Regularizing changepoints

As stated earlier, Prophet will place 25 potential changepoints in the first 80% of the time series by default. To control Prophet’s automatic changepoint detection, you can modify both of these values with the n_changepoints and changepoint_range arguments during model instantiation. For example, changing the number of potential changepoints to 5 is done like this:

model = Prophet(seasonality_mode='multiplicative',
                yearly_seasonality=4,
                n_changepoints=5)

This results in five evenly spaced potential changepoints in the first 80% of the data, as shown here:

Figure 8.5 – Five potential changepoints

Or, you could instead force all 25 changepoints to lie not in the first 80% of data, but rather in the first 50%:

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