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Plot individual and voting regression predictions¶
A voting regressor is an ensemble meta-estimator that fits several base
regressors, each on the whole dataset. Then it averages the individual
predictions to form a final prediction.
We will use three different regressors to predict the data:
GradientBoostingRegressor
,
RandomForestRegressor
, and
LinearRegression
).
Then the above 3 regressors will be used for the
VotingRegressor
.
Finally, we will plot the predictions made by all models for comparison.
We will work with the diabetes dataset which consists of 10 features collected from a cohort of diabetes patients. The target is a quantitative measure of disease progression one year after baseline.
print(__doc__)
import matplotlib.pyplot as plt
from sklearn.datasets import load_diabetes
from sklearn.ensemble import GradientBoostingRegressor
from sklearn.ensemble import RandomForestRegressor
from sklearn.linear_model import LinearRegression
from sklearn.ensemble import VotingRegressor
Training classifiers¶
First, we will load the diabetes dataset and initiate a gradient boosting regressor, a random forest regressor and a linear regression. Next, we will use the 3 regressors to build the voting regressor:
X, y = load_diabetes(return_X_y=True)
# Train classifiers
reg1 = GradientBoostingRegressor(random_state=1)
reg2 = RandomForestRegressor(random_state=1)
reg3 = LinearRegression()
reg1.fit(X, y)
reg2.fit(X, y)
reg3.fit(X, y)
ereg = VotingRegressor([('gb', reg1), ('rf', reg2), ('lr', reg3)])
ereg.fit(X, y)
Making predictions¶
Now we will use each of the regressors to make the 20 first predictions.
xt = X[:20]
pred1 = reg1.predict(xt)
pred2 = reg2.predict(xt)
pred3 = reg3.predict(xt)
pred4 = ereg.predict(xt)
Plot the results¶
Finally, we will visualize the 20 predictions. The red stars show the average
prediction made by VotingRegressor
.
plt.figure()
plt.plot(pred1, 'gd', label='GradientBoostingRegressor')
plt.plot(pred2, 'b^', label='RandomForestRegressor')
plt.plot(pred3, 'ys', label='LinearRegression')
plt.plot(pred4, 'r*', ms=10, label='VotingRegressor')
plt.tick_params(axis='x', which='both', bottom=False, top=False,
labelbottom=False)
plt.ylabel('predicted')
plt.xlabel('training samples')
plt.legend(loc="best")
plt.title('Regressor predictions and their average')
plt.show()

Total running time of the script: ( 0 minutes 0.986 seconds)