ec.eval
Class SlaveMonitor

java.lang.Object
  ec.eval.SlaveMonitor

public class SlaveMonitor
extends java.lang.Object

SlaveMonitor.java The SlaveMonitor is the main tool used by the evolutionary computation process to synchronize the work of multiple threads (for example, for different slaves). The monitor is in charge of keeping track of all the slaves (either those that are busy with various jobs they have received, or those that are available to perform jobs on behalf of the main evolutionary process). Additionally, the monitor provides methods to schedule a job to be executed by the next available slave, as well as a mechanism to wait until all jobs have been finished.

Version:

1.0

Author:

Liviu Panait

Field Summary

static java.lang.String	P_EVALCOMPRESSION
static java.lang.String	P_EVALMASTERPORT
static java.lang.String	P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE
java.net.ServerSocket	servSock The socket where slaves connect.
EvolutionState	state
boolean	useCompression Indicates whether compression is used over the socket IO streams.

Constructor Summary

SlaveMonitor(boolean showDebugInfo, int maxJobsPerSlave)
Simple constructor that initializes the data structures for keeping track of the state of each slave.

Method Summary

boolean	evaluatedIndividualAvailable()
QueueIndividual	getEvaluatedIndividual() Blocks until an individual comes available
QueueIndividual	getNextAvailableIndividual() Returns null if there is no such individual, else returns the next individual.
void	notifyMonitor(java.lang.Object monitor)
int	numAvailableSlaves() Returns the number of available slave (not busy)
void	registerSlave(EvolutionState state, java.lang.String name, java.net.Socket socket, java.io.DataOutputStream out, java.io.DataInputStream in) Registers a new slave with the monitor.
void	scheduleJobForEvaluation(EvolutionState state, Job job) Schedules a job for execution on one of the available slaves.
void	shutdown() Shuts down the slave monitor (also shuts down all slaves).
void	unregisterSlave(ec.eval.SlaveConnection slave) Unregisters a dead slave from the monitor.
void	waitForAllSlavesToFinishEvaluating(EvolutionState state) This method returns only when all slaves have finished the jobs that they were assigned.
Individual	waitForIndividual()
boolean	waitOnMonitor(java.lang.Object monitor)

Methods inherited from class java.lang.Object

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

Field Detail

P_EVALMASTERPORT

public static final java.lang.String P_EVALMASTERPORT

See Also:

Constant Field Values

P_EVALCOMPRESSION

public static final java.lang.String P_EVALCOMPRESSION

See Also:

Constant Field Values

P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE

public static final java.lang.String P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE

See Also:

Constant Field Values

state

public EvolutionState state

servSock

public java.net.ServerSocket servSock

The socket where slaves connect.

useCompression

public boolean useCompression

Indicates whether compression is used over the socket IO streams.

Constructor Detail

SlaveMonitor

public SlaveMonitor(boolean showDebugInfo,
                    int maxJobsPerSlave)

Simple constructor that initializes the data structures for keeping track of the state of each slave. The constructor receives two parameters: a boolean flag indicating whether the system should display information that is useful for debugging, and the maximum load per slave (the maximum number of jobs that a slave can be entrusted with at each time).

Method Detail

waitOnMonitor

public boolean waitOnMonitor(java.lang.Object monitor)

notifyMonitor

public void notifyMonitor(java.lang.Object monitor)

registerSlave

public void registerSlave(EvolutionState state,
                          java.lang.String name,
                          java.net.Socket socket,
                          java.io.DataOutputStream out,
                          java.io.DataInputStream in)

Registers a new slave with the monitor. Upon registration, a slave is marked as available for jobs.

unregisterSlave

public void unregisterSlave(ec.eval.SlaveConnection slave)

Unregisters a dead slave from the monitor.

shutdown

public void shutdown()

Shuts down the slave monitor (also shuts down all slaves).

scheduleJobForEvaluation

public void scheduleJobForEvaluation(EvolutionState state,
                                     Job job)

Schedules a job for execution on one of the available slaves. The monitor waits until at least one slave is available to perform the job.

waitForAllSlavesToFinishEvaluating

public void waitForAllSlavesToFinishEvaluating(EvolutionState state)

This method returns only when all slaves have finished the jobs that they were assigned. While this method waits, new jobs can be assigned to the slaves. This method is usually invoked from MasterProblem.finishEvaluating. You should not abuse using this method: if there are two evaluation threads, where one of them waits until all jobs are finished, while the second evaluation thread keeps posting jobs to the slaves, the first thread might have to wait until the second thread has had all its jobs finished.

evaluatedIndividualAvailable

public boolean evaluatedIndividualAvailable()

numAvailableSlaves

public int numAvailableSlaves()

Returns the number of available slave (not busy)

getNextAvailableIndividual

public QueueIndividual getNextAvailableIndividual()

Returns null if there is no such individual, else returns the next individual.

getEvaluatedIndividual

public QueueIndividual getEvaluatedIndividual()

Blocks until an individual comes available

waitForIndividual

public Individual waitForIndividual()