Propagate votes example

vote.py

from scipy import sparse


class Proposition:
    def __init__(self, title):
        self.title = title
        self.votes = {}
        self.delegations = {}

    def vote(self, user, vote):
        # TODO: Remove possible delegation
        self.votes[user] = vote

    def delegate(self, delegator, delegatee):
        # TODO: Check delegator hasn't voted
        self.delegations[delegator] = delegatee

    def get_explicit_votes(self, num_users):
        users, votes = zip(*self.votes.items())
        explicit_votes = sparse.csr_matrix(
                (votes, ([0] * len(users), users)), shape=(1, num_users))

        delegators, delegatees = zip(*self.delegations.items())
        delegations = sparse.csc_matrix(
                ([1] * len(self.delegations), (delegatees, delegators)),
                shape=(num_users, num_users))

        return self._propagate(explicit_votes, delegations)

    def _propagate(self, votes, delegations):
        voted = votes
        while len(voted.data):
            voted @= delegations
            votes += voted

        return votes


def main():
    p = Proposition("More cookies")
    p.vote(0, 1)
    p.vote(2, 0)
    p.vote(1, -1)

    p.delegate(4, 0)
    p.delegate(5, 4)

    votes = p.get_explicit_votes(6)

    print(votes.todense())


if __name__ == '__main__':
    main()

Nice. Fikk kjørt det. Output:
[[ 1 -1 0 0 1 1]]

Ja, vil si at bruker 0 stemte "1", bruker 1: "-1" og e.g. bruker 4 stemte samme som bruker 0 og bruker 5 stemte samme som bruker 4