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import gradio as gr
import matplotlib.pyplot as plt
import numpy as np
from sklearn import datasets
from sklearn.linear_model import LogisticRegression
from sklearn.preprocessing import StandardScaler
rng = np.random.default_rng(0)
X, y = datasets.load_digits(return_X_y=True)
X = StandardScaler().fit_transform(X)
# classify small against large digits
y = (y > 4).astype(int)
# l1_ratio = 0.5 # L1 weight in the Elastic-Net regularization
md_description = """
# L1 Penalty and Sparsity in Logistic Regression
Comparison of the sparsity (percentage of zero coefficients) of solutions when L1, L2 and Elastic-Net penalty are used for different values of C. We can see that large values of C give more freedom to the model. Conversely, smaller values of C constrain the model more. In the L1 penalty case, this leads to sparser solutions. As expected, the Elastic-Net penalty sparsity is between that of L1 and L2.
We classify 8x8 images of digits into two classes: 0-4 against 5-9. The visualization shows coefficients of the models for varying C.
"""
def make_regression(l1_ratio):
fig, axes = plt.subplots(3, 3)
# Set regularization parameter
for i, (C, axes_row) in enumerate(zip((1, 0.1, 0.01), axes)):
# Increase tolerance for short training time
clf_l1_LR = LogisticRegression(C=C, penalty="l1", tol=0.01, solver="saga")
clf_l2_LR = LogisticRegression(C=C, penalty="l2", tol=0.01, solver="saga")
clf_en_LR = LogisticRegression(
C=C, penalty="elasticnet", solver="saga", l1_ratio=l1_ratio, tol=0.01
)
clf_l1_LR.fit(X, y)
clf_l2_LR.fit(X, y)
clf_en_LR.fit(X, y)
coef_l1_LR = clf_l1_LR.coef_.ravel()
coef_l2_LR = clf_l2_LR.coef_.ravel()
coef_en_LR = clf_en_LR.coef_.ravel()
# coef_l1_LR contains zeros due to the
# L1 sparsity inducing norm
sparsity_l1_LR = np.mean(coef_l1_LR == 0) * 100
sparsity_l2_LR = np.mean(coef_l2_LR == 0) * 100
sparsity_en_LR = np.mean(coef_en_LR == 0) * 100
print(f"C={C:.2f}")
print(f"{'Sparsity with L1 penalty:':<40} {sparsity_l1_LR:2f}%")
print(f"{'Sparsity with Elastic-Net penalty:':<40} {sparsity_en_LR:.2f}%")
print(f"{'Sparsity with L2 penalty:':<40} {sparsity_l2_LR:.2f}%")
print(f"{'Score with L1 penalty:':<40} {clf_l1_LR.score(X, y):.2f}")
print(f"{'Score with Elastic-Net penalty:':<40} {clf_en_LR.score(X, y):.2f}")
print(f"{'Score with L2 penalty:':<40} {clf_l2_LR.score(X, y):.2f}")
log_out = f"""
C={C:.2f}
{'Sparsity with L1 penalty:':<40} {sparsity_l1_LR:2f}%
{'Sparsity with Elastic-Net penalty:':<40} {sparsity_en_LR:.2f}%
{'Sparsity with L2 penalty:':<40} {sparsity_l2_LR:.2f}%
{'Score with L1 penalty:':<40} {clf_l1_LR.score(X, y):.2f}
{'Score with Elastic-Net penalty:':<40} {clf_en_LR.score(X, y):.2f}
{'Score with L2 penalty:':<40} {clf_l2_LR.score(X, y):.2f}
"""
if i == 0:
axes_row[0].set_title("L1 penalty")
axes_row[1].set_title(f"Elastic-Net\nl1/l2_ratio = {l1_ratio}")
axes_row[2].set_title("L2 penalty")
for ax, coefs in zip(axes_row, [coef_l1_LR, coef_en_LR, coef_l2_LR]):
ax.imshow(
np.abs(coefs.reshape(8, 8)),
interpolation="nearest",
cmap="binary",
vmax=1,
vmin=0,
)
ax.set_xticks(())
ax.set_yticks(())
axes_row[0].set_ylabel(f"{C=}")
return fig, log_out, make_example(l1_ratio)
def make_example(l1_ratio):
return f"""
With the following code you can reproduce this example with the current values of the sliders and the same data in a notebook:
```python
import numpy as np
import matplotlib.pyplot as plt
from sklearn.linear_model import LogisticRegression
from sklearn import datasets
from sklearn.preprocessing import StandardScaler
rng = np.random.default_rng(0)
X, y = datasets.load_digits(return_X_y=True)
X = StandardScaler().fit_transform(X)
# classify small against large digits
y = (y > 4).astype(int)
l1_ratio = 0.5 # L1 weight in the Elastic-Net regularization
fig, axes = plt.subplots(3, 3)
# Set regularization parameter
for i, (C, axes_row) in enumerate(zip((1, 0.1, 0.01), axes)):
# Increase tolerance for short training time
clf_l1_LR = LogisticRegression(C=C, penalty="l1", tol=0.01, solver="saga")
clf_l2_LR = LogisticRegression(C=C, penalty="l2", tol=0.01, solver="saga")
clf_en_LR = LogisticRegression(
C=C, penalty="elasticnet", solver="saga", l1_ratio=l1_ratio, tol=0.01
)
clf_l1_LR.fit(X, y)
clf_l2_LR.fit(X, y)
clf_en_LR.fit(X, y)
coef_l1_LR = clf_l1_LR.coef_.ravel()
coef_l2_LR = clf_l2_LR.coef_.ravel()
coef_en_LR = clf_en_LR.coef_.ravel()
# coef_l1_LR contains zeros due to the
# L1 sparsity inducing norm
sparsity_l1_LR = np.mean(coef_l1_LR == 0) * 100
sparsity_l2_LR = np.mean(coef_l2_LR == 0) * 100
sparsity_en_LR = np.mean(coef_en_LR == 0) * 100
print(f"C={{C:.2f}}")
print(f"{{'Sparsity with L1 penalty:':<40}} {{sparsity_l1_LR:2f}}%\")
print(f"{{'Sparsity with Elastic-Net penalty:':<40}} {{sparsity_en_LR:.2f}}%")
print(f"{{'Sparsity with L2 penalty:':<40}} {{sparsity_l2_LR:.2f}}%")
print(f"{{'Score with L1 penalty:':<40}} {{clf_l1_LR.score(X, y):.2f}}")
print(f"{{'Score with Elastic-Net penalty:':<40}} {{clf_en_LR.score(X, y):.2f}}")
print(f"{{'Score with L2 penalty:':<40}} {{clf_l2_LR.score(X, y):.2f}}")
if i == 0:
axes_row[0].set_title("L1 penalty")
axes_row[1].set_title(f"Elastic-Net\\nl1/l2_ratio = {l1_ratio}")
axes_row[2].set_title("L2 penalty")
for ax, coefs in zip(axes_row, [coef_l1_LR, coef_en_LR, coef_l2_LR]):
ax.imshow(
np.abs(coefs.reshape(8, 8)),
interpolation="nearest",
cmap="binary",
vmax=1,
vmin=0,
)
ax.set_xticks(())
ax.set_yticks(())
axes_row[0].set_ylabel(f"{{C=}}")
plt.show()
```
"""
with gr.Blocks() as demo:
with gr.Row():
gr.Markdown(md_description)
with gr.Row():
with gr.Column():
ratio_slider = gr.Slider(minimum=0, maximum=1, label="L1/L2 ratio", step=0.1, value=0.5)
button = gr.Button(value="Generate")
with gr.Column():
plot = gr.Plot(label="Output")
log = gr.Markdown("", label="Log")
with gr.Row():
example = gr.Markdown(make_example(ratio_slider.value))
button.click(make_regression, inputs=[ratio_slider], outputs=[plot, log, example])
ratio_slider.change(fn=make_regression, inputs=[ratio_slider], outputs=[plot, log, example])
demo.launch()