app.py

import gradio as gr
import matplotlib.pyplot as plt
import numpy as np
from sklearn.ensemble import RandomForestClassifier, VotingClassifier
from sklearn.linear_model import LogisticRegression
from sklearn.naive_bayes import GaussianNB


def choose_model(model):
    if model == "Logistic Regression":
        return LogisticRegression(max_iter=1000, random_state=123)
    elif model == "Random Forest":
        return RandomForestClassifier(n_estimators=100, random_state=123)
    elif model == "Gaussian Naive Bayes":
        return GaussianNB()
    else:
        raise ValueError("Model is not supported.")


def get_proba_plots(
    model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight
):
    clf1 = choose_model(model_1)
    clf2 = choose_model(model_2)
    clf3 = choose_model(model_3)
    X = np.array([[-1.0, -1.0], [-1.2, -1.4], [-3.4, -2.2], [1.1, 1.2]])
    y = np.array([1, 1, 2, 2])

    eclf = VotingClassifier(
        estimators=[("clf1", clf1), ("clf2", clf2), ("clf3", clf3)],
        voting="soft",
        weights=[model_1_weight, model_2_weight, model_3_weight],
    )

    # predict class probabilities for all classifiers
    probas = [c.fit(X, y).predict_proba(X) for c in (clf1, clf2, clf3, eclf)]

    # get class probabilities for the first sample in the dataset
    class1_1 = [pr[0, 0] for pr in probas]
    class2_1 = [pr[0, 1] for pr in probas]

    # plotting

    N = 4  # number of groups
    ind = np.arange(N)  # group positions
    width = 0.35  # bar width

    fig, ax = plt.subplots()

    # bars for classifier 1-3
    p1 = ax.bar(
        ind, np.hstack(([class1_1[:-1], [0]])), width, color="green", edgecolor="k"
    )
    p2 = ax.bar(
        ind + width,
        np.hstack(([class2_1[:-1], [0]])),
        width,
        color="lightgreen",
        edgecolor="k",
    )

    # bars for VotingClassifier
    ax.bar(ind, [0, 0, 0, class1_1[-1]], width, color="blue", edgecolor="k")
    ax.bar(
        ind + width, [0, 0, 0, class2_1[-1]], width, color="steelblue", edgecolor="k"
    )

    # plot annotations
    plt.axvline(2.8, color="k", linestyle="dashed")
    ax.set_xticks(ind + width)
    ax.set_xticklabels(
        [
            f"{model_2}\nweight {model_1_weight}",
            f"{model_1}\nweight {model_2_weight}",
            f"{model_3}\nweight {model_3_weight}",
            "VotingClassifier\n(average probabilities)",
        ],
        rotation=40,
        ha="right",
    )
    plt.ylim([0, 1])
    plt.title("Class probabilities for sample 1 by different classifiers")
    plt.legend([p1[0], p2[0]], ["class 1", "class 2"], loc="upper left")
    plt.tight_layout()
    plt.show()
    return fig


with gr.Blocks() as demo:
    with gr.Row():
        model_1 = gr.Dropdown(
            [
                "Logistic Regression",
                "Random Forest",
                "Gaussian Naive Bayes",
            ],
            label="Model 1",
            value="Logistic Regression",
        )
        model_2 = gr.Dropdown(
            [
                "Logistic Regression",
                "Random Forest",
                "Gaussian Naive Bayes",
            ],
            label="Model 2",
            value="Random Forest",
        )
        model_3 = gr.Dropdown(
            [
                "Logistic Regression",
                "Random Forest",
                "Gaussian Naive Bayes",
            ],
            label="Model 3",
            value="Gaussian Naive Bayes",
        )

    with gr.Row():
        model_1_weight = gr.Slider(
            minimum=1, maximum=10, value=1, label="Model 1 Weight", step=1
        )
        model_2_weight = gr.Slider(
            minimum=1, maximum=10, value=1, label="Model 2 Weight", step=1
        )
        model_3_weight = gr.Slider(
            minimum=1, maximum=10, value=5, label="Model 3 Weight", step=1
        )

    proba_plots = gr.Plot()

    model_1.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )
    model_2.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )
    model_3.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )
    model_1_weight.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )
    model_2_weight.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )
    model_3_weight.change(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )

    demo.load(
        get_proba_plots,
        [model_1, model_2, model_3, model_1_weight, model_2_weight, model_3_weight],
        proba_plots,
        queue=False,
    )

if __name__ == "__main__":
    demo.launch()