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Given the following text description, write Python code to implement the functionality described below step by step
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Description:
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Support Vector Regression (SVR) using linear and non-linear kernels
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Toy example of 1D regression using linear, polynomial and RBF kernels.
Step1:  Generate sample data
Step2:  Add noise to targets
Step3:  Fit regression model
Step4:  look at the results
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Python Code:
print(__doc__)
import numpy as np
from sklearn.svm import SVR
import matplotlib.pyplot as plt
Explanation: ===================================================================
Support Vector Regression (SVR) using linear and non-linear kernels
===================================================================
Toy example of 1D regression using linear, polynomial and RBF kernels.
End of explanation
X = np.sort(5 * np.random.rand(40, 1), axis=0)
y = np.sin(X).ravel()
Explanation: Generate sample data
End of explanation
y[::5] += 3 * (0.5 - np.random.rand(8))
Explanation: Add noise to targets
End of explanation
svr_rbf = SVR(kernel='rbf', C=1e3, gamma=0.1)
svr_lin = SVR(kernel='linear', C=1e3)
svr_poly = SVR(kernel='poly', C=1e3, degree=2)
y_rbf = svr_rbf.fit(X, y).predict(X)
y_lin = svr_lin.fit(X, y).predict(X)
y_poly = svr_poly.fit(X, y).predict(X)
Explanation: Fit regression model
End of explanation
lw = 2
plt.scatter(X, y, color='darkorange', label='data')
plt.hold('on')
plt.plot(X, y_rbf, color='navy', lw=lw, label='RBF model')
plt.plot(X, y_lin, color='c', lw=lw, label='Linear model')
plt.plot(X, y_poly, color='cornflowerblue', lw=lw, label='Polynomial model')
plt.xlabel('data')
plt.ylabel('target')
plt.title('Support Vector Regression')
plt.legend()
plt.show()
Explanation: look at the results
End of explanation
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