Python_machinelearning/Earlystop.py

from sklearn.base import clone
from sklearn.pipeline import Pipeline
from sklearn import preprocessing
from sklearn.preprocessing import PolynomialFeatures
import numpy as np
import matplotlib.pyplot as plt
from sklearn.linear_model import SGDRegressor
from sklearn.metrics import mean_squared_error
from sklearn.preprocessing import StandardScaler
from sklearn.model_selection import train_test_split

np.random.seed(42)
m = 100
X = 6 * np.random.rand(m, 1) - 3
y = 2 + X + 0.5 * X**2 + np.random.randn(m, 1)

plt.plot(X,y,".", label = "Datos originales")

X_train, X_val, y_train, y_val = train_test_split(X[:50], y[:50].ravel(), test_size=0.5, random_state=10)

poly_scaler = Pipeline([
        ("poly_features", PolynomialFeatures(degree=90, include_bias=False)),
        ("std_scaler", StandardScaler()),
    ])

X_train_poly_scaled = poly_scaler.fit_transform(X_train)
X_val_poly_scaled = poly_scaler.transform(X_val)


sgd_reg = SGDRegressor(max_iter=1, tol=-np.infty, warm_start=True, penalty=None,
                       learning_rate="constant", eta0=0.0005, random_state=42)
print(sgd_reg)
minimum_val_error = float("inf")
best_epoch = None
best_model = None
for epoch in range(1000):
    sgd_reg.fit(X_train_poly_scaled, y_train)  # continues where it left off
    y_val_predict = sgd_reg.predict(X_val_poly_scaled)
    val_error = mean_squared_error(y_val, y_val_predict)
    if val_error < minimum_val_error:
        minimum_val_error = val_error
        best_epoch = epoch
        best_model = clone(sgd_reg)


print(best_epoch)





sgd_reg = SGDRegressor(max_iter=best_epoch, tol=-np.infty, warm_start=True, penalty=None,
                       learning_rate="constant", eta0=0.0005, random_state=42)

poly_features = PolynomialFeatures(degree=2, include_bias=False)
X_pol = poly_features.fit_transform(X)

sgd_reg.fit(X_pol,y.ravel())
yout=sgd_reg.predict(X_pol)

plt.plot(X,yout,"*", label = "Predicciones")



# naming the x axis 
plt.xlabel('Eje X') 
# naming the y axis 
plt.ylabel('Eje Y') 
# giving a title to my graph 

plt.legend() 
plt.show()