Calculate Average of vectors in Presto

customer_mean_event_vector.sql

    SELECT 
    customer_id, 
    reduce(
	    event_vectors,
	    repeat(0.0, 512), -- dimension of vector here it is 512
	    (sum_array, element_array) -> zip_with(sum_array, element_array, (s, e) -> s + e), 
	    state_array -> transform(state_array, s -> s / cardinality(event_vectors))
    ) as mean_event_vector
    FROM(
        SELECT 
            customer_id, 
            ARRAY_AGG(
                event_vector
            ) AS event_vectors
        FROM customer_behaviour_features 
        WHERE date BETWEEN '{start_date}' AND '{end_date}'
        GROUP BY customer_id
    )