app.py

import numpy as np
import plotly.graph_objects as go

from sklearn.preprocessing import StandardScaler
from sklearn.datasets import make_moons, make_circles, make_classification, make_blobs
from sklearn.neural_network import MLPClassifier

import gradio as gr

# =========================================================================

GRANULARITY = 0.2
MARGIN = 0.5
N_SAMPLES = 150
SEED = 1

datasets = {}
X, y = make_moons(n_samples=N_SAMPLES, noise=0.2, random_state=SEED)
X = StandardScaler().fit_transform(X)
datasets["Moons"] = (X.copy(), y.copy())

X, y = make_circles(n_samples=N_SAMPLES, noise=0.2, factor=0.5, random_state=SEED)
X = StandardScaler().fit_transform(X)
datasets["Circles"] = (X.copy(), y.copy())

X, y = make_blobs(n_samples=N_SAMPLES, n_features=2, centers=4, cluster_std=2, random_state=SEED)
X = StandardScaler().fit_transform(X)
y[y==2] = 0
y[y==3] = 1
datasets["Blobs"] = (X.copy(), y.copy())

X, y =  make_classification(n_samples=N_SAMPLES, n_features=2, n_redundant=0, n_informative=2, n_clusters_per_class=1, random_state=SEED)
X += 2 * np.random.uniform(size=X.shape)
X = StandardScaler().fit_transform(X)
datasets["Linear"] = (X.copy(), y.copy())

# =========================================================================

def get_figure_dict():
    figure_dict = dict(data=[], layout={}, frames=[])

    play_button = dict(args=[None, {"mode": "immediate", "fromcurrent": False, "frame": {"duration": 50}, "transition": {"duration": 50}}],
                   label="Play",
                   method="animate")

    pause_button = dict(args=[[None], {"mode": "immediate"}],
                    label="Stop",
                    method="animate")

    slider = dict(steps=[], active=0, currentvalue={"prefix": "Iteration: "})

    figure_dict["layout"] = dict(width=600, height=600, hovermode=False, margin=dict(l=40, r=40, t=40, b=40), 
                                      title=dict(text="Decision Surface", x=0.5),
                                      sliders=[slider],
                                      updatemenus=[dict(buttons=[play_button, pause_button], direction="left", pad={"t": 85}, type="buttons", x=0.6, y=-0.05)]
                                      )

    return figure_dict

def get_decision_surface(X, model):
    x_min, x_max = X[:, 0].min() - MARGIN, X[:, 0].max() + MARGIN
    y_min, y_max = X[:, 1].min() - MARGIN, X[:, 1].max() + MARGIN
    xrange = np.arange(x_min, x_max, GRANULARITY)
    yrange = np.arange(y_min, y_max, GRANULARITY)
    x, y = np.meshgrid(xrange, yrange)
    x = x.ravel(); y = y.ravel()
    z = model.predict_proba(np.column_stack([x, y]))[:, 1]
    return x, y, z
# =========================================================================

def create_plot(dataset, alpha, h1, h2, seed):
    X, y = datasets[dataset]

    model = MLPClassifier(alpha=alpha, max_iter=2000, learning_rate_init=0.01, hidden_layer_sizes=[h1, h2], random_state=seed)

    figure_dict = get_figure_dict()

    model.partial_fit(X, y, classes=[0, 1])
    xx, yy, zz = get_decision_surface(X, model)
    figure_dict["data"] = [go.Contour(x=xx, y=yy, z=zz, opacity=0.6, showscale=False,),
                        go.Scatter(x=X[:, 0], y=X[:, 1], mode="markers", marker_color=y, marker={"colorscale": "jet", "size": 8})]

    prev_loss = np.inf
    tol = 3e-4
    for i in range(100):
        for _ in range(3):
            model.partial_fit(X, y, classes=[0, 1])
        
        if prev_loss - model.loss_ <= tol: break
        prev_loss = model.loss_
        
        xx, yy, zz = get_decision_surface(X, model)
        figure_dict["frames"].append({"data": [go.Contour(x=xx, y=yy, z=zz, opacity=0.6, showscale=False)], "name": i})

        slider_step = {"args": [[i], {"mode": "immediate"}], "method": "animate", "label": i}
        figure_dict["layout"]["sliders"][0]["steps"].append(slider_step)

    fig = go.Figure(figure_dict)
    return fig

info = '''
# Effect of Regularization Parameter of Multilayer Perceptron

This example demonstrates the effect of varying the regularization parameter (alpha) of a multilayer perceptron on the binary classification of toy datasets, as represented by the decision surface of the classifier.

Higher values of alpha encourages smaller weights, thus making the model less prone to overfitting, while lower values may help against underfitting. Use the slider below to control the amount of regularization and observe how the decision surface changes with higher values.

The neural network is trained until the loss stops decreasing below a specific tolerance. The color of the decision surface represents the probability of observing the corresponding class.

Created by [@huabdul](https://huggingface.co/huabdul) based on [scikit-learn docs](https://scikit-learn.org/stable/auto_examples/neural_networks/plot_mlp_alpha.html).
'''
with gr.Blocks(analytics_enabled=False) as demo:
    with gr.Row():
        with gr.Column():
            gr.Markdown(info)
            dd_dataset = gr.Dropdown(list(datasets.keys()), value="Moons", label="Dataset", interactive=True)
            with gr.Row():
                with gr.Column(min_width=100):
                    s_alpha = gr.Slider(0, 4, value=0.1, step=0.05, label="α (regularization parameter)")
                    s_seed = gr.Slider(1, 1000, value=1, step=1, label="Seed")
                with gr.Column(min_width=100):
                    s_h1 = gr.Slider(2, 20, value=10, step=1, label="Hidden layer 1 size")
                    s_h2 = gr.Slider(2, 20, value=10, step=1, label="Hidden layer 2 size")
            submit = gr.Button("Submit")
        with gr.Column():
            plot = gr.Plot(show_label=False)
    
    submit.click(create_plot, inputs=[dd_dataset, s_alpha, s_h1, s_h2, s_seed], outputs=[plot])
    demo.load(create_plot, inputs=[dd_dataset, s_alpha, s_h1, s_h2, s_seed], outputs=[plot])

demo.launch()