tallystick

tallystick is a work-in-progress rust library for tallying votes.

Current state is very unstable. It is not currently recommended for use. See checkboxes below for a list of features that are complete.

Goals

1. Ergonomic - Easy to use.
2. Fast - Be the fastest general-purpose vote tallying library in the world.
3. Secure - Have no undefined behavior.
4. Complete - Support all well-known voting methods.
5. Deterministic - Running the same tally twice should never produce different results.
6. Generic - Generic over both candidate and count types.

Features

• wasm support for use in the browser, or in blockchain smart contracts.
• rational support for perfectly-precise tallies by using rational fractions instead of floats.
• fixed_point support for decimal fixed-point tallies, required by some statutes.
• ffi support for calling from other programming languages.
• alloc support for embedded and other applications where there is an allocator, but no standard library.

Supported Tally Methods

Status¹	Tally Method	Supported Variants	Performance²	Notes
✓	Plurality		120 million v/s	First Past the Post (FPTP)
✓	Score		3 million v/s
✓	Approval		4 million v/s
⚠	STV	Newland-Britton, Meek, Warren	3 million v/s	Single Transferable Vote
	CPO-STV
⚠	Instant Runoff
	Contingent
	Supplementary
✓	Condorcet		2 million v/s
	Copeland
✓	Schulze	Winning, Margin, Ratio	2 million v/s
	Schulze STV
	Kemeny–Young
	Minimax
✓	Borda	Classic, Dowdall, Modified	3 million v/s
	Borda - Nanson	Classic, Dowdall, Modified
	Borda - Baldwin	Classic, Dowdall, Modified
	Dodgson	Quick, Tideman
	Ranked pairs	Margin, Winning
	STAR
	Majority judgment
	D'Hondt	Sainte-Laguë, Huntington-Hill, Quota

1. ✓ means done, ⚠ means in-progress, blank means not started but support is planned.
2. Single threaded performance measured in votes tallied per second. Benchmarked on a 2017 Macbook Pro.

Contributors

• Patrick Hayes (linkedin) (github) - Available for hire.
• Kurtis Jensen (github)