Sample from a Mallows distribution

mallows.py

# Adapted from https://github.com/martinlackner/abcvoting/blob/6aacadb0e3e70e4f83a82225b05730f72a6230d4/abcvoting/generate.py#L166

def mallows(reference_ranking, dispersion):
    distributions = []
    for i in range(len(reference_ranking)):
        distributions.append([dispersion ** (i - j) for j in range(i + 1)])
    while True:
        vote = []
        for i in range(len(reference_ranking)):
            pos = random.choices(range(i + 1), weights=distributions[i], k=1)[0]
            vote.insert(pos, reference_ranking[i])
        yield vote