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"""
A comparison of different methods in GLM
Data comes from a random square matrix.
"""
from datetime import datetime
import numpy as np
from sklearn import linear_model
from sklearn.utils.bench import total_seconds
if __name__ == '__main__':
import pylab as pl
n_iter = 40
time_ridge = np.empty(n_iter)
time_ols = np.empty(n_iter)
time_lasso = np.empty(n_iter)
dimensions = 500 * np.arange(1, n_iter + 1)
for i in range(n_iter):
print 'Iteration %s of %s' % (i, n_iter)
n_samples, n_features = 10 * i + 3, 10 * i + 3
X = np.random.randn(n_samples, n_features)
Y = np.random.randn(n_samples)
start = datetime.now()
ridge = linear_model.Ridge(alpha=1.)
ridge.fit(X, Y)
time_ridge[i] = total_seconds(datetime.now() - start)
start = datetime.now()
ols = linear_model.LinearRegression()
ols.fit(X, Y)
time_ols[i] = total_seconds(datetime.now() - start)
start = datetime.now()
lasso = linear_model.LassoLars()
lasso.fit(X, Y)
time_lasso[i] = total_seconds(datetime.now() - start)
pl.xlabel('Dimesions')
pl.ylabel('Time (in seconds)')
pl.plot(dimensions, time_ridge, color='r')
pl.plot(dimensions, time_ols, color='g')
pl.plot(dimensions, time_lasso, color='b')
pl.legend(['Ridge', 'OLS', 'LassoLars'])
pl.axis('tight')
pl.show()
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