1 | /*
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2 | Copyright 2006 by Sean Luke
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3 | Licensed under the Academic Free License version 3.0
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4 | See the file "LICENSE" for more information
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5 | */
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6 |
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7 |
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8 | package ec;
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9 |
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10 | /*
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11 | * Exchanger.java
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12 | *
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13 | * Created: Tue Aug 10 21:59:17 1999
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14 | * By: Sean Luke
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15 | */
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16 |
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17 | /**
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18 | * The Exchanger is a singleton object whose job is to (optionally)
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19 | * perform individual exchanges between subpopulations in the run,
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20 | * or exchange individuals with other concurrent evolutionary run processes,
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21 | * using sockets or whatever. Keep in mind that other processes may go down,
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22 | * or be started up from checkpoints, etc.
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23 | *
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24 | * @author Sean Luke
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25 | * @version 1.0
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26 | */
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27 |
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28 | public abstract class Exchanger implements Singleton
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29 | {
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30 | /** Initializes contacts with other processes, if that's what you're doing. Called at the beginning of an evolutionary run, before a population is set up. */
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31 | public void initializeContacts(EvolutionState state) { }
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32 |
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33 | /** Initializes contacts with other processes, if that's what you're doing. Called after restarting from a checkpoint. */
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34 | public void reinitializeContacts(EvolutionState state) { }
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35 |
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36 | /** Performs exchanges after the population has been evaluated but before it has been bred,
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37 | once every generation (or pseudogeneration). */
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38 | public abstract Population preBreedingExchangePopulation(EvolutionState state);
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39 |
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40 | /** Performs exchanges after the population has been bred but before it has been evaluated,
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41 | once every generation (or pseudogeneration). */
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42 | public abstract Population postBreedingExchangePopulation(EvolutionState state);
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43 |
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44 | /** Called after preBreedingExchangePopulation(...) to evaluate whether or not
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45 | the exchanger wishes the run to shut down (with ec.EvolutionState.R_FAILURE) --
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46 | returns a String (which will be printed out as a message) if the exchanger
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47 | wants to shut down, else returns null if the exchanger does NOT want to shut down.
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48 | Why would you want to shut down?
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49 | This would happen for two reasons. First, another process might have found
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50 | an ideal individual and the global run is now over. Second, some network
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51 | or operating system error may have occurred and the system needs to be shut
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52 | down gracefully. Note that if the exchanger wants to shut down, the system
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53 | will shut down REGARDLESS of whether or not the user stated
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54 | ec.EvolutionState.quitOnRunComplete. */
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55 | public abstract String runComplete(EvolutionState state);
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56 |
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57 | /** Closes contacts with other processes, if that's what you're doing. Called at the end of an evolutionary run. result is either ec.EvolutionState.R_SUCCESS or ec.EvolutionState.R_FAILURE, indicating whether or not an ideal individual was found. */
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58 | public void closeContacts(EvolutionState state, int result) { }
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59 | }
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