Optimizing flights linear regression

Up until now you've been using the default hyper-parameters when building your models. In this exercise you'll use cross validation to choose an optimal (or close to optimal) set of model hyper-parameters.

The following have already been created:

regression — a LinearRegression object
pipeline — a pipeline with string indexer, one-hot encoder, vector assembler and linear regression and
evaluator — a RegressionEvaluator object.

Deze oefening maakt deel uit van de cursus

Machine Learning with PySpark

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Oefeninstructies

Create a parameter grid builder.
Add grids for with regression.regParam (values 0.01, 0.1, 1.0, and 10.0) and regression.elasticNetParam (values 0.0, 0.5, and 1.0).
Build the grid.
Create a cross validator, specifying five folds.

Praktische interactieve oefening

Probeer deze oefening eens door deze voorbeeldcode in te vullen.

# Create parameter grid
params = ____()

# Add grids for two parameters
params = params.____(____, ____) \
               .____(____, ____)

# Build the parameter grid
params = params.____()
print('Number of models to be tested: ', len(params))

# Create cross-validator
cv = ____(estimator=____, estimatorParamMaps=____, evaluator=____, ____)

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