com.google.ortools.constraintsolver

Class LocalSearchFilter

java.lang.Object

com.google.ortools.constraintsolver.BaseObject

com.google.ortools.constraintsolver.LocalSearchFilter

Direct Known Subclasses:

IntVarLocalSearchFilter

public class LocalSearchFilter
extends BaseObject

Classes to which this template function can be applied to as of 04/2014.
Usage: LocalSearchOperator* op = MakeLocalSearchOperator<Relocate>(...);
class TwoOpt;
class Relocate;
class Exchange;
class Cross;
class MakeActiveOperator;
class MakeInactiveOperator;
class MakeChainInactiveOperator;
class SwapActiveOperator;
class ExtendedSwapActiveOperator;
class MakeActiveAndRelocate;
class RelocateAndMakeActiveOperator;
class RelocateAndMakeInactiveOperator;
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().

Field Summary

Fields inherited from class com.google.ortools.constraintsolver.BaseObject

swigCMemOwn

Constructor Summary

Constructors

Modifier	Constructor and Description
	LocalSearchFilter()
protected	LocalSearchFilter(long cPtr, boolean cMemoryOwn)

Method Summary

Modifier and Type	Method and Description
boolean	accept(Assignment delta, Assignment deltadelta, long objective_min, long objective_max) 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.
void	Commit(Assignment delta, Assignment deltadelta) Dual of Relax(), lets the filter know that the delta was accepted.
void	delete()
protected void	finalize()
long	getAcceptedObjectiveValue() Objective value from the last time Accept() was called and returned true.
protected static long	getCPtr(LocalSearchFilter obj)
long	getSynchronizedObjectiveValue() Objective value from last time Synchronize() was called.
boolean	isIncremental()
void	Relax(Assignment delta, Assignment deltadelta) Lets the filter know what delta and deltadelta will be passed in the next Accept().
void	Reset() Sets the filter to empty solution.
void	Revert() Cancels the changes made by the last Relax()/Accept() calls.
protected void	swigDirectorDisconnect()
protected static long	swigRelease(LocalSearchFilter obj)
void	swigReleaseOwnership()
void	swigTakeOwnership()
void	synchronize(Assignment assignment, Assignment delta) Synchronizes the filter with the current solution, delta being the difference with the solution passed to the previous call to Synchronize() or IncrementalSynchronize().

Methods inherited from class com.google.ortools.constraintsolver.BaseObject

getCPtr, swigRelease, toString

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

LocalSearchFilter

protected LocalSearchFilter(long cPtr,
                            boolean cMemoryOwn)

LocalSearchFilter

public LocalSearchFilter()

Method Detail

getCPtr

protected static long getCPtr(LocalSearchFilter obj)

swigRelease

protected static long swigRelease(LocalSearchFilter obj)

finalize

protected void finalize()

Overrides:

finalize in class BaseObject

delete

public void delete()

Overrides:

delete in class BaseObject

swigDirectorDisconnect

protected void swigDirectorDisconnect()

swigReleaseOwnership

public void swigReleaseOwnership()

swigTakeOwnership

public void swigTakeOwnership()

Relax

public void Relax(Assignment delta,
                  Assignment deltadelta)

Lets the filter know what delta and deltadelta will be passed in the next
Accept().

Commit

public void Commit(Assignment delta,
                   Assignment deltadelta)

Dual of Relax(), lets the filter know that the delta was accepted.

accept

public boolean accept(Assignment delta,
                      Assignment deltadelta,
                      long objective_min,
                      long objective_max)

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.

isIncremental

public boolean isIncremental()

synchronize

public void synchronize(Assignment assignment,
                        Assignment delta)

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.

Revert

public void Revert()

Cancels the changes made by the last Relax()/Accept() calls.

Reset

public void Reset()

Sets the filter to empty solution.

getSynchronizedObjectiveValue

public long getSynchronizedObjectiveValue()

Objective value from last time Synchronize() was called.

getAcceptedObjectiveValue

public long getAcceptedObjectiveValue()

Objective value from the last time Accept() was called and returned true.