def accuracy_fed_avg(self, reports):
import fl_model # pylint: disable=import-error
# Extract updates from reports
updates = self.extract_client_updates(reports)
# Extract client accuracies
accuracies = np.array([report.accuracy for report in reports])
# Determine weighting based on accuracies
factor = 8 # Exponentiation factor
w = accuracies**factor / sum(accuracies**factor)
# Perform weighted averaging
avg_update = [
torch.zeros(x.size()) # pylint: disable=no-member
for _, x in updates[0]
]
for i, update in enumerate(updates):
for j, (_, delta) in enumerate(update):
# Use weighted average by magnetude of updates
avg_update[j] += delta * w[i]
# Extract baseline model weights
baseline_weights = fl_model.extract_weights(self.model)
# Load updated weights into model
updated_weights = []
for i, (name, weight) in enumerate(baseline_weights):
updated_weights.append((name, weight + avg_update[i]))
return updated_weights
def federated_averaging(self, reports):
import fl_model # pylint: disable=import-error
# Extract updates from reports
updates = self.extract_client_updates(reports)
# Extract total number of samples
total_samples = sum([report.num_samples for report in reports])
# Perform weighted averaging
avg_update = [
torch.zeros(x.size()) # pylint: disable=no-member
for _, x in updates[0]
]
for i, update in enumerate(updates):
num_samples = reports[i].num_samples
for j, (_, delta) in enumerate(update):
# Use weighted average by number of samples
avg_update[j] += delta * (num_samples / total_samples)
# Extract baseline model weights
baseline_weights = fl_model.extract_weights(self.model)
# Load updated weights into model
updated_weights = []
for i, (name, weight) in enumerate(baseline_weights):
updated_weights.append((name, weight + avg_update[i]))
return updated_weights
def magnetude_fed_avg(self, reports):
import fl_model # pylint: disable=import-error
# Extract updates from reports
updates = self.extract_client_updates(reports)
# Extract update magnetudes
magnetudes = []
for update in updates:
magnetude = 0
for _, weight in update:
magnetude += weight.norm() ** 2
magnetudes.append(np.sqrt(magnetude))
# Perform weighted averaging
avg_update = [torch.zeros(x.size()) # pylint: disable=no-member
for _, x in updates[0]]
for i, update in enumerate(updates):
for j, (_, delta) in enumerate(update):
# Use weighted average by magnetude of updates
avg_update[j] += delta * (magnetudes[i] / sum(magnetudes))
# Extract baseline model weights
baseline_weights = fl_model.extract_weights(self.model)
# Load updated weights into model
updated_weights = []
for i, (name, weight) in enumerate(baseline_weights):
updated_weights.append((name, weight + avg_update[i]))
return updated_weights
def extract_client_updates(self, reports):
import fl_model # pylint: disable=import-error
# Extract baseline model weights
baseline_weights = fl_model.extract_weights(self.model)
# Extract weights from reports
weights = [report.weights for report in reports]
# Calculate updates from weights
updates = []
for weight in weights:
update = []
for i, (name, weight) in enumerate(weight):
bl_name, baseline = baseline_weights[i]
# Ensure correct weight is being updated
assert name == bl_name
# Calculate update
delta = weight - baseline
update.append((name, delta))
updates.append(update)
return updates
def save_reports(self, round, reports):
import fl_model # pylint: disable=import-error
if reports:
self.saved_reports['round{}'.format(round)] = [(report.client_id, self.flatten_weights(
report.weights)) for report in reports]
# Extract global weights
self.saved_reports['w{}'.format(round)] = self.flatten_weights(
fl_model.extract_weights(self.model))
def profiling(self):
import fl_model # pylint: disable=import-error
# Use all clients for profiling
clients = self.clients
# Configure clients for training
self.configuration(clients)
# Train on clients to generate profile weights
threads = [Thread(target=client.train) for client in self.clients]
[t.start() for t in threads]
[t.join() for t in threads]
# Recieve client reports
reports = self.reporting(clients)
# Extract weights from reports
weights = [report.weights for report in reports]
weights = [self.flatten_weights(weight) for weight in weights]
# Extract initial model weights
w0 = self.flatten_weights(fl_model.extract_weights(self.model))
# Save as initial previous model weights
self.w_previous = w0.copy()
# Update initial model using results of profiling
# Perform weight aggregation
logging.info('Aggregating updates')
updated_weights = self.aggregation(reports)
# Load updated weights
fl_model.load_weights(self.model, updated_weights)
# Calculate direction vectors (directors)
directors = [(w - w0) for w in weights]
# Normalize directors to unit length
directors = [d / np.sqrt(np.dot(d, d)) for d in directors]
# Initialize punishment factors
self.punishment = [0 for _ in range(len(clients))]
# Use directors for client profiles
self.profiles = [(client, directors[i])
for i, client in enumerate(clients)]
return self.profiles
def selection(self):
import fl_model # pylint: disable=import-error
clients = self.clients
clients_per_round = self.config.clients.per_round
profiles = self.profiles
w_previous = self.w_previous
# Extract directors from profiles
directors = [d for _, d in profiles]
# Extract most recent model weights
w_current = self.flatten_weights(fl_model.extract_weights(self.model))
model_direction = w_current - w_previous
# Normalize model direction
model_direction = model_direction / \
np.sqrt(np.dot(model_direction, model_direction))
# Update previous model weights
self.w_previous = w_current
# Generate client director scores (closer direction is better)
scores = [np.dot(director, model_direction) for director in directors]
# Apply punishment for repeatedly selected clients
p = self.punishment
scores = [x * (0.9)**p[i] for i, x in enumerate(scores)]
# Select clients with highest scores
sample_clients_index = []
for _ in range(clients_per_round):
top_score_index = scores.index(max(scores))
sample_clients_index.append(top_score_index)
# Overwrite to avoid reselection
scores[top_score_index] = min(scores) - 1
# Extract selected sample clients
sample_clients = [clients[i] for i in sample_clients_index]
# Update punishment factors
self.punishment = [
p[i] + 1 if i in sample_clients_index else 0
for i in range(len(clients))
]
return sample_clients
def train(self):
import fl_model # pylint: disable=import-error
logging.info('Training on client #{}'.format(self.client_id))
# Perform model training
trainloader = fl_model.get_trainloader(self.trainset, self.batch_size)
fl_model.train(self.model, trainloader, self.optimizer, self.epochs)
# Extract model weights and biases
weights = fl_model.extract_weights(self.model)
# Generate report for server
self.report = Report(self)
self.report.weights = weights
# Perform model testing if applicable
if self.do_test:
testloader = fl_model.get_testloader(self.testset, 1000)
self.report.accuracy = fl_model.test(self.model, testloader)
