[942] | 1 | #ifndef LEMON_SIMANN_H |
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| 2 | #define LEMON_SIMANN_H |
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[918] | 3 | |
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[942] | 4 | namespace lemon { |
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[918] | 5 | |
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[942] | 6 | const double INFTY = 1e24; |
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[918] | 7 | |
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[942] | 8 | class SimAnnBase { |
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[918] | 9 | public: |
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[942] | 10 | class Controller; |
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| 11 | private: |
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| 12 | Controller *controller; |
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| 13 | protected: |
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| 14 | double curr_cost; |
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| 15 | double prev_cost; |
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| 16 | double best_cost; |
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[918] | 17 | |
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[942] | 18 | virtual void mutate() = 0; |
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| 19 | virtual void revert() = 0; |
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| 20 | virtual void saveAsBest() = 0; |
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| 21 | public: |
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| 22 | SimAnnBase() { |
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| 23 | curr_cost = prev_cost = best_cost = INFTY; |
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| 24 | } |
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| 25 | void setController(Controller &_controller) { controller = &_controller; } |
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| 26 | double getBestCost() { return best_cost; } |
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| 27 | void run() { |
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| 28 | while (controller->next()) { |
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| 29 | mutate(); |
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| 30 | if (controller->accept(prev_cost - curr_cost)) { |
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| 31 | controller->acceptEvent(); |
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| 32 | if (curr_cost < best_cost) { |
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| 33 | saveAsBest(); |
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| 34 | controller->improveEvent(); |
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| 35 | } |
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| 36 | } |
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| 37 | else { |
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| 38 | revert(); |
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| 39 | controller->rejectEvent(); |
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| 40 | } |
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[918] | 41 | } |
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| 42 | } |
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| 43 | |
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[942] | 44 | class Controller { |
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| 45 | public: |
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| 46 | virtual void acceptEvent() {} |
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| 47 | virtual void improveEvent() {} |
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| 48 | virtual void rejectEvent() {} |
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| 49 | virtual bool next() = 0; |
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| 50 | virtual bool accept(double cost_diff) = 0; |
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| 51 | }; |
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| 52 | }; |
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[918] | 53 | |
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[942] | 54 | template <typename E> |
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| 55 | class SimAnn : public SimAnnBase { |
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| 56 | private: |
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| 57 | E *curr_ent; |
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| 58 | E *best_ent; |
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| 59 | public: |
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| 60 | SimAnn2() : SimAnnBase() {} |
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| 61 | void setEntity(E &Ent) { |
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| 62 | curr_ent = new E(Ent); |
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| 63 | best_ent = new E(Ent); |
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| 64 | } |
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| 65 | E getBestEntity() { return *best_ent; } |
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| 66 | void mutate() { |
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| 67 | curr_ent->mutate(); |
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| 68 | } |
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| 69 | void revert() { |
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| 70 | curr_ent->revert(); |
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| 71 | } |
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| 72 | void saveAsBest() { |
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| 73 | *best_ent = *curr_ent; |
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| 74 | best_cost = curr_cost; |
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| 75 | } |
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| 76 | }; |
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| 77 | |
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[956] | 78 | class EntitySkeleton { |
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[942] | 79 | public: |
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| 80 | // returns the new cost |
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| 81 | double mutate() { return 0.0; } |
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| 82 | // restores the entity to its previous state i.e. reverts the effects of |
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| 83 | // the last mutate() |
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| 84 | void revert() {} |
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| 85 | }; |
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| 86 | |
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[956] | 87 | class SimpleController : public SimAnnBase::Controller { |
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| 88 | public: |
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| 89 | long iter, last_impr, max_iter, max_no_impr; |
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| 90 | double temp, annealing_factor; |
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| 91 | MyController() { |
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| 92 | iter = last_impr = 0; |
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| 93 | max_iter = 500000; |
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| 94 | max_no_impr = 20000; |
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| 95 | annealing_factor = 0.9999; |
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| 96 | temp = 1000; |
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| 97 | } |
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| 98 | void acceptEvent() { |
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| 99 | iter++; |
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| 100 | } |
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| 101 | void improveEvent() { |
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| 102 | last_impr = iter; |
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| 103 | } |
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| 104 | void rejectEvent() { |
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| 105 | iter++; |
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| 106 | } |
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| 107 | bool next() { |
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| 108 | temp *= annealing_factor; |
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| 109 | bool quit = (iter > max_iter) || (iter - last_impr > max_no_impr); |
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| 110 | return !quit; |
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| 111 | } |
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| 112 | bool accept(double cost_diff) { |
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| 113 | return (drand48() <= exp(cost_diff / temp)); |
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| 114 | } |
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| 115 | }; |
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| 116 | |
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[942] | 117 | } |
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[918] | 118 | |
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| 119 | #endif |
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