Report vote required for election in relation to early bulk election

src/stv/mod.rs

@@ -801,7 +801,7 @@ fn total_to_quota<N: Number>(mut total: N, seats: usize, opts: &STVOptions) -> N
 }
 
 /// Update vote required for election according to ERS97/ERS76 rules
-fn update_vre<N: Number>(state: &mut CountState<N>, opts: &STVOptions) {
+fn update_vre_ers<N: Number>(state: &mut CountState<N>, opts: &STVOptions) {
 	if opts.quota_mode == QuotaMode::ERS76 && state.num_excluded == 0 && (state.num_elected == 0 || state.candidates.values().all(|cc| !cc.finalised)) {
 		// ERS76 rules: Do not update VRE until a surplus is distributed or candidate is excluded
 		state.vote_required_election = state.quota.clone();
@@ -819,7 +819,6 @@ fn update_vre<N: Number>(state: &mut CountState<N>, opts: &STVOptions) {
 	});
 	log.push_str(format!("Active vote is {:.dps$}, so the vote required for election is ", active_vote, dps=opts.pp_decimals).as_str());
 	
-	// TODO: Calculate according to --quota ?
 	let vote_req = active_vote / N::from(state.election.seats - state.num_elected + 1);
 	
 	if &vote_req < state.quota.as_ref().unwrap() {
@@ -906,10 +905,42 @@ fn calculate_quota<N: Number>(state: &mut CountState<N>, opts: &STVOptions) {
 		// Calculate vote required for election
 		
 		if state.num_elected < state.election.seats {
-			update_vre(state, opts);
+			update_vre_ers(state, opts);
 		}
 	} else {
-		// No ERS97/ERS76 rules, so no use of VRE
+		// No ERS97/ERS76 rules
+		
+		// If --early-bulk-elect and one candidate remains, VRE is half of the active vote
+		// For display purposes only
+		if opts.early_bulk_elect && (state.election.seats - state.num_elected) == 1 {
+			//let mut log = String::new();
+			
+			// Calculate active vote
+			let active_vote = state.candidates.values().fold(N::zero(), |acc, cc| {
+				match cc.state {
+					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 }
+				}
+			});
+			//log.push_str(format!("Active vote is {:.dps$}, so the vote required for election is ", active_vote, dps=opts.pp_decimals).as_str());
+			
+			let vote_req = active_vote / N::from(state.election.seats - state.num_elected + 1);
+			
+			if &vote_req < state.quota.as_ref().unwrap() {
+				// VRE is less than the quota
+				//if let Some(v) = &state.vote_required_election {
+				//	if &vote_req != v {
+						//log.push_str(format!("{:.dps$}.", vote_req, dps=opts.pp_decimals).as_str());
+						state.vote_required_election = Some(vote_req);
+						//state.logger.log_literal(log);
+				//	}
+				//} else {
+					//log.push_str(format!("{:.dps$}.", vote_req, dps=opts.pp_decimals).as_str());
+				//	state.vote_required_election = Some(vote_req);
+					//state.logger.log_literal(log);
+				//}
+			}
+		}
 	}
 }
 
@@ -927,10 +958,11 @@ fn cmp_quota_criterion<N: Number>(quota: &N, count_card: &CountCard<N>, opts: &S
 
 /// Determine if the given candidate meets the vote required to be elected, according to [STVOptions::quota_criterion] and [STVOptions::quota_mode]
 fn meets_vre<N: Number>(state: &CountState<N>, count_card: &CountCard<N>, opts: &STVOptions) -> bool {
-	if let Some(vre) = &state.vote_required_election {
+	if opts.quota_mode == QuotaMode::ERS97 || opts.quota_mode == QuotaMode::ERS76 {
 		// VRE is set because ERS97/ERS76 rules
-		return cmp_quota_criterion(vre, count_card, opts);
+		return cmp_quota_criterion(state.vote_required_election.as_ref().unwrap(), count_card, opts);
 	} else {
+		// VRE is set (if at all) for display purposes only so ignore it here
 		return cmp_quota_criterion(state.quota.as_ref().unwrap(), count_card, opts);
 	}
 }
@@ -986,7 +1018,15 @@ fn elect_sure_winners<'a, N: Number>(state: &mut CountState<'a, N>, opts: &STVOp
 		Err(_) => { return Ok(false); } // Bulk election conflicts with constraints
 	}
 	
-	// Bulk elect all leading candidates
+	// Bulk election is possible!
+	// Elect all leading candidates
+	
+	if num_vacancies > 1 {
+		// Update VRE
+		// (If num_vacancies == 1, this has already been done in calculate_quota)
+		state.vote_required_election = Some(total_trailing);
+	}
+	
 	while !leading_hopefuls.is_empty() && state.num_elected < state.election.seats {
 		let max_cands = ties::multiple_max_by(&leading_hopefuls, |c| &state.candidates[c].votes);
 		let candidate = if max_cands.len() > 1 {

src/stv/wasm.rs

@@ -318,8 +318,7 @@ fn describe_count<N: Number>(filename: String, election: &Election<N>, opts: &st
 
 #[inline]
 fn should_show_vre(opts: &stv::STVOptions) -> bool {
-	//return opts.quota_mode == stv::QuotaMode::ERS97 || opts.quota_mode == stv::QuotaMode::ERS76 || opts.early_bulk_elect;
-	return opts.quota_mode == stv::QuotaMode::ERS97 || opts.quota_mode == stv::QuotaMode::ERS76;
+	return opts.quota_mode == stv::QuotaMode::ERS97 || opts.quota_mode == stv::QuotaMode::ERS76 || opts.early_bulk_elect;
 }
 
 /// Generate the first column of the HTML results table