trysklearn.py

import numpy as np
import matplotlib.pyplot as plt
from matplotlib.colors import ListedColormap
from sklearn.model_selection import train_test_split
from sklearn.preprocessing import StandardScaler
from sklearn.datasets import make_moons, make_circles, make_classification
from sklearn.neural_network import MLPClassifier
from sklearn.neighbors import KNeighborsClassifier
from sklearn.svm import SVC
from sklearn.gaussian_process import GaussianProcessClassifier
from sklearn.gaussian_process.kernels import RBF
from sklearn.tree import DecisionTreeClassifier
from sklearn.ensemble import RandomForestClassifier, AdaBoostClassifier
from sklearn.naive_bayes import GaussianNB
from sklearn.discriminant_analysis import QuadraticDiscriminantAnalysis
from sklearn.inspection import DecisionBoundaryDisplay


def plot_classifiers():

    names = [
        "Nearest Neighbors",
        "Linear SVM",
        "RBF SVM",
        "Gaussian Process",
        "Decision Tree",
        "Random Forest",
        "Neural Net",
        "AdaBoost",
        "Naive Bayes",
        "QDA",
    ]

    classifiers = [
        KNeighborsClassifier(3),
        SVC(kernel="linear", C=0.025),
        SVC(gamma=2, C=1),
        GaussianProcessClassifier(1.0 * RBF(1.0)),
        DecisionTreeClassifier(max_depth=5),
        RandomForestClassifier(max_depth=5, n_estimators=10, max_features=1),
        MLPClassifier(alpha=1, max_iter=1000),
        AdaBoostClassifier(),
        GaussianNB(),
        QuadraticDiscriminantAnalysis(),
    ]

    X, y = make_classification(
        n_features=2, n_redundant=0, n_informative=2, random_state=1, n_clusters_per_class=1
    )
    rng = np.random.RandomState(2)
    X += 2 * rng.uniform(size=X.shape)
    linearly_separable = (X, y)

    datasets = [
        make_moons(noise=0.3, random_state=0),
        make_circles(noise=0.2, factor=0.5, random_state=1),
        linearly_separable,
    ]

    figure = plt.figure(figsize=(27, 9))
    i = 1
    # iterate over datasets
    for ds_cnt, ds in enumerate(datasets):
        # preprocess dataset, split into training and test part
        X, y = ds
        X = StandardScaler().fit_transform(X)
        X_train, X_test, y_train, y_test = train_test_split(
            X, y, test_size=0.4, random_state=42
        )

        x_min, x_max = X[:, 0].min() - 0.5, X[:, 0].max() + 0.5
        y_min, y_max = X[:, 1].min() - 0.5, X[:, 1].max() + 0.5

        # just plot the dataset first
        cm = plt.cm.RdBu
        cm_bright = ListedColormap(["#FF0000", "#0000FF"])
        ax = plt.subplot(len(datasets), len(classifiers) + 1, i)
        if ds_cnt == 0:
            ax.set_title("Input data")
        # Plot the training points
        ax.scatter(X_train[:, 0], X_train[:, 1], c=y_train, cmap=cm_bright, edgecolors="k")
        # Plot the testing points
        ax.scatter(
            X_test[:, 0], X_test[:, 1], c=y_test, cmap=cm_bright, alpha=0.6, edgecolors="k"
        )
        ax.set_xlim(x_min, x_max)
        ax.set_ylim(y_min, y_max)
        ax.set_xticks(())
        ax.set_yticks(())
        i += 1

        # iterate over classifiers
        for name, clf in zip(names, classifiers):
            ax = plt.subplot(len(datasets), len(classifiers) + 1, i)
            clf.fit(X_train, y_train)
            score = clf.score(X_test, y_test)
            DecisionBoundaryDisplay.from_estimator(
                clf, X, cmap=cm, alpha=0.8, ax=ax, eps=0.5
            )

            # Plot the training points
            ax.scatter(
                X_train[:, 0], X_train[:, 1], c=y_train, cmap=cm_bright, edgecolors="k"
            )
            # Plot the testing points
            ax.scatter(
                X_test[:, 0],
                X_test[:, 1],
                c=y_test,
                cmap=cm_bright,
                edgecolors="k",
                alpha=0.6,
            )

            ax.set_xlim(x_min, x_max)
            ax.set_ylim(y_min, y_max)
            ax.set_xticks(())
            ax.set_yticks(())
            if ds_cnt == 0:
                ax.set_title(name)
            ax.text(
                x_max - 0.3,
                y_min + 0.3,
                ("%.2f" % score).lstrip("0"),
                size=15,
                horizontalalignment="right",
            )
            i += 1

    plt.tight_layout()
    plt.show()


if __name__ == "__main__":
    plot_classifiers()