September 2, 2024
Gradient Echo: Pioneering the Future of Deep Learning
Copy and paste the text into a new notebook in Google Colab, then run the code.
!pip install torch norse import gym import torch import torch.nn as nn import torch.optim as optim import numpy as np import norse.torch as norse # Gradient Echo Layer class GradientEchoLayer(nn.Module): def __init__(self, input_size, output_size, echo_factor=0.9, memory_size=5): super(GradientEchoLayer, self).__init__() self.fc = nn.Linear(input_size, output_size) self.echo_factor = echo_factor self.memory_size = memory_size self.gradient_memory = [] def forward(self, x): return torch.relu(self.fc(x)) def modify_grad(self, grad): if len(self.gradient_memory) > 0 and grad.shape != self.gradient_memory[0].shape: self.gradient_memory = [] if len(self.gradient_memory) >= self.memory_size: self.gradient_memory.pop(0) self.gradient_memory.append(grad.clone().detach()) echo_grad = torch.zeros_like(grad) for i, past_grad in enumerate(reversed(self.gradient_memory)): echo_grad += self.echo_factor ** i * past_grad return grad + echo_grad def register_hooks(self): self.fc.weight.register_hook(self.modify_grad) self.fc.bias.register_hook(self.modify_grad) # Policy Network with Gradient Echo class PolicyNetwork(nn.Module): def __init__(self, input_size, hidden_size, output_size): super(PolicyNetwork, self).__init__() self.layer1 = GradientEchoLayer(input_size, hidden_size) self.fc2 = nn.Linear(hidden_size, hidden_size) self.fc3 = nn.Linear(hidden_size, output_size) self.layer1.register_hooks() def forward(self, x): x = self.layer1(x) x = torch.relu(self.fc2(x)) return torch.softmax(self.fc3(x), dim=-1) # Liquid State Machine (LSM) for reward processing class LiquidStateLayer(nn.Module): def __init__(self, input_size, hidden_size): super(LiquidStateLayer, self).__init__() self.lif = norse.LIFCell() # Leaky Integrate-and-Fire neuron model self.fc = nn.Linear(input_size, hidden_size) def forward(self, x, state=None): x = self.fc(x) out, state = self.lif(x, state) return out, state # Surrogate Model with LSM and Gradient Echo for reward prediction class SurrogateModelWithLSM(nn.Module): def __init__(self, input_size, liquid_hidden_size, hidden_size): super(SurrogateModelWithLSM, self).__init__() self.liquid_state_layer = LiquidStateLayer(input_size, liquid_hidden_size) self.gradient_echo_layer = GradientEchoLayer(liquid_hidden_size, hidden_size) self.fc2 = nn.Linear(hidden_size, 1) self.gradient_echo_layer.register_hooks() def forward(self, x, symbolic_output): state = None # Initialize state for LIF neurons liquid_out, state = self.liquid_state_layer(x, state) x = torch.relu(self.gradient_echo_layer(liquid_out)) # Reward adjustment based on symbolic reasoning reward = self.fc2(x) if symbolic_output['risk'] == "freeze": reward -= 1 elif symbolic_output['risk'] == "dry_out": reward -= 0.5 return reward # Simple Neural Network for symbolic reasoning class SimpleNN(nn.Module): def __init__(self): super(SimpleNN, self).__init__() self.fc1 = nn.Linear(10, 64) self.fc2 = nn.Linear(64, 32) self.fc3 = nn.Linear(32, 2) def forward(self, x): x = torch.relu(self.fc1(x)) x = torch.relu(self.fc2(x)) return torch.sigmoid(self.fc3(x)) # Output between 0 and 1 for binary decision # Symbolic reasoning based on environmental factors def symbolic_reasoning(rain, sprinkler, temperature): wet = rain or sprinkler if temperature < 0: risk = "freeze" elif temperature > 30: risk = "dry_out" else: risk = "normal" return {"wet": wet, "risk": risk} # Decision making based on neural and symbolic outputs def hybrid_decision_making(nn_output, symbolic_output): nn_output = nn_output.squeeze() if symbolic_output['risk'] == "freeze" and nn_output[0] > nn_output[1]: return "Action A" elif symbolic_output['risk'] == "dry_out" and nn_output[1] > nn_output[0]: return "Action B" return "Action B" if symbolic_output['wet'] else "Action A" # Action selection function def select_action(state, symbolic_output, surrogate_model): state_tensor = torch.tensor(state, dtype=torch.float32) action_probs = policy_net(state_tensor) action = torch.multinomial(action_probs, 1).item() log_prob = torch.log(action_probs[action]) symbolic_decision = hybrid_decision_making(action_probs, symbolic_output) predicted_reward = surrogate_model(state_tensor, symbolic_output) return action, log_prob, symbolic_decision, predicted_reward # Meta-learning update function def meta_learning_update(policy_net, optimizer, rewards, log_probs, surrogate_model, surrogate_optimizer, states, symbolic_outputs, discount_factor=0.99): discounted_rewards = [] for t in range(len(rewards)): Gt = sum([r * (discount_factor ** i) for i, r in enumerate(rewards[t:])]) discounted_rewards.append(Gt) discounted_rewards = torch.tensor(discounted_rewards) discounted_rewards = (discounted_rewards - discounted_rewards.mean()) / (discounted_rewards.std() + 1e-9) # Normalize rewards loss = -sum([log_prob * Gt for log_prob, Gt in zip(log_probs, discounted_rewards)]) optimizer.zero_grad() loss.backward() torch.nn.utils.clip_grad_norm_(policy_net.parameters(), 1.0) # Gradient clipping optimizer.step() # Update the surrogate model using the true rewards and states surrogate_optimizer.zero_grad() surrogate_loss = 0 for state, symbolic_output, Gt in zip(states, symbolic_outputs, discounted_rewards): surrogate_loss += ((surrogate_model(state, symbolic_output) - Gt) ** 2).mean() surrogate_loss.backward() surrogate_optimizer.step() # Set up the environment using the new step API env = gym.make('CartPole-v1', new_step_api=True) # Initialize Policy Network and Surrogate Model with LSM for reward prediction policy_net = PolicyNetwork(input_size=env.observation_space.shape[0], hidden_size=128, output_size=env.action_space.n) surrogate_model = SurrogateModelWithLSM(input_size=env.observation_space.shape[0], liquid_hidden_size=128, hidden_size=128) # Initialize the Simple Neural Network for symbolic reasoning simple_nn = SimpleNN() optimizer = optim.Adam(policy_net.parameters(), lr=0.001) surrogate_optimizer = optim.Adam(surrogate_model.parameters(), lr=0.001) # Run the training loop num_episodes = 3000 for episode in range(num_episodes): state = env.reset() done = False rewards = [] log_probs = [] states = [] symbolic_outputs = [] while not done: # Generate random input for the symbolic NN symbolic_input = torch.randn(1, 10) symbolic_nn_output = simple_nn(symbolic_input) temperature = np.random.uniform(-5, 40) # Random temperature input symbolic_output = symbolic_reasoning(rain=True, sprinkler=False, temperature=temperature) action, log_prob, symbolic_decision, predicted_reward = select_action(state, symbolic_output, surrogate_model) state, reward, done, truncated, _ = env.step(action) rewards.append(reward) log_probs.append(log_prob) states.append(torch.tensor(state, dtype=torch.float32)) symbolic_outputs.append(symbolic_output) if done or truncated: meta_learning_update(policy_net, optimizer, rewards, log_probs, surrogate_model, surrogate_optimizer, torch.stack(states), symbolic_outputs) total_reward = sum(rewards) if episode % 100 == 0: print(f"Episode {episode}, Total Reward: {total_reward}, Symbolic Decision: {symbolic_decision}") break env.close() # Copyright 2024 square play # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # http://www.apache.org/licenses/LICENSE-2.0 # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License.