248 lines
8.5 KiB
Rust
248 lines
8.5 KiB
Rust
/* OpenTally: Open-source election vote counting
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* Copyright © 2021 Lee Yingtong Li (RunasSudo)
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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use opentally::stv;
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use opentally::election::{Candidate, CandidateState, CountCard, CountState, CountStateOrRef, Election, StageResult};
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use opentally::numbers::{NativeFloat64, Number, Rational};
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use clap::{AppSettings, Clap};
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use git_version::git_version;
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use std::fs::File;
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use std::io::{self, BufRead};
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use std::ops;
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const VERSION: &str = git_version!(args=["--always", "--dirty=-dev"], fallback="unknown");
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/// Open-source election vote counting
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#[derive(Clap)]
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#[clap(name="OpenTally", version=VERSION)]
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struct Opts {
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#[clap(subcommand)]
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command: Command,
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}
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#[derive(Clap)]
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enum Command {
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STV(STV),
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}
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/// Count a single transferable vote (STV) election
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#[derive(Clap)]
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#[clap(setting=AppSettings::DeriveDisplayOrder)]
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struct STV {
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// ----------------
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// -- File input --
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/// Path to the BLT file to be counted
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filename: String,
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// ----------------------
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// -- Numbers settings --
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/// Numbers mode
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#[clap(help_heading=Some("NUMBERS"), short, long, possible_values=&["rational", "float64"], default_value="rational", value_name="mode")]
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numbers: String,
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// -----------------------
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// -- Rounding settings --
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/// Round transfer values to specified decimal places
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#[clap(help_heading=Some("ROUNDING"), long, value_name="dps")]
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round_tvs: Option<usize>,
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/// Round ballot weights to specified decimal places
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#[clap(help_heading=Some("ROUNDING"), long, value_name="dps")]
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round_weights: Option<usize>,
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/// Round votes to specified decimal places
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#[clap(help_heading=Some("ROUNDING"), long, value_name="dps")]
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round_votes: Option<usize>,
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/// Round quota to specified decimal places
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#[clap(help_heading=Some("ROUNDING"), long, value_name="dps")]
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round_quota: Option<usize>,
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// ------------------
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// -- STV variants --
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/// Method of surplus transfers
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#[clap(help_heading=Some("STV VARIANTS"), long, possible_values=&["wig", "uig", "eg", "meek"], default_value="wig", value_name="method")]
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surplus: String,
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#[clap(help_heading=Some("STV VARIANTS"), long, possible_values=&["by_size", "by_order"], default_value="by_size", value_name="order")]
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surplus_order: String,
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/// Examine only transferable papers during surplus distributions
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#[clap(help_heading=Some("STV VARIANTS"), long)]
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transferable_only: bool,
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/// Method of exclusions
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#[clap(help_heading=Some("STV VARIANTS"), long, possible_values=&["single_stage", "by_value", "parcels_by_order"], default_value="single_stage", value_name="method")]
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exclusion: String,
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// ----------------------
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// -- Display settings --
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/// Hide excluded candidates from results report
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#[clap(help_heading=Some("DISPLAY"), long)]
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hide_excluded: bool,
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/// Sort candidates by votes in results report
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#[clap(help_heading=Some("DISPLAY"), long)]
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sort_votes: bool,
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/// Print votes to specified decimal places in results report
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#[clap(help_heading=Some("DISPLAY"), long, default_value="2", value_name="dps")]
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pp_decimals: usize,
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}
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fn main() {
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// Read arguments
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let opts: Opts = Opts::parse();
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let Command::STV(cmd_opts) = opts.command;
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// Read BLT file
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let file = File::open(&cmd_opts.filename).expect("IO Error");
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let lines = io::BufReader::new(file).lines();
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// Create and count election according to --numbers
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if cmd_opts.numbers == "rational" {
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let election: Election<Rational> = Election::from_blt(lines.map(|r| r.expect("IO Error").to_string()).into_iter());
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count_election(election, cmd_opts);
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} else if cmd_opts.numbers == "float64" {
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let election: Election<NativeFloat64> = Election::from_blt(lines.map(|r| r.expect("IO Error").to_string()).into_iter());
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count_election(election, cmd_opts);
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}
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}
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fn count_election<N: Number>(election: Election<N>, cmd_opts: STV)
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where
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for<'r> &'r N: ops::Sub<&'r N, Output=N>,
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for<'r> &'r N: ops::Div<&'r N, Output=N>,
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for<'r> &'r N: ops::Neg<Output=N>
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{
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// Copy applicable options
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let stv_opts = stv::STVOptions::new(
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cmd_opts.round_tvs,
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cmd_opts.round_weights,
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cmd_opts.round_votes,
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cmd_opts.round_quota,
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&cmd_opts.surplus,
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&cmd_opts.surplus_order,
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cmd_opts.transferable_only,
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&cmd_opts.exclusion,
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cmd_opts.pp_decimals,
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);
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// Initialise count state
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let mut state = CountState::new(&election);
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// Distribute first preferences
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stv::count_init(&mut state, &stv_opts);
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let mut stage_num = 1;
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make_and_print_result(stage_num, &state, &cmd_opts);
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loop {
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let is_done = stv::count_one_stage(&mut state, &stv_opts);
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if is_done {
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break;
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}
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stage_num += 1;
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make_and_print_result(stage_num, &state, &cmd_opts);
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}
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println!("Count complete. The winning candidates are, in order of election:");
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let mut winners = Vec::new();
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for (candidate, count_card) in state.candidates.iter() {
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if count_card.state == CandidateState::ELECTED {
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winners.push((candidate, count_card.order_elected));
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}
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}
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winners.sort_unstable_by(|a, b| a.1.partial_cmp(&b.1).unwrap());
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for (i, (winner, _)) in winners.into_iter().enumerate() {
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println!("{}. {}", i + 1, winner.name);
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}
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}
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fn print_candidates<'a, N: 'a + Number, I: Iterator<Item=(&'a Candidate, &'a CountCard<'a, N>)>>(candidates: I, cmd_opts: &STV) {
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for (candidate, count_card) in candidates {
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if count_card.state == CandidateState::ELECTED {
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println!("- {}: {:.dps$} ({:.dps$}) - ELECTED {}", candidate.name, count_card.votes, count_card.transfers, count_card.order_elected, dps=cmd_opts.pp_decimals);
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} else if count_card.state == CandidateState::EXCLUDED {
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// If --hide-excluded, hide unless nonzero votes or nonzero transfers
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if !cmd_opts.hide_excluded || !count_card.votes.is_zero() || !count_card.transfers.is_zero() {
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println!("- {}: {:.dps$} ({:.dps$}) - Excluded {}", candidate.name, count_card.votes, count_card.transfers, -count_card.order_elected, dps=cmd_opts.pp_decimals);
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}
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} else {
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println!("- {}: {:.dps$} ({:.dps$})", candidate.name, count_card.votes, count_card.transfers, dps=cmd_opts.pp_decimals);
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}
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}
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}
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fn print_stage<N: Number>(stage_num: usize, result: &StageResult<N>, cmd_opts: &STV) {
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// Print stage details
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match result.kind {
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None => { println!("{}. {}", stage_num, result.title); }
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Some(kind) => { println!("{}. {} {}", stage_num, kind, result.title); }
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};
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println!("{}", result.logs.join(" "));
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let state = result.state.as_ref();
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// Print candidates
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if cmd_opts.sort_votes {
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// Sort by votes if requested
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let mut candidates: Vec<(&Candidate, &CountCard<N>)> = state.candidates.iter()
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.map(|(c, cc)| (*c, cc)).collect();
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// First sort by order of election (as a tie-breaker, if votes are equal)
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candidates.sort_unstable_by(|a, b| b.1.order_elected.partial_cmp(&a.1.order_elected).unwrap());
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// Then sort by votes
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candidates.sort_by(|a, b| a.1.votes.partial_cmp(&b.1.votes).unwrap());
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print_candidates(candidates.into_iter().rev(), cmd_opts);
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} else {
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let candidates = state.election.candidates.iter()
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.map(|c| (c, state.candidates.get(c).unwrap()));
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print_candidates(candidates, cmd_opts);
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}
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// Print summary rows
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println!("Exhausted: {:.dps$} ({:.dps$})", state.exhausted.votes, state.exhausted.transfers, dps=cmd_opts.pp_decimals);
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println!("Loss by fraction: {:.dps$} ({:.dps$})", state.loss_fraction.votes, state.loss_fraction.transfers, dps=cmd_opts.pp_decimals);
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let mut total_vote = state.candidates.values().fold(N::zero(), |acc, cc| { acc + &cc.votes });
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total_vote += &state.exhausted.votes;
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total_vote += &state.loss_fraction.votes;
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println!("Total votes: {:.dps$}", total_vote, dps=cmd_opts.pp_decimals);
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println!("Quota: {:.dps$}", state.quota, dps=cmd_opts.pp_decimals);
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println!("");
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}
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fn make_and_print_result<N: Number>(stage_num: usize, state: &CountState<N>, cmd_opts: &STV) {
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let result = StageResult {
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kind: state.kind,
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title: &state.title,
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logs: state.logger.render(),
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state: CountStateOrRef::from(&state),
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};
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print_stage(stage_num, &result, &cmd_opts);
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}
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