...
#include <distinct.hh>
Public Member Functions | |
virtual ExecStatus | propagate (Space &home, const ModEventDelta &med) |
Perform propagation. More... | |
virtual PropCost | cost (const Space &home, const ModEventDelta &med) const |
Cost function. More... | |
virtual Actor * | copy (Space &home, bool share) |
Copy propagator during cloning. More... | |
virtual size_t | dispose (Space &home) |
Destructor. More... | |
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ModEventDelta | modeventdelta (void) const |
Return the modification event delta. More... | |
virtual ExecStatus | advise (Space &home, Advisor &a, const Delta &d) |
Advise function. More... | |
double | afc (const Space &home) const |
Return the accumlated failure count. More... | |
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Static Public Member Functions | |
static ExecStatus | post (Home home, ViewArray< View > &x) |
Post propagator for view array x. More... | |
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static void * | operator new (size_t s, Space &home) |
Allocate memory from space. More... | |
static void | operator delete (void *p, Space &home) |
No-op for exceptions. More... | |
Protected Member Functions | |
Bnd (Home home, ViewArray< View > &x) | |
Constructor for posting. More... | |
Bnd (Space &home, bool share, Bnd< View > &p) | |
Constructor for cloning p. More... | |
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Propagator (Home home) | |
Constructor for posting. More... | |
Propagator (Space &home, bool share, Propagator &p) | |
Constructor for cloning p. More... | |
Propagator * | fwd (void) const |
Return forwarding pointer during copying. More... | |
Protected Attributes | |
ViewArray< View > | x |
Views on which to perform bounds-propagation. More... | |
ViewArray< View > | y |
Views on which to perform value-propagation (subset of x ) More... | |
int | min_x |
Minimum (approximation) of view in x. More... | |
int | max_x |
Maximum (approximation) of view in x. More... | |
Bounds consistent distinct propagator.
The propagator uses staging: first it uses naive value-based propagation and only then uses bounds consistent propagation. Due to using naive value-based propagation, the propagator might actually achieve stronger consistency than just bounds consistency.
The algorithm is taken from: A. Lopez-Ortiz, C.-G. Quimper, J. Tromp, and P. van Beek. A fast and simple algorithm for bounds consistency of the alldifferent constraint. IJCAI-2003.
This implementation uses the code that is provided by Peter Van Beek: http://ai.uwaterloo.ca/~vanbeek/software/software.html The code (originally by John Tromp) 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).
Requires
Definition at line 129 of file distinct.hh.
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Cost function.
If in stage for naive value propagation, the cost is low linear. Otherwise it is low quadratic.
Implements Gecode::Propagator.
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Views on which to perform bounds-propagation.
Definition at line 132 of file distinct.hh.
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Views on which to perform value-propagation (subset of x
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Definition at line 134 of file distinct.hh.
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Minimum (approximation) of view in x.
Definition at line 136 of file distinct.hh.
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Maximum (approximation) of view in x.
Definition at line 138 of file distinct.hh.