Get RMSE
Now that you know how to build a model and generate predictions, and have an evaluator to tell us how well it predicts ratings, we can calculate the RMSE to see how well an ALS model performed. We'll use the evaluator
that we built in the previous exercise to calculate and print the rmse.
This exercise is part of the course
Building Recommendation Engines with PySpark
Exercise instructions
- Call the
.evaluate()
method on ourevaluator
to calculate our RMSE on thetest_predictions
dataframe. Call the resultRMSE
. - Print the
RMSE
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Evaluate the "test_predictions" dataframe
RMSE = evaluator.____(____)
# Print the RMSE
print (____)