/// <inheritdoc/>
protected override void SetState(Candidate candidate, CandidateState.States state)
{
if (!candidateStates.ContainsKey(candidate))
{
candidateStates[candidate] = new MeekCandidateState();
}
base.SetState(candidate, state);
// Set KeepFactor to 0 for losers as per B.3
if (new[] { CandidateState.States.defeated, CandidateState.States.withdrawn }
.Contains(candidateStates[candidate].State))
{
(candidateStates[candidate] as MeekCandidateState).KeepFactor = 0.0m;
}
}
/// <inheritdoc/>
protected override void CountBallot(CountedBallot ballot)
{
decimal weight = 1.0m;
List <Vote> votes = ballot.Votes.ToList();
// Ensure any newly-seen candidates are counted
List <Candidate> c = ballot.Votes.Where(x => !candidateStates.Keys.Contains(x.Candidate))
.Select(x => x.Candidate).ToList();
InitializeCandidateStates(c);
votes.Sort();
foreach (Vote v in votes)
{
MeekCandidateState cs = candidateStates[v.Candidate] as MeekCandidateState;
if (cs is null)
{
throw new InvalidOperationException("candidateState contains objects that aren't of type MeekCandidateState");
}
// Get value to transfer to this candidate, restricted to
// the specified precision
decimal value = weight * cs.KeepFactor;
weight = RoundUp(weight);
// Add this to the candidate's vote and remove from ballot's
// weight. CountedBallot shows multiple identical ballots, so
// we add that many ballots to the vote and decrease the weight
// of all identical ballots by the value kept.
cs.VoteCount += value * ballot.Count;
weight -= value;
// Do this until weight hits zero, or we run out of rankings.
// Note: Already-elected candidates have keep factors between
// 0 and 1; hopefuls all have 1; defeated will have 0. The
// remaining voting power is either all transfered to the first
// hopeful candidate or exhausted as the ballot runs out of
// non-defeated candidates.
//
// We only hit 0 if a non-elected hopeful is on the ballot.
if (weight <= 0.0m)
{
break;
}
}
}
