Deap贪吃蛇AI算法

Genetic programming is a special field of evolutionary computation that aims at building programs automatically to solve problems independently of their domain. In our game, the evolved individuals can be used to control the snake so that it can eat all the food located in a given environment.

Primitives

pset.addPrimitive(snk.if_food_ahead, 2)
pset.addPrimitive(snk.if_wall_tail_ahead, 2)
pset.addPrimitive(snk.if_direction_food, 2)
pset.addPrimitive(prog2, 2)
pset.addPrimitive(prog3, 3)

pset.addTerminal(snk.update_snake_position)
pset.addTerminal(snk.turn_left)
pset.addTerminal(snk.turn_right)

• if_food_ahead is a primitive which executes its first argument if there is food in front of the snake; else, it executes its second argument.
• if_wall_tail_aheadis a primitive which executes its first argument if there is wall of tail in front of the snake; else, it executes its second argument.
• if_direction_foodis a primitive which executes its first argument if the current direction is towards the food; else, it executes its second argument. Use Manhattan Distance to evaluate the distance.
• prog2() prog3() They execute one of their children in random.
• update_snake_position makes the snake move one front. This is a terminal.
• turn_right() and turn_left() makes the snake turning clockwise and counter-clockwise, without changing its position. Those are also terminals.

Crossover

deap.tools.cxOnePoint(ind1, ind2) to crossover, which executes a one point crossover on the input individuals. The two individuals are modified in place. The resulting individuals will respectively have the length of the other.

Mutation

deap.tools.mutUniformInt

Mutate an individual by replacing attributes, with probability indpb, by a integer uniformly drawn between low and up inclusively.

Selection

deap.tools.selTournament

Select the best individual among tournsize randomly chosen individuals, k times. The list returned contains references to the input individuals.

Avoid circling

set the step_num in Class snake, if step_num bigger than self.XSIZE * self.YSIZE * 20 without a score change, let game over.

Training data

gen nevals avg std min max
0 300 0.106667 0.543405 0 6
1 193 0.296667 0.780164 0 6
2 204 0.71 1.40922 0 13
3 214 1.46667 2.3041 0 20
4 201 2.86667 3.91691 0 21
5 195 5.07 5.34276 0 21
6 196 6.67 6.59705 0 21
7 204 7.72 7.52119 0 24
8 192 9.18 8.36865 0 24
9 204 9.71333 8.66282 0 26
10 209 10.07 9.07001 0 26
11 212 11.1233 9.86922 0 44
12 198 13.6333 10.3617 0 44
13 209 15.37 11.3739 0 44
14 191 17.3833 12.4904 0 44
15 197 17.5267 13.8025 0 44
16 183 18.59 15.2522 0 44
17 205 18.0033 15.5352 0 44
18 187 19.5667 16.4193 0 44
19 200 18.64 17.0821 0 44
20 195 20.7867 17.7877 0 44
21 209 18.8 17.812 0 44
22 216 17.5533 17.2322 0 44
23 210 16.6967 17.1407 0 44
24 188 19.6933 18.3126 0 44
25 179 21.54 18.8675 0 44
26 195 20.92 17.954 0 44
27 190 20.6467 18.283 0 44
28 206 18.72 17.9065 0 46
29 200 19.4167 17.7579 0 46
30 192 20.5367 18.1726 0 46
31 198 19.7167 18.3157 0 46
32 177 22.5367 18.2741 0 46
33 195 19.7133 18.4267 0 46
34 210 17.9967 18.5746 0 46
35 190 20.6433 18.9542 0 46
36 197 20.7 18.841 0 46
37 200 20.45 18.699 0 46
38 189 21.1033 19.5016 0 46
39 202 20.8467 18.8477 0 47
40 205 19.98 18.5901 0 47
41 187 20.9467 19.3545 0 46
42 195 20.8733 19.1951 0 46
43 207 19.4767 18.8435 0 46
44 190 20.3367 19.5977 0 46
45 202 20.1367 18.9023 0 46
46 198 20.13 19.2913 0 46
47 196 20.25 19.0937 0 46
48 204 19.4233 18.4045 0 46
49 187 22.5 18.6484 0 46
50 198 20.7 18.8748 0 46
51 199 19.34 19.1779 0 46
52 196 20.0833 19.3264 0 46
53 197 20.55 19.0811 0 46
54 189 21.1933 18.9583 0 46
55 205 20.2633 18.6789 0 46
56 190 20.8167 19.1169 0 50
57 193 20.39 19.3402 0 50
58 206 19.32 18.8644 0 46
59 191 21.23 18.6797 0 46
60 213 18.45 18.1984 0 46
61 201 19.2467 18.8974 0 46
62 197 20.7333 18.98 0 46
63 206 19.9767 18.5507 0 46
64 196 20.6333 18.8948 0 46
65 187 21.56 19.1221 0 46
66 197 21.1967 18.945 0 46
67 192 21.03 19.5827 0 46
68 206 19.8933 18.7919 0 46
69 181 22.8333 19.1476 0 46
70 200 21.18 18.8962 0 46
71 191 21.4667 19.1441 0 46
72 213 18.28 18.4543 0 46
73 191 21.6833 19.0609 0 46
74 196 21.3033 19.0807 0 46
75 188 20.9933 19.5173 0 46
76 202 19.8267 18.9178 0 46
77 195 21.0167 19.191 0 46
78 186 22.8233 19.3175 0 46
79 196 20.66 19.2696 0 46
80 208 18.84 18.604 0 46
81 186 21.6867 19.1132 0 46
82 184 21.8933 19.3272 0 46
83 188 21.6667 19.2243 0 46
84 209 19.09 18.9597 0 46
85 197 20.3 18.9658 0 46
86 186 21.15 19.3985 0 46
87 188 21.53 19.6668 0 46
88 197 20.58 19.1375 0 46
89 198 20.9467 18.79 0 50
90 193 20.52 19.166 0 50
91 189 22.3767 18.9042 0 50
92 218 18.53 18.4066 0 50
93 190 20.38 19.722 0 50
94 204 20.39 19.19 0 50
95 202 21.3533 19.7341 0 50
96 191 23.0767 20.6734 0 56
97 206 22.0867 20.2206 0 56
98 211 21.3633 19.6818 0 56
99 184 24.77 20.5718 0 56
100 198 23.7333 21.6531 0 56
101 205 24.4433 20.9728 0 56
102 191 26.9767 21.7898 0 56
103 177 29.41 22.6582 0 56
104 184 29.0733 22.5553 0 56
105 192 28.16 22.2813 0 56
106 186 29.3133 21.9548 0 56
107 203 26.42 21.0438 0 56
108 181 28.96 22.4947 0 56
109 192 28.5333 21.7176 0 56
110 204 25.8033 21.7638 0 56
111 194 27.3167 21.2557 0 56
112 189 28.4933 21.781 0 56
113 198 26.7533 21.5634 0 56
114 193 27.4467 21.6157 0 56
115 187 27.9667 21.5702 0 56
116 183 30.0567 21.9019 0 56
117 199 26.4033 22.2961 0 56
118 186 28.4333 22.1094 0 56
119 200 27.1467 21.5889 0 56
120 194 28.8333 21.1496 0 56
121 197 27.31 21.654 0 56
122 197 27.33 21.6809 0 56
123 190 27.6 22.1581 0 56
124 190 28.6 21.8716 0 56
125 187 28.47 21.8656 0 56
126 200 26.9433 21.8368 0 56
127 188 27.5033 22.3733 0 56
128 207 26.4567 21.3206 0 56
129 173 30.6533 22.0094 0 56
130 192 28.0367 21.7207 0 56

How to improve

It can be seen that the snake has penetrated into its own body and the next improvement is to add new senses so that snakes can avoid it.

The method of avoiding snake circular motion is too simple, and it would be better if the snake could make its own judgment of being trapped in the loop through perception.

The method of avoiding snake circular motion is too simple, and it would be better if the snake could make its own judgment of being trapped in the loop through perception.

snk = snake(XSIZE, YSIZE)
random.seed(13)
POP_SIZE = 300
CXPB = 0.5  # CROSSOVER RATE
MUPB = 0.3  # MUTATION RATE
N_GEN = 130  # ITERATION NUMBER

# (Genetic Programming)
pset = gp.PrimitiveSet("MAIN", 0)
pset.addPrimitive(snk.if_food_ahead, 2)
pset.addPrimitive(snk.if_wall_tail_ahead, 2)
pset.addPrimitive(snk.if_direction_food, 2)
pset.addPrimitive(prog2, 2)
pset.addPrimitive(prog3, 3)

pset.addTerminal(snk.update_snake_position)
pset.addTerminal(snk.turn_left)
pset.addTerminal(snk.turn_right)

creator.create("FitnessMax", base.Fitness, weights=(1.0,))
creator.create("Individual", gp.PrimitiveTree, fitness=creator.FitnessMax)

toolbox = base.Toolbox()

# Attribute generator
toolbox.register("expr_init", gp.genFull, pset=pset, min_=1, max_=2)

# Structure initializers
toolbox.register("individual", tools.initIterate, creator.Individual, toolbox.expr_init)
toolbox.register("population", tools.initRepeat, list, toolbox.individual)
toolbox.register("evaluate", evalSnk)
toolbox.register("select", tools.selTournament, tournsize=7)
toolbox.register("mate", gp.cxOnePoint)
toolbox.register("expr_mut", gp.genFull, min_=0, max_=2)
toolbox.register("mutate", gp.mutUniform, expr=toolbox.expr_mut, pset=pset)


pop = toolbox.population(n=POP_SIZE)
hof = tools.HallOfFame(1)

stats = tools.Statistics(lambda ind: ind.fitness.values)
stats.register("avg", numpy.mean)
stats.register("std", numpy.std)
stats.register("min", numpy.min)
stats.register("max", numpy.max)