Chinese Restaurant Next Table

Problem

In the Chinese restaurant process with concentration theta after n seated customers, return the probability that the next customer joins a table of size table_size. A new table (table_size = 0) has probability theta / (theta + n); an existing table has probability table_size / (theta + n).

Return 0.0 for invalid inputs.

Hint

The total weight is theta for new tables plus n for all seated customers.

Test cases

case 1

in: [1,0,0]

expected: 1

case 2

in: [1,5,10]

expected: 0.45454545454545453

case 3

in: [2,0,3]

expected: 0.4

case 4

in: [1,3,0]

expected: 0

Starter codePython

def crp_next_table_probability(theta, table_size, n):
    # Your code here
    pass

4 test cases · run your code against them in the editor