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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