Improve performance of probability distribution function

[zmek]

Describe the Bug

predict.emergency_demand.from_individual_probs.get_prob_dist_for_prediction_moment() returns a probability distribution over the number of rows in X_test. When there are many rows in the snapshot, performance is very slow. This is due to the cumulative product expression in build_expression().

To Reproduce

https://github.com/zmek/zbeds/blob/zbeds2-discharge-modelling/models/discharges/notebooks/Python_model_discharges.ipynb

Expected Behaviour

Was as expected but very slow

Actual Behaviour

Consider truncating the distribution based on the number of observed patients?

Version In Use

0

Additional Context

- Python version:
- Operating system: