OpenTally

OpenTally is an application for counting various preferential voting elections, with an academic focus, and emphasis on configurability.

OpenTally may be used in a number of different ways:

• as an online web application, no installation or special software required
• as a standalone command line application
• as a Rust library within another application

Features

OpenTally accepts data in the BLT file format, and can count votes using:

• weighted inclusive Gregory STV (e.g. Scottish STV)
• unweighted inclusive Gregory STV (e.g. Australian Senate STV)
• exclusive Gregory STV (e.g. PRSA 1977 and ERS97)
• Meek STV – with tree-packed ballots for efficient computation
• Wright STV

OpenTally is highly customisable, including options for:

• different quotas and quota rules (e.g. exact Droop, Hare)
• calculations using fixed-point arithmetic, guarded fixed-point (quasi-exact) or exact rational numbers
• different tie breaking rules (backwards, random, manual) with auditable deterministic random number generation
• multiple constraints (e.g. affirmative action rules)
• equal rankings

Online usage

See the quick start guide for how to use OpenTally online.

Command line usage

OpenTally may also be invoked as a command line application. Run ./opentally --help to view help.

For example, run ./opentally stv path/to/blt_file.blt --ties backwards random --random-seed foobar.