Updated the code.

This commit is contained in:
Batuhan Berk Başoğlu 2025-10-20 17:45:59 +03:00
parent 5cc1604996
commit 970eb334df
14 changed files with 72 additions and 74 deletions

2
.idea/misc.xml generated
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@ -3,5 +3,5 @@
<component name="Black"> <component name="Black">
<option name="sdkName" value="Python 3.14 (-Comp-551-Assignment-2)" /> <option name="sdkName" value="Python 3.14 (-Comp-551-Assignment-2)" />
</component> </component>
<component name="ProjectRootManager" version="2" project-jdk-name="Python 3.14 (-Comp-551-Assignment-2)" project-jdk-type="Python SDK" /> <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.14" project-jdk-type="Python SDK" />
</project> </project>

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@ -1,72 +0,0 @@
import numpy as np
import matplotlib.pyplot as plt
# Generating Synthetic Data
def generate_linear_data(n):
x = np.random.uniform(0, 10, n) # initialize x
eps = np.random.normal(0, 1, n) # initialize epsilon
y = -3 * x + 8 + 2 * eps # y = 3x + 8 + 2ϵ
return x.reshape(-1, 1), y
# Gradient Descent with L1/L2
def gradient_descent(x, y, lam, reg_type, lr, iters):
x_b = np.hstack([np.ones_like(x), x]) # initialize x
w = np.zeros(x_b.shape[1]) # initialize weight
path = [w.copy()]
for i in range(iters):
pred = x_b @ w # linear regression prediction
error = pred - y # error
grad = x_b.T @ error / len(y) # gradient formula
if reg_type == 'l2':
grad += lam * w # L2 formula
elif reg_type == 'l1':
grad += lam * np.sign(w) # L1 formula
w -= lr * grad # loss calculation
path.append(w.copy())
return w, np.array(path)
# Plotting the loss
def plot_contour(x, y, reg_type, lam):
x_b = np.hstack([np.ones_like(x), x]) # initialize x
w0, w1 = np.meshgrid(np.linspace(-10, 10, 100), np.linspace(-10, 10, 100)) # initialize intercept and slope
loss = np.zeros_like(w0) # initialize loss
for i in range(w0.shape[0]):
for j in range(w0.shape[1]):
w = np.array([w0[i, j], w1[i, j]])
error = y - x_b @ w # error
mse = np.mean(error ** 2) # mean square error
reg = lam * (np.sum(w ** 2) if reg_type == 'l2' else np.sum(np.abs(w))) # regularization
loss[i, j] = mse + reg # regularization and mse for the loss
_, path = gradient_descent(x, y, lam, reg_type, 0.01, 500)
# plotting the figure
plt.figure(figsize=(6, 5))
plt.contour(w0, w1, loss, levels=50, cmap='viridis')
plt.plot(path[:, 0], path[:, 1], 'ro-', markersize=2, label='Gradient Descent Path')
plt.title(f"{reg_type.upper()} Regularization (λ={lam})")
plt.xlabel("w0 (intercept)")
plt.ylabel("w1 (slope)")
plt.grid(True)
plt.legend()
plt.tight_layout()
plt.savefig('results/task4-effect-of-regularization-on-loss-' + reg_type + '-' + str(lam) + '.png')
if __name__ == "__main__":
print("Running Task 4: Effect of L1 and L2 Regularization on Loss Landscape")
# Generate dataset
x, y = generate_linear_data(30)
# Values of lambda to visualize
lambda_values = [0.01, 0.1, 1.0]
# Plot for both L1 and L2 regularization
for reg_type in ['l1', 'l2']:
for lam in lambda_values:
plot_contour(x, y, reg_type, lam)

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@ -137,6 +137,63 @@ def bias_variance_decomp(reg_type, lam_values, num_datasets, N, D):
plt.grid(True) plt.grid(True)
plt.savefig('results/task3-bias-decomposition-' + reg_type + '.png') plt.savefig('results/task3-bias-decomposition-' + reg_type + '.png')
# Generating Synthetic Data
def generate_linear_data(n):
x = np.random.uniform(0, 10, n) # initialize x
eps = np.random.normal(0, 1, n) # initialize epsilon
y = -3 * x + 8 + 2 * eps # y = 3x + 8 + 2ϵ
return x.reshape(-1, 1), y
# Gradient Descent with L1/L2
def gradient_descent(x, y, lam, reg_type, lr, iters):
x_b = np.hstack([np.ones_like(x), x]) # initialize x
w = np.zeros(x_b.shape[1]) # initialize weight
path = [w.copy()]
for i in range(iters):
pred = x_b @ w # linear regression prediction
error = pred - y # error
grad = x_b.T @ error / len(y) # gradient formula
if reg_type == 'l2':
grad += lam * w # L2 formula
elif reg_type == 'l1':
grad += lam * np.sign(w) # L1 formula
w -= lr * grad # loss calculation
path.append(w.copy())
return w, np.array(path)
# Plotting the loss
def plot_contour(x, y, reg_type, lam):
x_b = np.hstack([np.ones_like(x), x]) # initialize x
w0, w1 = np.meshgrid(np.linspace(-10, 10, 100), np.linspace(-10, 10, 100)) # initialize intercept and slope
loss = np.zeros_like(w0) # initialize loss
for i in range(w0.shape[0]):
for j in range(w0.shape[1]):
w = np.array([w0[i, j], w1[i, j]])
error = y - x_b @ w # error
mse = np.mean(error ** 2) # mean square error
reg = lam * (np.sum(w ** 2) if reg_type == 'l2' else np.sum(np.abs(w))) # regularization
loss[i, j] = mse + reg # regularization and mse for the loss
_, path = gradient_descent(x, y, lam, reg_type, 0.01, 500)
# plotting the figure
plt.figure(figsize=(6, 5))
plt.contour(w0, w1, loss, levels=50, cmap='viridis')
plt.plot(path[:, 0], path[:, 1], 'ro-', markersize=2, label='Gradient Descent Path')
plt.title(f"{reg_type.upper()} Regularization (λ={lam})")
plt.xlabel("w0 (intercept)")
plt.ylabel("w1 (slope)")
plt.grid(True)
plt.legend()
plt.tight_layout()
plt.savefig('results/task4-effect-of-regularization-on-loss-' + reg_type + '-' + str(lam) + '.png')
if __name__ == "__main__": if __name__ == "__main__":
print("Running Task 3: Regularization with Cross-Validation") print("Running Task 3: Regularization with Cross-Validation")
@ -146,4 +203,17 @@ if __name__ == "__main__":
train_validation_err('l1', lam_values, 50, 20, 45) train_validation_err('l1', lam_values, 50, 20, 45)
bias_variance_decomp('l2', lam_values, 50, 20, 45) bias_variance_decomp('l2', lam_values, 50, 20, 45)
bias_variance_decomp('l1', lam_values, 50, 20, 45) bias_variance_decomp('l1', lam_values, 50, 20, 45)
print("Running Task 4: Effect of L1 and L2 Regularization on Loss Landscape")
# Generate dataset
x, y = generate_linear_data(30)
# Values of lambda to visualize
lambda_values = [0.01, 0.1, 1.0]
# Plot for both L1 and L2 regularization
for reg_type in ['l1', 'l2']:
for lam in lambda_values:
plot_contour(x, y, reg_type, lam)