Added an example that uses the OpenAI Gym's LunarLander-v2 environment.

Author: CodeReclaimers

examples/openai-lander/config

@@ -0,0 +1,62 @@
+# neat-python configuration for the LunarLander-v2 environment on OpenAI Gym
+
+[NEAT]
+pop_size              = 200
+max_fitness_threshold = 1000.0
+reset_on_extinction   = 0
+
+[DefaultGenome]
+num_inputs              = 8
+num_hidden              = 0
+num_outputs             = 4
+initial_connection      = full
+feed_forward            = True
+compatibility_disjoint_coefficient = 1.0
+compatibility_weight_coefficient   = 1.0
+conn_add_prob           = 0.15
+conn_delete_prob        = 0.1
+node_add_prob           = 0.15
+node_delete_prob        = 0.1
+activation_default      = tanh
+activation_options      = tanh clamped gauss hat sin
+activation_mutate_rate  = 0.05
+aggregation_default     = sum
+aggregation_options     = sum
+aggregation_mutate_rate = 0.0
+bias_init_mean          = 0.0
+bias_init_stdev         = 1.0
+bias_replace_rate       = 0.02
+bias_mutate_rate        = 0.8
+bias_mutate_power       = 0.4
+bias_max_value          = 30.0
+bias_min_value          = -30.0
+response_init_mean      = 1.0
+response_init_stdev     = 0.0
+response_replace_rate   = 0.0
+response_mutate_rate    = 0.1
+response_mutate_power   = 0.01
+response_max_value      = 30.0
+response_min_value      = -30.0
+
+weight_max_value        = 30
+weight_min_value        = -30
+weight_init_mean        = 0.0
+weight_init_stdev       = 1.0
+weight_mutate_rate      = 0.8
+weight_replace_rate     = 0.02
+weight_mutate_power     = 0.4
+enabled_default         = True
+enabled_mutate_rate     = 0.01
+
+[DefaultSpeciesSet]
+compatibility_threshold = 3.0
+
+[DefaultStagnation]
+species_fitness_func = mean
+max_stagnation       = 15
+species_elitism      = 5
+
+[DefaultReproduction]
+elitism            = 2
+survival_threshold = 0.2
+

examples/openai-lander/evolve.py

@@ -0,0 +1,185 @@
+# Evolve a control/reward estimation network for the OpenAI Gym
+# LunarLander-v2 environment (https://gym.openai.com/envs/LunarLander-v2).
+# This is a work in progress, and currently takes ~100 generations to
+# find a network that can land with a score >= 200 at least a couple of
+# times.  It has yet to solve the environment, which could have something
+# to do to me being totally clueless in regard to reinforcement learning. :)
+
+from __future__ import print_function
+
+import gym
+import gym.wrappers
+
+import matplotlib.pyplot as plt
+
+import neat
+import numpy as np
+import os
+import pickle
+import random
+
+import visualize
+
+env = gym.make('LunarLander-v2')
+
+print("action space: {0!r}".format(env.action_space))
+print("observation space: {0!r}".format(env.observation_space))
+
+# Limit episodes to 400 time steps to cut down on training time.
+# 400 steps is more than enough time to land with a winning score.
+print(env.spec.tags.get('wrapper_config.TimeLimit.max_episode_steps'))
+env.spec.tags['wrapper_config.TimeLimit.max_episode_steps'] = 400
+print(env.spec.tags.get('wrapper_config.TimeLimit.max_episode_steps'))
+
+env = gym.wrappers.Monitor(env, 'results', force=True)
+
+discounted_reward = 0.9
+min_reward = -200
+max_reward = 200
+
+score_range = []
+
+def eval_fitness_shared(genomes, config):
+    nets = []
+    for gid, g in genomes:
+        nets.append((g, neat.nn.FeedForwardNetwork.create(g, config)))
+        g.fitness = []
+
+    episodes = []
+    scores = []
+    for genome, net in nets:
+        observation = env.reset()
+        episode_data = []
+        j = 0
+        total_score = 0.0
+        while 1:
+            if net is not None:
+                output = net.activate(observation)
+                action = np.argmax(output)
+            else:
+                action = env.action_space.sample()
+
+            observation, reward, done, info = env.step(action)
+            total_score += reward
+            episode_data.append((j, observation, action, reward))
+
+            if done:
+                break
+
+            j += 1
+
+        episodes.append(episode_data)
+        scores.append(total_score)
+        genome.fitness = total_score
+
+    if scores:
+        score_range.append((min(scores), np.mean(scores), max(scores)))
+
+    # Compute discounted rewards.
+    discounted_rewards = []
+    for episode in episodes:
+        rewards = np.array([reward for j, observation, action, reward in episode])
+        N = len(episode)
+        D = np.sum((np.eye(N, k=i) * discounted_reward ** i for i in range(N)))
+        discounted_rewards.append(np.dot(D, rewards))
+
+    print(min(map(np.min, discounted_rewards)), max(map(np.max, discounted_rewards)))
+
+    # Normalize rewards
+    for i in range(len(discounted_rewards)):
+        discounted_rewards[i] = 2 * (discounted_rewards[i] - min_reward) / (max_reward - min_reward) - 1.0
+
+    print(min(map(np.min, discounted_rewards)), max(map(np.max, discounted_rewards)))
+
+    episode_filter = [random.randint(0, len(episodes)-1) for _ in range(10)]
+    for genome, net in nets:
+        reward_error = []
+        for i in episode_filter:
+            episode = episodes[i]
+            discount_reward = discounted_rewards[i]
+            for (j, observation, action, reward), dr in zip(episode, discount_reward):
+                #test_set.append((observation, action, reward, dr))
+                output = net.activate(observation)
+                reward_error.append((output[action] - dr)**2)
+
+        print(genome.fitness, np.mean(reward_error))
+        genome.fitness -= 100 * np.mean(reward_error)
+
+
+def run():
+    # Load the config file, which is assumed to live in
+    # the same directory as this script.
+    local_dir = os.path.dirname(__file__)
+    config_path = os.path.join(local_dir, 'config')
+    config = neat.Config(neat.DefaultGenome, neat.DefaultReproduction,
+                         neat.DefaultSpeciesSet, neat.DefaultStagnation,
+                         config_path)
+
+    pop = neat.Population(config)
+    stats = neat.StatisticsReporter()
+    pop.add_reporter(stats)
+    pop.add_reporter(neat.StdOutReporter())
+    # Checkpoint every 10 generations or 900 seconds.
+    pop.add_reporter(neat.Checkpointer(10, 900))
+
+    # Run until the winner from a generation is able to solve the environment.
+    while 1:
+        winner = pop.run(eval_fitness_shared, 1)
+
+        visualize.plot_stats(stats, ylog=False, view=False, filename="fitness.svg")
+
+        if score_range:
+            S = np.array(score_range).T
+            plt.plot(S[0], 'r-')
+            plt.plot(S[1], 'b-')
+            plt.plot(S[2], 'g-')
+            plt.grid()
+            plt.savefig("score-ranges.svg")
+            plt.close()
+
+        mfs = sum(stats.get_fitness_mean()[-5:]) / 5.0
+        print("Average mean fitness over last 5 generations: {0}".format(mfs))
+
+        mfs = sum(stats.get_fitness_stat(min)[-5:]) / 5.0
+        print("Average min fitness over last 5 generations: {0}".format(mfs))
+
+        winner_net = neat.nn.FeedForwardNetwork.create(winner, config)
+
+        for k in range(100):
+            observation = env.reset()
+            score = 0
+            while 1:
+                output = winner_net.activate(observation)
+                observation, reward, done, info = env.step(np.argmax(output))
+                score += reward
+                env.render()
+                if done:
+                    break
+            print(k, score)
+            if score < 200:
+                break
+        else:
+            print("Solved.")
+            break
+
+    winner = stats.best_genome()
+    print(winner)
+
+    # Save the winner.
+    with open('winner.pickle', 'wb') as f:
+        pickle.dump(winner, f)
+
+    visualize.plot_stats(stats, ylog=False, view=True, filename="fitness.svg")
+    visualize.plot_species(stats, view=True, filename="speciation.svg")
+
+    visualize.draw_net(config, winner, True)
+
+    visualize.draw_net(config, winner, view=True, filename="winner-net.gv")
+    visualize.draw_net(config, winner, view=True, filename="winner-net-enabled.gv",
+                       show_disabled=False)
+    visualize.draw_net(config, winner, view=True, filename="winner-net-enabled-pruned.gv",
+                       show_disabled=False, prune_unused=True)
+
+
+if __name__ == '__main__':
+    run()