Local Search Filters are used for fast neighbor pruning. Filtering a move is done in several phases:
- in the Relax phase, filters determine which parts of their internals will be changed by the candidate, and modify intermediary State
- in the Accept phase, filters check that the candidate is feasible,
- if the Accept phase succeeds, the solver may decide to trigger a Synchronize phase that makes filters change their internal representation to the last candidate,
- otherwise (Accept fails or the solver does not want to synchronize), a Revert phase makes filters erase any intermediary State generated by the Relax and Accept phases. A given filter has phases called with the following pattern: (Relax.Accept.Synchronize | Relax.Accept.Revert | Relax.Revert)*. Filters's Revert() is always called in the reverse order their Accept() was called, to allow late filters to use state done/undone by early filters' Accept()/Revert().
Definition at line 3093 of file constraint_solveri.h.
#include <constraint_solveri.h>
◆ Accept()
| virtual bool operations_research::LocalSearchFilter::Accept |
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const Assignment * | delta, |
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const Assignment * | deltadelta, |
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int64_t | objective_min, |
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int64_t | objective_max ) |
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pure virtual |
Accepts a "delta" given the assignment with which the filter has been synchronized; the delta holds the variables which have been modified and their new value. If the filter represents a part of the global objective, its contribution must be between objective_min and objective_max. Sample: supposing one wants to maintain a[0,1] + b[0,1] <= 1, for the assignment (a,1), (b,0), the delta (b,1) will be rejected but the delta (a,0) will be accepted.
- Todo
- (user): Remove arguments when there are no more need for those.
Implemented in operations_research::BasePathFilter.
◆ Commit()
| virtual void operations_research::LocalSearchFilter::Commit |
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const Assignment * | , |
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const Assignment * | ) |
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inlinevirtual |
◆ GetAcceptedObjectiveValue()
| virtual int64_t operations_research::LocalSearchFilter::GetAcceptedObjectiveValue |
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const |
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inlinevirtual |
◆ GetSynchronizedObjectiveValue()
| virtual int64_t operations_research::LocalSearchFilter::GetSynchronizedObjectiveValue |
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const |
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inlinevirtual |
◆ IsIncremental()
| virtual bool operations_research::LocalSearchFilter::IsIncremental |
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const |
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inlinevirtual |
◆ Relax()
| virtual void operations_research::LocalSearchFilter::Relax |
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const Assignment * | , |
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const Assignment * | ) |
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inlinevirtual |
◆ Reset()
| virtual void operations_research::LocalSearchFilter::Reset |
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inlinevirtual |
◆ Revert()
| virtual void operations_research::LocalSearchFilter::Revert |
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inlinevirtual |
◆ Synchronize()
| virtual void operations_research::LocalSearchFilter::Synchronize |
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const Assignment * | assignment, |
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const Assignment * | delta ) |
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pure virtual |
Synchronizes the filter with the current solution, delta being the difference with the solution passed to the previous call to Synchronize() or IncrementalSynchronize(). 'delta' can be used to incrementally synchronizing the filter with the new solution by only considering the changes in delta.
Implemented in operations_research::IntVarLocalSearchFilter.
The documentation for this class was generated from the following file:
