| 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 | * SelectionMethod.java
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| 12 | *
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| 13 | * Created: Mon Aug 30 19:19:56 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 | * A SelectionMethod is a BreedingSource which provides direct IMMUTABLE pointers
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| 19 | * to original individuals in an old population, not fresh mutable copies.
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| 20 | * If you use a SelectionMethod as your BreedingSource, you must
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| 21 | * SelectionMethods might include Tournament Selection, Fitness Proportional Selection, etc.
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| 22 | * SelectionMethods don't have parent sources.
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| 23 | *
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| 24 | <p><b>Typical Number of Individuals Produced Per <tt>produce(...)</tt> call</b><br>
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| 25 | Always 1.
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| 26 |
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| 27 | * @author Sean Luke
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| 28 | * @version 1.0
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| 29 | */
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| 30 |
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| 31 | public abstract class SelectionMethod extends BreedingSource
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| 32 | {
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| 33 | public static final int INDS_PRODUCED = 1;
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| 34 |
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| 35 | /** Returns 1 (the typical default value) */
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| 36 | public int typicalIndsProduced() { return INDS_PRODUCED; }
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| 37 |
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| 38 | /** A default version of produces -- this method always returns
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| 39 | true under the assumption that the selection method works
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| 40 | with all Fitnesses. If this isn't the case, you should override
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| 41 | this to return your own assessment. */
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| 42 | public boolean produces(final EvolutionState state,
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| 43 | final Population newpop,
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| 44 | final int subpopulation,
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| 45 | final int thread)
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| 46 | {
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| 47 | return true;
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| 48 | }
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| 49 |
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| 50 |
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| 51 | /** A default version of prepareToProduce which does nothing. */
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| 52 | public void prepareToProduce(final EvolutionState s,
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| 53 | final int subpopulation,
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| 54 | final int thread)
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| 55 | { return; }
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| 56 |
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| 57 | /** A default version of finishProducing, which does nothing. */
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| 58 | public void finishProducing(final EvolutionState s,
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| 59 | final int subpopulation,
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| 60 | final int thread)
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| 61 | { return; }
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| 62 |
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| 63 | public int produce(final int min,
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| 64 | final int max,
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| 65 | final int start,
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| 66 | final int subpopulation,
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| 67 | final Individual[] inds,
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| 68 | final EvolutionState state,
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| 69 | final int thread)
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| 70 | {
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| 71 | int n=INDS_PRODUCED;
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| 72 | if (n<min) n = min;
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| 73 | if (n>max) n = max;
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| 74 |
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| 75 | for(int q=0;q<n;q++)
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| 76 | inds[start+q] = state.population.subpops[subpopulation].
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| 77 | individuals[produce(subpopulation,state,thread)];
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| 78 | return n;
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| 79 | }
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| 80 |
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| 81 | /** An alternative form of "produce" special to Selection Methods;
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| 82 | selects an individual from the given subpopulation and
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| 83 | returns its position in that subpopulation. */
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| 84 | public abstract int produce(final int subpopulation,
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| 85 | final EvolutionState state,
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| 86 | final int thread);
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| 87 | }
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| 88 |
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| 89 |
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| 90 |
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