PhragMMS election. (#6685)

* Revamp npos-elections and implement phragmms * Update primitives/npos-elections/src/phragmms.rs * Fix build * Some review grumbles * Add some stuff for remote testing * fix some of the grumbles. * Add remote testing stuff. * Cleanup * fix docs * Update primitives/arithmetic/src/rational.rs Co-authored-by: Dan Forbes <dan@danforbes.dev> * Small config change * Better handling of approval_stake == 0 * Final touhces. * Clean fuzzer a bit * Clean fuzzer a bit * Update primitives/npos-elections/src/balancing.rs Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com> * Fix fuzzer. * Better api for normalize * Add noramlize_up * A large number of small fixes. * make it merge ready * Fix warns * bump * Fix fuzzers a bit. * Fix warns as well. * Fix more tests. Co-authored-by: Dan Forbes <dan@danforbes.dev> Co-authored-by: Shawn Tabrizi <shawntabrizi@gmail.com>
2026-06-20 05:51:02 +00:00 · 2020-09-23 10:16:10 +02:00
parent ecdc94420e
commit 313f86ec23
32 changed files with 2074 additions and 914 deletions
@@ -0,0 +1,115 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Fuzzing for phragmms.
+
+mod common;
+
+use common::*;
+use honggfuzz::fuzz;
+use sp_npos_elections::{
+	assignment_ratio_to_staked_normalized, build_support_map, to_without_backing, VoteWeight,
+	evaluate_support, is_score_better, phragmms,
+};
+use sp_runtime::Perbill;
+use rand::{self, SeedableRng};
+
+fn main() {
+	loop {
+		fuzz!(|data: (usize, usize, usize, usize, u64)| {
+			let (
+				mut target_count,
+				mut voter_count,
+				mut iterations,
+				mut to_elect,
+				seed,
+			) = data;
+			let rng = rand::rngs::SmallRng::seed_from_u64(seed);
+			target_count = to_range(target_count, 100, 200);
+			voter_count = to_range(voter_count, 100, 200);
+			iterations = to_range(iterations, 5, 30);
+			to_elect = to_range(to_elect, 25, target_count);
+
+			println!(
+				"++ [voter_count: {} / target_count:{} / to_elect:{} / iterations:{}]",
+				voter_count, target_count, to_elect, iterations,
+			);
+			let (
+				unbalanced,
+				candidates,
+				voters,
+				stake_of_tree,
+			) = generate_random_npos_result(
+				voter_count as u64,
+				target_count as u64,
+				to_elect,
+				rng,
+				ElectionType::Phragmms(None),
+			);
+
+			let stake_of = |who: &AccountId| -> VoteWeight {
+				*stake_of_tree.get(who).unwrap()
+			};
+
+			let unbalanced_score = {
+				let staked = assignment_ratio_to_staked_normalized(unbalanced.assignments.clone(), &stake_of).unwrap();
+				let winners = to_without_backing(unbalanced.winners.clone());
+				let support = build_support_map(winners.as_ref(), staked.as_ref()).unwrap();
+
+				let score = evaluate_support(&support);
+				if score[0] == 0 {
+					// such cases cannot be improved by balancing.
+					return;
+				}
+				score
+			};
+
+			let balanced = phragmms::<AccountId, sp_runtime::Perbill>(
+				to_elect,
+				candidates,
+				voters,
+				Some((iterations, 0)),
+			).unwrap();
+
+			let balanced_score = {
+				let staked = assignment_ratio_to_staked_normalized(balanced.assignments.clone(), &stake_of).unwrap();
+				let winners = to_without_backing(balanced.winners);
+				let support = build_support_map(winners.as_ref(), staked.as_ref()).unwrap();
+
+				evaluate_support(&support)
+			};
+
+			let enhance = is_score_better(balanced_score, unbalanced_score, Perbill::zero());
+
+			println!(
+				"iter = {} // {:?} -> {:?} [{}]",
+				iterations,
+				unbalanced_score,
+				balanced_score,
+				enhance,
+			);
+
+			// The only guarantee of balancing is such that the first and third element of the score
+			// cannot decrease.
+			assert!(
+				balanced_score[0] >= unbalanced_score[0] &&
+				balanced_score[1] == unbalanced_score[1] &&
+				balanced_score[2] <= unbalanced_score[2]
+			);
+		});
+	}
+}