Prepare for dynamic quota: independent flag for completion of surplus transfers/exclusions

src/election.rs

@@ -294,10 +294,11 @@ pub struct CountCard<'a, N> {
 	pub state: CandidateState,
 	/// Order of election or exclusion
 	///
-	/// Positive integers represent order of election; negative integers represent order of exclusion
+	/// Positive integers represent order of election; negative integers represent order of exclusion.
 	pub order_elected: isize,
+	/// Whether distribution of this candidate's surpluses/transfer of excluded candidate's votes is complete
+	pub finalised: bool,
 	
-	//pub orig_votes: N,
 	/// Net votes transferred to this candidate in this stage
 	pub transfers: N,
 	/// Votes of the candidate at the end of this stage
@@ -316,7 +317,7 @@ impl<'a, N: Number> CountCard<'a, N> {
 		return CountCard {
 			state: CandidateState::Hopeful,
 			order_elected: 0,
-			//orig_votes: N::new(),
+			finalised: false,
 			transfers: N::new(),
 			votes: N::new(),
 			parcels: Vec::new(),

src/stv/gregory.rs

@@ -75,7 +75,7 @@ where
 	let has_surplus: Vec<&Candidate> = state.election.candidates.iter() // Present in order in case of tie
 		.filter(|c| {
 			let cc = &state.candidates[c];
-			&cc.votes > quota && cc.parcels.iter().any(|p| !p.votes.is_empty())
+			&cc.votes > quota && !cc.finalised
 		})
 		.collect();
 	
@@ -388,7 +388,7 @@ where
 	count_card.votes.assign(state.quota.as_ref().unwrap());
 	checksum -= surplus;
 	
-	count_card.parcels.clear(); // Mark surpluses as done
+	count_card.finalised = true; // Mark surpluses as done
 	
 	// Update loss by fraction
 	state.loss_fraction.transfer(&-checksum);
@@ -426,7 +426,7 @@ where
 			for excluded_candidate in excluded_candidates.iter() {
 				let count_card = state.candidates.get_mut(excluded_candidate).unwrap();
 				votes.append(&mut count_card.concat_parcels());
-				count_card.parcels.clear();
+				count_card.finalised = true;
 				
 				// Update votes
 				let votes_transferred = votes.iter().fold(N::new(), |acc, v| acc + &v.value);
@@ -437,7 +437,7 @@ where
 		}
 		ExclusionMethod::ByValue => {
 			// Exclude by value
-			let excluded_with_votes: Vec<&&Candidate> = excluded_candidates.iter().filter(|c| !state.candidates[*c].parcels.is_empty()).collect();
+			let excluded_with_votes: Vec<&&Candidate> = excluded_candidates.iter().filter(|c| !state.candidates[*c].finalised).collect();
 			
 			if excluded_with_votes.is_empty() {
 				votes_remain = false;
@@ -487,7 +487,7 @@ where
 		}
 		ExclusionMethod::BySource => {
 			// Exclude by source candidate
-			let excluded_with_votes: Vec<&&Candidate> = excluded_candidates.iter().filter(|c| !state.candidates[*c].parcels.is_empty()).collect();
+			let excluded_with_votes: Vec<&&Candidate> = excluded_candidates.iter().filter(|c| !state.candidates[*c].finalised).collect();
 			
 			if excluded_with_votes.is_empty() {
 				votes_remain = false;
@@ -617,6 +617,7 @@ where
 			checksum -= &count_card.votes;
 			count_card.transfers -= &count_card.votes;
 			count_card.votes = N::new();
+			count_card.finalised = true;
 		}
 		
 		if let ExclusionMethod::SingleStage = opts.exclusion {
@@ -665,6 +666,12 @@ where
 			CandidateState::Excluded => CandidateState::Excluded,
 			_ => CandidateState::Hopeful,
 		};
+		
+		if count_card.state == CandidateState::Excluded {
+			count_card.finalised = true;
+		} else {
+			count_card.finalised = false;
+		}
 	}
 	
 	state.exhausted.votes = N::new();

src/stv/meek.rs

@@ -389,6 +389,7 @@ where
 			count_card.state = CandidateState::Excluded;
 			state.num_excluded += 1;
 			count_card.order_elected = -(order_excluded as isize);
+			count_card.finalised = true;
 		}
 	}
 	

src/stv/mod.rs

@@ -783,7 +783,7 @@ fn update_vre<N: Number>(state: &mut CountState<N>, opts: &STVOptions) {
 	// Calculate total active vote
 	let total_active_vote = state.candidates.values().fold(N::zero(), |acc, cc| {
 		match cc.state {
-			CandidateState::Elected => { if &cc.votes > state.quota.as_ref().unwrap() { acc + &cc.votes - state.quota.as_ref().unwrap() } else { acc } }
+			CandidateState::Elected => { if !cc.finalised && &cc.votes > state.quota.as_ref().unwrap() { acc + &cc.votes - state.quota.as_ref().unwrap() } else { acc } }
 			_ => { acc + &cc.votes }
 		}
 	});
@@ -923,7 +923,7 @@ fn elect_sure_winners<'a, N: Number>(state: &mut CountState<'a, N>, opts: &STVOp
 	// Add finally any votes awaiting transfer
 	total_trailing += state.candidates.values().fold(N::zero(), |acc, cc| {
 		match cc.state {
-			CandidateState::Elected => { if &cc.votes > state.quota.as_ref().unwrap() { acc + &cc.votes - state.quota.as_ref().unwrap() } else { acc } }
+			CandidateState::Elected => { if !cc.finalised && &cc.votes > state.quota.as_ref().unwrap() { acc + &cc.votes - state.quota.as_ref().unwrap() } else { acc } }
 			CandidateState::Hopeful | CandidateState::Guarded | CandidateState::Withdrawn => { acc }
 			CandidateState::Excluded | CandidateState::Doomed => { acc + &cc.votes }
 		}
@@ -1275,7 +1275,7 @@ fn hopefuls_to_bulk_exclude<'a, N: Number>(state: &CountState<'a, N>, _opts: &ST
 	hopefuls.sort_unstable_by(|a, b| a.1.votes.cmp(&b.1.votes));
 	
 	let total_surpluses = state.candidates.iter()
-		.filter(|(_, cc)| &cc.votes > state.quota.as_ref().unwrap())
+		.filter(|(_, cc)| !cc.finalised && &cc.votes > state.quota.as_ref().unwrap())
 		.fold(N::new(), |agg, (_, cc)| agg + &cc.votes - state.quota.as_ref().unwrap());
 	
 	// Attempt to exclude as many candidates as possible
@@ -1387,7 +1387,7 @@ where
 {
 	// Cannot filter by raw vote count, as candidates may have 0.00 votes but still have recorded ballot papers
 	let mut excluded_with_votes: Vec<(&&Candidate, &CountCard<N>)> = state.candidates.iter()
-		.filter(|(_, cc)| cc.state == CandidateState::Excluded && cc.parcels.iter().any(|p| !p.votes.is_empty()))
+		.filter(|(_, cc)| cc.state == CandidateState::Excluded && !cc.finalised)
 		.collect();
 	
 	if !excluded_with_votes.is_empty() {

src/stv/sample.rs

@@ -181,7 +181,7 @@ where
 			count_card.votes.assign(state.quota.as_ref().unwrap());
 			checksum -= surplus;
 			
-			count_card.parcels.clear(); // Mark surpluses as done
+			count_card.finalised = true; // Mark surpluses as done
 			
 			// Update loss by fraction
 			state.loss_fraction.transfer(&-checksum);
@@ -386,7 +386,6 @@ where
 	for excluded_candidate in excluded_candidates.iter() {
 		let count_card = state.candidates.get_mut(excluded_candidate).unwrap();
 		let votes = count_card.concat_parcels();
-		count_card.parcels.clear();
 		
 		for vote in votes {
 			transfer_ballot(state, opts, excluded_candidate, vote, false)?;
@@ -394,6 +393,9 @@ where
 				return Ok(());
 			}
 		}
+		
+		let count_card = state.candidates.get_mut(excluded_candidate).unwrap();
+		count_card.finalised = true;
 	}
 	
 	return Ok(());