RCIR is a ranked choice instant runoff library written in rust. It's a work in progress. The library is in the rcir directory, and a sample binary is in the rcir_csv directory.
In the result of a tie for last place and no winner, all the last place candidates are removed, so it is not a 'Spoiler Proof' method Spoiler Effect + Resistance to tactical voting
RCIR will not mutate the input and aims to have as few restrictions on data types as possible
| Voter A | Voter B | Voter C | Voter D | Voter E |
|---|---|---|---|---|
| Bob | Sue | Bill | Bob | Sue |
| Bill | Bob | Sue | Bill | Bob |
| Sue | Bill | Bob | Sue | Bill |
This would result in an ElectionResult::Winner(&"sue") under either operational mode
| Voter A | Voter B |
|---|---|
| Bob | Sue |
This would result in an ElectionResult::Tie([&"Bob", &"Sue"]) under either operational mode
RCIR has 2 modes of operation:
- Complete Majority
- Remaining Majority
The differences between the two can best be explained with this sample:
| Voter A | Voter B | Voter C | Voter D | Voter E |
|---|---|---|---|---|
| Alice | Bob | Chris | Sam | Alice |
| Sam | Sam | Bob | Chris | Chris |
Bob, Chris, and Sam are eliminated (lowest vote getters)
| Voter A | Voter B | Voter C | Voter D | Voter E |
|---|---|---|---|---|
| Alice | _ | _ | _ | Alice |
| _ | _ | _ | _ | _ |
Under CompleteMajority, there is no winner and the result would be: ElectionError::NoMajorityWinner because Alice has 2/5 votes, which is below the 50% threshold for a complete majority.
Under RemainingMajority, the result would be an ElectionResult::Winner(&"Alice") because Alice has 100% (2/2) of the remaining ballots of voters who still have candidates left.