[52] | 1 | package geniusweb.boa.acceptancestrategy;
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| 2 |
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| 3 | import geniusweb.actions.Accept;
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| 4 | import geniusweb.actions.Action;
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| 5 | import geniusweb.actions.Offer;
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| 6 | import geniusweb.bidspace.BidsWithUtility;
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| 7 | import geniusweb.boa.BoaState;
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| 8 | import geniusweb.boa.biddingstrategy.TimeDependentBiddingStrategy;
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| 9 | import geniusweb.inform.Settings;
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| 10 | import geniusweb.issuevalue.Bid;
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| 11 | import geniusweb.profile.Profile;
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| 12 | import geniusweb.profile.utilityspace.LinearAdditive;
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| 13 | import geniusweb.profile.utilityspace.UtilitySpace;
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| 14 |
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| 15 | /**
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| 16 | * Simple implementation similar to the {@link TimeDependentBiddingStrategy}.
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| 17 | * Accepts if the last placed offer is ≥ {@link #p(double)}. Uses 4
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| 18 | * parameters:
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| 19 | * <ul>
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| 20 | * <li>e: the exponent for the target-utility function. See {@link #f(double)}
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| 21 | * <li>k: the constant for the target-utility function. See {@link #f(double)}
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| 22 | * <li>max: the maximum utility target used at t=0.
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| 23 | * <li>min: the minimum utility target used at t=1
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| 24 | * </ul>
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| 25 | */
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| 26 | public class TimeDependentAcceptanceStrategy implements AcceptanceStrategy {
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| 27 |
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| 28 | private transient Double min = null, max = null, e = null, k = null; // cache
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| 29 |
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| 30 | @Override
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| 31 | public Action filter(Action action, BoaState state) {
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| 32 | Offer lastOffer = state.getLastReceivedOffer();
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| 33 | if (lastOffer == null || !(action instanceof Offer))
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| 34 | return action;
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| 35 | Bid bid = lastOffer.getBid();
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| 36 | if (min == null || max == null || e == null || k == null) {
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| 37 | min = getMin(state);
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| 38 | max = getMax(state);
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| 39 | e = getE(state);
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| 40 | k = getK(state);
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| 41 | }
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| 42 | double targetUtil = p(
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| 43 | state.getProgress().get(System.currentTimeMillis()));
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| 44 | // we subtract epsilon because of rounding errors in computation.
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| 45 | if (((UtilitySpace) state.getProfile()).getUtility(bid)
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| 46 | .doubleValue() >= targetUtil - 0.0000001)
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| 47 | return new Accept(state.getSettings().getID(), bid);
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| 48 | return action;
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| 49 | }
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| 50 |
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| 51 | /**
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| 52 | * Overrideable for hard configuring this component.
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| 53 | *
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| 54 | * @param state the {@link BoaState}
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| 55 | * @return the parameter e for the time depemdency function
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| 56 | * {@link #f(double)}. The parameter is 1 by default, or the value
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| 57 | * for the "e" parameter in the {@link Settings} if available.
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| 58 | */
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| 59 | protected Double getE(BoaState state) {
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| 60 | return state.getSettings().getParameters().getDouble("e", 1d, 0d, 1d);
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| 61 | }
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| 62 |
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| 63 | /**
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| 64 | * Overrideable for hard configuring this component.
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| 65 | *
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| 66 | * @param state the {@link BoaState}
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| 67 | * @return the parameter k for the time depemdency function
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| 68 | * {@link #f(double)}. The parameter is 0 by default, or the value
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| 69 | * for the "k" parameter in the {@link Settings} if available.
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| 70 | */
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| 71 | protected Double getK(BoaState state) {
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| 72 | return state.getSettings().getParameters().getDouble("k", 0d, 0d, 1d);
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| 73 | }
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| 74 |
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| 75 | /**
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| 76 | * Overrideable for hard configuring this component.
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| 77 | *
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| 78 | * @param state the {@link BoaState}
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| 79 | * @return the min value for {@link #p(double)}. We use the "min" parameter
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| 80 | * in the {@link Settings} if available. If not available, the
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| 81 | * parameter is computed as the utility of the reservation bid. If
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| 82 | * there is no reservation bid, we use the minimum utility of the
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| 83 | * available profile.
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| 84 | */
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| 85 | protected Double getMin(BoaState state) {
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| 86 | Double val = state.getSettings().getParameters().getDouble("min", null,
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| 87 | 0d, 1d);
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| 88 | if (val != null)
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| 89 | return val;
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| 90 | // val=null, try the reservation bid
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| 91 | LinearAdditive profile = (LinearAdditive) state.getProfile();
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| 92 | if (profile.getReservationBid() != null) {
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| 93 | return profile.getUtility(profile.getReservationBid())
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| 94 | .doubleValue();
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| 95 | }
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| 96 |
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| 97 | return getBidspace(profile).getRange().getMin().doubleValue();
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| 98 | }
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| 99 |
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| 100 | /**
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| 101 | * Overrideable for hard configuring this component.
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| 102 | *
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| 103 | * @param state the {@link BoaState}
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| 104 | * @return the max value for {@link #p(double)}. We use the "max" parameter
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| 105 | * in the {@link Settings} if available. If not available, we use
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| 106 | * the maximum utility of the available profile.
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| 107 | */
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| 108 | protected Double getMax(BoaState state) {
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| 109 | Double val = state.getSettings().getParameters().getDouble("max", null,
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| 110 | 0d, 1d);
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| 111 | if (val != null)
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| 112 | return val;
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| 113 | UtilitySpace profile = (UtilitySpace) state.getProfile();
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| 114 | return getBidspace(profile).getRange().getMax().doubleValue();
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| 115 |
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| 116 | }
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| 117 |
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| 118 | /**
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| 119 | * factory method. Overridable for testing
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| 120 | *
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| 121 | * @param profile the profile to get a bidspace for
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| 122 | * @return {@link BidsWithUtility}
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| 123 | */
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| 124 | protected BidsWithUtility getBidspace(Profile profile) {
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| 125 | return new BidsWithUtility((LinearAdditive) profile);
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| 126 | }
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| 127 |
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| 128 | /**
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| 129 | * Makes sure the target utility with in the acceptable range according to
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| 130 | * the domain
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| 131 | *
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| 132 | * @param t the normalized current time in the negotiation, where t=9 at
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| 133 | * start of negotiation and t=1 at end of negotiation.
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| 134 | * @return double
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| 135 | */
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| 136 | private double p(double t) {
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| 137 | return this.min + (this.max - this.min) * (1.0 - f(t));
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| 138 | }
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| 139 |
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| 140 | /**
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| 141 | * From the paper:
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| 142 | *
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| 143 | * A wide range of time dependent functions can be defined by varying the
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| 144 | * way in which f(t) is computed. However, functions must ensure that 0 <=
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| 145 | * f(t) <= 1, f(0) = k, and f(1) = 1.
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| 146 | *
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| 147 | * That is, the offer will always be between the value range, at the
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| 148 | * beginning it will give the initial constant and when the deadline is
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| 149 | * reached, it will offer the reservation value.
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| 150 | *
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| 151 | * @param t the normalized current time in the negotiation, where t=9 at
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| 152 | * start of negotiation and t=1 at end of negotiation.
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| 153 | * @return
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| 154 | */
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| 155 | private double f(double t) {
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| 156 | return k + (1.0 - k) * Math.pow(t, 1.0 / e);
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| 157 | }
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| 158 |
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| 159 | } |
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