AdvancedController Class Reference

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Detailed Description

With this controller you can set the running time of the annealing process in advance. It works the following way: the controller measures a kind of divergence. The divergence is the difference of the average cost of the recently found solutions the cost of the best found one. In case this divergence is greater than a given threshold, then we decrease the annealing factor, that is we cool the system faster. In case the divergence is lower than the threshold, then we increase the temperature. The threshold is a function of the elapsed time which reaches zero at the desired end time. #include <lemon/simann.h>

Inheritance diagram for AdvancedController:

[legend]

List of all members.

Public Member Functions
	AdvancedController (double _end_time, double _alpha=0.2, double _beta=0.9, double _gamma=1.6, double _ann_fact=0.9999)
	Constructor.
void	init ()
	Does initializations before each run.
void	acceptEvent ()
	This is called when a neighbouring state gets accepted.
bool	next ()
	Decides whether to continue the annealing process or not.
bool	accept ()
	Decides whether to accept the current solution or not.
virtual	~AdvancedController ()
	Destructor.
Private Member Functions
virtual double	threshold (double time)
	Calculates the threshold value.
Private Attributes
Timer	timer
	Timer class to measure the elapsed time.
double	alpha
	Parameter used to calculate the running average.
double	beta
	Parameter used to decrease the annealing factor.
double	gamma
	Parameter used to increase the temperature.
double	end_time
	The time at the end of the algorithm.
double	start_time
	The time at the start of the algorithm.
double	start_threshold
	Starting threshold.
double	avg_cost
	Average cost of recent solutions.
double	temp
	Temperature.
double	ann_fact
	Annealing factor.
double	init_ann_fact
	Initial annealing factor.
bool	start
	True when the annealing process has been started.

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Constructor & Destructor Documentation

AdvancedController	(	double	_end_time,
		double	_alpha = 0.2,
		double	_beta = 0.9,
		double	_gamma = 1.6,
		double	_ann_fact = 0.9999
	)			[inline]

Parameters:

	_end_time	running time in seconds
	_alpha	parameter used to calculate the running average
	_beta	parameter used to decrease the annealing factor
	_gamma	parameter used to increase the temperature
	_ann_fact	initial annealing factor

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Member Function Documentation

virtual double threshold

(

double

time

)

[inline, private, virtual]

Parameters:

time

the elapsed time in seconds