ec.eval

Class Slave

java.lang.Object

ec.eval.Slave

public class Slave
extends java.lang.Object

Slave.java

Slave is the main entry point for a slave evaluation process. The slave works with a master process, receiving individuals from the master, evaluating them, and reporting the results back to the master, thus enabling distributed evolution.

Slave replicates most of the functionality of the ec.Evolve class, for example in terms of parameters and checkpointing. This is mostly because it needs to bootstrap and set up the EvolutionState in much the same way that ec.Evolve does. Additionally, depending on settings below, the Slave may act like a mini-evolver on the individuals it receives from the master.

Like ec.Evolve, Slave is run with like this:

java ec.eval.Slave -file parameter_file [-p parameter=value]*

This starts a new slave, using the parameter file parameter_file. The user can provide optional overriding parameters on the command-line with the -p option.

Slaves need to know some things in order to run: the master's IP address and socket port number, whether to do compression, and whether or not to return individuals or just fitnesses. Unfortunately, Sun's CompressedInputStream/CompressedOutputStream is broken (it doesn't allow partial flushes, which is critical for doing compressed network streams). In order to do compression, you need to download the JZLIB library from the ECJ website or from http://www.jcraft.com/jzlib/ . ECJ will detect and use it automatically.

Slaves presently always run in single-threaded mode and receive their random number generator seed from the master. Thus they ignore any seed parameters given to them.

Slaves run in one of three modes:

• "Regular" mode, which does a loop where it receives N individuals, evaluates them, and returns either the individuals or their new fitnesses.

• "Regular Coevolutionary" mode, which does a loop where it receives N individuals to assess together in a single coevolutionary evaluation, evaluates them, and returns either the individuals or their new fitnesses (or only some fitnesses if only some are requested).

• "Evolve" mode, which does a loop where it receives N individuals, evaluates them, and if there's some more time left, does a little evolution on those individuals as if they were a population, then when the time is up, the current individuals in the population are returned in lieu of the original individuals. In this second form, individuals MUST be returned, not fitnesses. This mode is not available if you're doing coevolution.

Parameters

eval.slave-name String	(the slave's name, only for debugging purposes. If not specified, the slave makes one up.)
eval.master.host String	(the IP Address of the master.)
eval.master.port integer >= 1024	(the socket port number of the master.)
eval.compression bool = true or false (default)	(should we use compressed streams in communicating with the master?)
eval.run-evolve bool = true or false (default)	(should we immediately evaluate the individuals and return them (or their fitnesses), or if we have extra time (defined by eval.runtime), should we do a little evolution on our individuals first?)
eval.runtime integer > 0	(if eval.run-evolve is true, how long (in milliseconds wall-clock time) should we allow the individuals to evolve?)
eval.return-inds bool = true or false (default)	(should we return whole individuals or (if false) just the fitnesses of the individuals? This must be TRUE if eval.run-evolve is true.)
eval.one-shot bool = true (default) or false	(Should the slave quit when the master quits, or loop continuously in the background processing new masters?)

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	A_FILE The argument indicating that we're starting fresh from a new parameter file.
static boolean	oneShot
static java.lang.String	P_EVALCOMPRESSION
static java.lang.String	P_EVALMASTERHOST
static java.lang.String	P_EVALMASTERPORT
static java.lang.String	P_EVALSLAVENAME
static java.lang.String	P_MUZZLE
static java.lang.String	P_ONESHOT Should slave go into an infinite loop looking for new masters after the master has quit, or not?
static java.lang.String	P_RETURNINDIVIDUALS
static java.lang.String	P_RUNEVOLVE Should slave run its own evolutionary process?
static java.lang.String	P_RUNTIME Time to run evolution on the slaves in seconds
static java.lang.String	P_SILENT
static ThreadPool	pool
static boolean	runEvolve
static int	runTime
static int	slaveNum My unique slave number.
static int	SLEEP_TIME How long we sleep in between attempts to connect to the master (in milliseconds).
static byte	V_EVALUATEGROUPED
static byte	V_EVALUATESIMPLE
static byte	V_FITNESS
static byte	V_INDIVIDUAL
static byte	V_NOTHING
static byte	V_SHUTDOWN

Constructor Summary

Constructors

Constructor and Description
Slave()

Method Summary

Modifier and Type	Method and Description
static void	evaluateGroupedProblemForm(EvolutionState state, boolean returnIndividuals, java.io.DataInputStream dataIn, java.io.DataOutputStream dataOut)
static void	evaluateSimpleProblemForm(EvolutionState state, boolean returnIndividuals, java.io.DataInputStream dataIn, java.io.DataOutputStream dataOut, java.lang.String[] args)
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

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

Field Detail

P_EVALSLAVENAME

public static final java.lang.String P_EVALSLAVENAME

See Also:

Constant Field Values

P_EVALMASTERHOST

public static final java.lang.String P_EVALMASTERHOST

See Also:

Constant Field Values

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_RETURNINDIVIDUALS

public static final java.lang.String P_RETURNINDIVIDUALS

See Also:

Constant Field Values

P_SILENT

public static final java.lang.String P_SILENT

See Also:

Constant Field Values

P_MUZZLE

public static final java.lang.String P_MUZZLE

See Also:

Constant Field Values

V_NOTHING

public static final byte V_NOTHING

See Also:

Constant Field Values

V_INDIVIDUAL

public static final byte V_INDIVIDUAL

See Also:

Constant Field Values

V_FITNESS

public static final byte V_FITNESS

See Also:

Constant Field Values

V_SHUTDOWN

public static final byte V_SHUTDOWN

See Also:

Constant Field Values

V_EVALUATESIMPLE

public static final byte V_EVALUATESIMPLE

See Also:

Constant Field Values

V_EVALUATEGROUPED

public static final byte V_EVALUATEGROUPED

See Also:

Constant Field Values

A_FILE

public static final java.lang.String A_FILE

The argument indicating that we're starting fresh from a new parameter file.

See Also:

Constant Field Values

P_RUNTIME

public static final java.lang.String P_RUNTIME

Time to run evolution on the slaves in seconds

See Also:

Constant Field Values

runTime

public static int runTime

P_RUNEVOLVE

public static final java.lang.String P_RUNEVOLVE

Should slave run its own evolutionary process?

See Also:

Constant Field Values

runEvolve

public static boolean runEvolve

P_ONESHOT

public static final java.lang.String P_ONESHOT

Should slave go into an infinite loop looking for new masters after the master has quit, or not?

See Also:

Constant Field Values

oneShot

public static boolean oneShot

SLEEP_TIME

public static final int SLEEP_TIME

How long we sleep in between attempts to connect to the master (in milliseconds).

See Also:

Constant Field Values

pool

public static final ThreadPool pool

slaveNum

public static int slaveNum

My unique slave number. At present this is just used to define a unique name.

Constructor Detail

Slave

public Slave()

Method Detail

main

public static void main(java.lang.String[] args)

evaluateSimpleProblemForm

public static void evaluateSimpleProblemForm(EvolutionState state,
                                             boolean returnIndividuals,
                                             java.io.DataInputStream dataIn,
                                             java.io.DataOutputStream dataOut,
                                             java.lang.String[] args)

evaluateGroupedProblemForm

public static void evaluateGroupedProblemForm(EvolutionState state,
                                              boolean returnIndividuals,
                                              java.io.DataInputStream dataIn,
                                              java.io.DataOutputStream dataOut)