Move phragmen benchmarks out of Staking (#3588)

* Move phragmen benches to.. phragmen.

* Move some basic phragmen tests to.. phragmen.

* Line-width

* Add phragmen equ implementation as flot

* Add phragmen equ implementation as flot

* Add mock and test file.
This commit is contained in:
Kian Paimani
2019-09-13 08:41:33 +02:00
committed by GitHub
parent 7b87cd206b
commit a6b5d1d155
10 changed files with 661 additions and 374 deletions
+4 -224
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@@ -37,6 +37,9 @@ use rstd::{prelude::*, collections::btree_map::BTreeMap};
use sr_primitives::PerU128;
use sr_primitives::traits::{Zero, Convert, Member, SimpleArithmetic};
mod mock;
mod tests;
/// Type used as the fraction.
type Fraction = PerU128;
@@ -355,7 +358,7 @@ pub fn elect<AccountId, Balance, FS, C>(
/// * `tolerance`: maximum difference that can occur before an early quite happens.
/// * `iterations`: maximum number of iterations that will be processed.
/// * `stake_of`: something that can return the stake stake of a particular candidate or voter.
pub fn equalize<Balance, AccountId, C, FS>(
pub fn equalize<Balance, AccountId, FS, C>(
mut assignments: Vec<(AccountId, Vec<PhragmenAssignment<AccountId>>)>,
supports: &mut SupportMap<AccountId>,
tolerance: ExtendedBalance,
@@ -489,226 +492,3 @@ fn do_equalize<Balance, AccountId, C>(
difference
}
#[cfg(test)]
mod tests {
use super::{elect, ACCURACY, PhragmenResult};
use sr_primitives::traits::{Convert, Member, SaturatedConversion};
use rstd::collections::btree_map::BTreeMap;
use support::assert_eq_uvec;
pub struct C;
impl Convert<u64, u64> for C {
fn convert(x: u64) -> u64 { x }
}
impl Convert<u128, u64> for C {
fn convert(x: u128) -> u64 { x.saturated_into() }
}
#[derive(Default, Debug)]
struct _Candidate<AccountId> {
who: AccountId,
score: f64,
approval_stake: f64,
elected: bool,
}
#[derive(Default, Debug)]
struct _Voter<AccountId> {
who: AccountId,
edges: Vec<_Edge<AccountId>>,
budget: f64,
load: f64,
}
#[derive(Default, Debug)]
struct _Edge<AccountId> {
who: AccountId,
load: f64,
candidate_index: usize,
}
type _PhragmenAssignment<AccountId> = (AccountId, f64);
#[derive(Debug)]
pub struct _PhragmenResult<AccountId> {
pub winners: Vec<AccountId>,
pub assignments: Vec<(AccountId, Vec<_PhragmenAssignment<AccountId>>)>
}
pub fn elect_poc<AccountId, FS>(
candidate_count: usize,
minimum_candidate_count: usize,
initial_candidates: Vec<AccountId>,
initial_voters: Vec<(AccountId, Vec<AccountId>)>,
stake_of: FS,
self_vote: bool,
) -> Option<_PhragmenResult<AccountId>> where
AccountId: Default + Ord + Member + Copy,
for<'r> FS: Fn(&'r AccountId) -> u64,
{
let mut elected_candidates: Vec<AccountId>;
let mut assigned: Vec<(AccountId, Vec<_PhragmenAssignment<AccountId>>)>;
let mut c_idx_cache = BTreeMap::<AccountId, usize>::new();
let num_voters = initial_candidates.len() + initial_voters.len();
let mut voters: Vec<_Voter<AccountId>> = Vec::with_capacity(num_voters);
let mut candidates = if self_vote {
initial_candidates.into_iter().map(|who| {
let stake = stake_of(&who) as f64;
_Candidate { who, approval_stake: stake, ..Default::default() }
})
.filter(|c| c.approval_stake != 0f64)
.enumerate()
.map(|(i, c)| {
let who = c.who;
voters.push(_Voter {
who: who.clone(),
edges: vec![
_Edge { who: who.clone(), candidate_index: i, ..Default::default() }
],
budget: c.approval_stake,
load: 0f64,
});
c_idx_cache.insert(c.who.clone(), i);
c
})
.collect::<Vec<_Candidate<AccountId>>>()
} else {
initial_candidates.into_iter()
.enumerate()
.map(|(idx, who)| {
c_idx_cache.insert(who.clone(), idx);
_Candidate { who, ..Default::default() }
})
.collect::<Vec<_Candidate<AccountId>>>()
};
if candidates.len() < minimum_candidate_count {
return None;
}
voters.extend(initial_voters.into_iter().map(|(who, votes)| {
let voter_stake = stake_of(&who) as f64;
let mut edges: Vec<_Edge<AccountId>> = Vec::with_capacity(votes.len());
for v in votes {
if let Some(idx) = c_idx_cache.get(&v) {
candidates[*idx].approval_stake = candidates[*idx].approval_stake + voter_stake;
edges.push(
_Edge { who: v.clone(), candidate_index: *idx, ..Default::default() }
);
}
}
_Voter {
who,
edges: edges,
budget: voter_stake,
load: 0f64,
}
}));
let to_elect = candidate_count.min(candidates.len());
elected_candidates = Vec::with_capacity(candidate_count);
assigned = Vec::with_capacity(candidate_count);
for _round in 0..to_elect {
for c in &mut candidates {
if !c.elected {
c.score = 1.0 / c.approval_stake;
}
}
for n in &voters {
for e in &n.edges {
let c = &mut candidates[e.candidate_index];
if !c.elected && !(c.approval_stake == 0f64) {
c.score += n.budget * n.load / c.approval_stake;
}
}
}
if let Some(winner) = candidates
.iter_mut()
.filter(|c| !c.elected)
.min_by(|x, y| x.score.partial_cmp(&y.score).unwrap_or(rstd::cmp::Ordering::Equal))
{
winner.elected = true;
for n in &mut voters {
for e in &mut n.edges {
if e.who == winner.who {
e.load = winner.score - n.load;
n.load = winner.score;
}
}
}
elected_candidates.push(winner.who.clone());
} else {
break
}
}
for n in &mut voters {
let mut assignment = (n.who.clone(), vec![]);
for e in &mut n.edges {
if let Some(c) = elected_candidates.iter().cloned().find(|c| *c == e.who) {
if c != n.who {
let ratio = e.load / n.load;
assignment.1.push((e.who.clone(), ratio));
}
}
}
assigned.push(assignment);
}
Some(_PhragmenResult {
winners: elected_candidates,
assignments: assigned,
})
}
#[test]
fn float_poc_works() {
let candidates = vec![1, 2, 3];
let voters = vec![
(10, vec![1, 2]),
(20, vec![1, 3]),
(30, vec![2, 3]),
];
let stake_of = |x: &u64| { if *x >= 10 { *x } else { 0 }};
let _PhragmenResult { winners, assignments } =
elect_poc(2, 2, candidates, voters, stake_of, false).unwrap();
assert_eq_uvec!(winners, vec![2, 3]);
assert_eq_uvec!(
assignments,
vec![
(10, vec![(2, 1.0)]),
(20, vec![(3, 1.0)]),
(30, vec![(2, 0.5), (3, 0.5)])
]
);
}
#[test]
fn phragmen_works() {
let candidates = vec![1, 2, 3];
let voters = vec![
(10, vec![1, 2]),
(20, vec![1, 3]),
(30, vec![2, 3]),
];
let stake_of = |x: &u64| { if *x >= 10 { *x } else { 0 }};
let PhragmenResult { winners, assignments } =
elect::<_, _, _, C>(2, 2, candidates, voters, stake_of, false).unwrap();
assert_eq_uvec!(winners, vec![2, 3]);
assert_eq_uvec!(
assignments,
vec![
(10, vec![(2, ACCURACY)]),
(20, vec![(3, ACCURACY)]),
(30, vec![(2, ACCURACY/2), (3, ACCURACY/2)])
]
);
}
}
+419
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@@ -0,0 +1,419 @@
// Copyright 2019 Parity Technologies (UK) Ltd.
// This file is part of Substrate.
// Substrate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Substrate is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Substrate. If not, see <http://www.gnu.org/licenses/>.
//! Mock file for phragmen.
#![cfg(test)]
use crate::{elect, ACCURACY, PhragmenResult};
use sr_primitives::traits::{Convert, Member, SaturatedConversion};
use rstd::collections::btree_map::BTreeMap;
use support::assert_eq_error_rate;
pub(crate) struct TestCurrencyToVote;
impl Convert<Balance, u64> for TestCurrencyToVote {
fn convert(x: Balance) -> u64 { x.saturated_into() }
}
impl Convert<u128, Balance> for TestCurrencyToVote {
fn convert(x: u128) -> Balance { x }
}
#[derive(Default, Debug)]
pub(crate) struct _Candidate<A> {
who: A,
score: f64,
approval_stake: f64,
elected: bool,
}
#[derive(Default, Debug)]
pub(crate) struct _Voter<A> {
who: A,
edges: Vec<_Edge<A>>,
budget: f64,
load: f64,
}
#[derive(Default, Debug)]
pub(crate) struct _Edge<A> {
who: A,
load: f64,
candidate_index: usize,
}
#[derive(Default, Debug, PartialEq)]
pub(crate) struct _Support<A> {
pub own: f64,
pub total: f64,
pub others: Vec<_PhragmenAssignment<A>>,
}
pub(crate) type _PhragmenAssignment<A> = (A, f64);
pub(crate) type _SupportMap<A> = BTreeMap<A, _Support<A>>;
pub(crate) type Balance = u128;
pub(crate) type AccountId = u64;
#[derive(Debug, Clone)]
pub(crate) struct _PhragmenResult<A: Clone> {
pub winners: Vec<A>,
pub assignments: Vec<(A, Vec<_PhragmenAssignment<A>>)>
}
pub(crate) fn elect_float<A, FS>(
candidate_count: usize,
minimum_candidate_count: usize,
initial_candidates: Vec<A>,
initial_voters: Vec<(A, Vec<A>)>,
stake_of: FS,
self_vote: bool,
) -> Option<_PhragmenResult<A>> where
A: Default + Ord + Member + Copy,
for<'r> FS: Fn(&'r A) -> Balance,
{
let mut elected_candidates: Vec<A>;
let mut assigned: Vec<(A, Vec<_PhragmenAssignment<A>>)>;
let mut c_idx_cache = BTreeMap::<A, usize>::new();
let num_voters = initial_candidates.len() + initial_voters.len();
let mut voters: Vec<_Voter<A>> = Vec::with_capacity(num_voters);
let mut candidates = if self_vote {
initial_candidates.into_iter().map(|who| {
let stake = stake_of(&who) as f64;
_Candidate { who, approval_stake: stake, ..Default::default() }
})
.filter(|c| c.approval_stake != 0f64)
.enumerate()
.map(|(i, c)| {
let who = c.who;
voters.push(_Voter {
who: who.clone(),
edges: vec![
_Edge { who: who.clone(), candidate_index: i, ..Default::default() }
],
budget: c.approval_stake,
load: 0f64,
});
c_idx_cache.insert(c.who.clone(), i);
c
})
.collect::<Vec<_Candidate<A>>>()
} else {
initial_candidates.into_iter()
.enumerate()
.map(|(idx, who)| {
c_idx_cache.insert(who.clone(), idx);
_Candidate { who, ..Default::default() }
})
.collect::<Vec<_Candidate<A>>>()
};
if candidates.len() < minimum_candidate_count {
return None;
}
voters.extend(initial_voters.into_iter().map(|(who, votes)| {
let voter_stake = stake_of(&who) as f64;
let mut edges: Vec<_Edge<A>> = Vec::with_capacity(votes.len());
for v in votes {
if let Some(idx) = c_idx_cache.get(&v) {
candidates[*idx].approval_stake = candidates[*idx].approval_stake + voter_stake;
edges.push(
_Edge { who: v.clone(), candidate_index: *idx, ..Default::default() }
);
}
}
_Voter {
who,
edges: edges,
budget: voter_stake,
load: 0f64,
}
}));
let to_elect = candidate_count.min(candidates.len());
elected_candidates = Vec::with_capacity(candidate_count);
assigned = Vec::with_capacity(candidate_count);
for _round in 0..to_elect {
for c in &mut candidates {
if !c.elected {
c.score = 1.0 / c.approval_stake;
}
}
for n in &voters {
for e in &n.edges {
let c = &mut candidates[e.candidate_index];
if !c.elected && !(c.approval_stake == 0f64) {
c.score += n.budget * n.load / c.approval_stake;
}
}
}
if let Some(winner) = candidates
.iter_mut()
.filter(|c| !c.elected)
.min_by(|x, y| x.score.partial_cmp(&y.score).unwrap_or(rstd::cmp::Ordering::Equal))
{
winner.elected = true;
for n in &mut voters {
for e in &mut n.edges {
if e.who == winner.who {
e.load = winner.score - n.load;
n.load = winner.score;
}
}
}
elected_candidates.push(winner.who.clone());
} else {
break
}
}
for n in &mut voters {
let mut assignment = (n.who.clone(), vec![]);
for e in &mut n.edges {
if let Some(c) = elected_candidates.iter().cloned().find(|c| *c == e.who) {
if c != n.who {
let ratio = e.load / n.load;
assignment.1.push((e.who.clone(), ratio));
}
}
}
if assignment.1.len() > 0 {
assigned.push(assignment);
}
}
Some(_PhragmenResult {
winners: elected_candidates,
assignments: assigned,
})
}
pub(crate) fn equalize_float<A, FS>(
mut assignments: Vec<(A, Vec<_PhragmenAssignment<A>>)>,
supports: &mut _SupportMap<A>,
tolerance: f64,
iterations: usize,
stake_of: FS,
) where
for<'r> FS: Fn(&'r A) -> Balance,
A: Ord + Clone + std::fmt::Debug,
{
for _i in 0..iterations {
let mut max_diff = 0.0;
for (voter, assignment) in assignments.iter_mut() {
let voter_budget = stake_of(&voter);
let diff = do_equalize_float(
voter,
voter_budget,
assignment,
supports,
tolerance,
);
if diff > max_diff { max_diff = diff; }
}
if max_diff < tolerance {
break;
}
}
}
pub(crate) fn do_equalize_float<A>(
voter: &A,
budget_balance: Balance,
elected_edges: &mut Vec<_PhragmenAssignment<A>>,
support_map: &mut _SupportMap<A>,
tolerance: f64
) -> f64 where
A: Ord + Clone,
{
let budget = budget_balance as f64;
if elected_edges.is_empty() { return 0.0; }
let stake_used = elected_edges
.iter()
.fold(0.0, |s, e| s + e.1);
let backed_stakes_iter = elected_edges
.iter()
.filter_map(|e| support_map.get(&e.0))
.map(|e| e.total);
let backing_backed_stake = elected_edges
.iter()
.filter(|e| e.1 > 0.0)
.filter_map(|e| support_map.get(&e.0))
.map(|e| e.total)
.collect::<Vec<f64>>();
let mut difference;
if backing_backed_stake.len() > 0 {
let max_stake = backing_backed_stake
.iter()
.max_by(|x, y| x.partial_cmp(&y).unwrap_or(rstd::cmp::Ordering::Equal))
.expect("vector with positive length will have a max; qed");
let min_stake = backed_stakes_iter
.min_by(|x, y| x.partial_cmp(&y).unwrap_or(rstd::cmp::Ordering::Equal))
.expect("iterator with positive length will have a min; qed");
difference = max_stake - min_stake;
difference = difference + budget - stake_used;
if difference < tolerance {
return difference;
}
} else {
difference = budget;
}
// Undo updates to support
elected_edges.iter_mut().for_each(|e| {
if let Some(support) = support_map.get_mut(&e.0) {
support.total = support.total - e.1;
support.others.retain(|i_support| i_support.0 != *voter);
}
e.1 = 0.0;
});
// todo: rewrite.
elected_edges.sort_unstable_by(|x, y|
if let Some(x) = support_map.get(&x.0) {
if let Some(y) = support_map.get(&y.0) {
x.total.partial_cmp(&y.total).unwrap_or(rstd::cmp::Ordering::Equal)
} else {
rstd::cmp::Ordering::Equal
}
} else {
rstd::cmp::Ordering::Equal
}
);
let mut cumulative_stake = 0.0;
let mut last_index = elected_edges.len() - 1;
elected_edges.iter_mut().enumerate().for_each(|(idx, e)| {
if let Some(support) = support_map.get_mut(&e.0) {
let stake = support.total;
let stake_mul = stake * (idx as f64);
let stake_sub = stake_mul - cumulative_stake;
if stake_sub > budget {
last_index = idx.checked_sub(1).unwrap_or(0);
return
}
cumulative_stake = cumulative_stake + stake;
}
});
let last_stake = elected_edges[last_index].1;
let split_ways = last_index + 1;
let excess = budget + cumulative_stake - last_stake * (split_ways as f64);
elected_edges.iter_mut().take(split_ways).for_each(|e| {
if let Some(support) = support_map.get_mut(&e.0) {
e.1 = excess / (split_ways as f64) + last_stake - support.total;
support.total = support.total + e.1;
support.others.push((voter.clone(), e.1));
}
});
difference
}
pub(crate) fn create_stake_of(stakes: &[(AccountId, Balance)])
-> Box<dyn Fn(&AccountId) -> Balance>
{
let mut storage = BTreeMap::<AccountId, Balance>::new();
stakes.iter().for_each(|s| { storage.insert(s.0, s.1); });
let stake_of = move |who: &AccountId| -> Balance { storage.get(who).unwrap().to_owned() };
Box::new(stake_of)
}
pub(crate) fn run_and_compare(
candidates: Vec<AccountId>,
voters: Vec<(AccountId, Vec<AccountId>)>,
stake_of: Box<dyn Fn(&AccountId) -> Balance>,
to_elect: usize,
min_to_elect: usize,
self_vote: bool,
) {
// run fixed point code.
let PhragmenResult { winners, assignments } = elect::<_, _, _, TestCurrencyToVote>(
to_elect,
min_to_elect,
candidates.clone(),
voters.clone(),
&stake_of,
self_vote,
).unwrap();
// run float poc code.
let truth_value = elect_float(
to_elect,
min_to_elect,
candidates,
voters,
&stake_of,
self_vote,
).unwrap();
assert_eq!(winners, truth_value.winners);
for (nominator, assigned) in assignments.clone() {
if let Some(float_assignments) = truth_value.assignments.iter().find(|x| x.0 == nominator) {
for (candidate, ratio) in assigned {
if let Some(float_assignment) = float_assignments.1.iter().find(|x| x.0 == candidate ) {
assert_eq_error_rate!((float_assignment.1 * ACCURACY as f64).round() as u128, ratio, 1);
} else {
panic!("candidate mismatch. This should never happen.")
}
}
} else {
panic!("nominator mismatch. This should never happen.")
}
}
}
pub(crate) fn build_support_map<FS>(
result: &mut _PhragmenResult<AccountId>,
stake_of: FS,
) -> _SupportMap<AccountId>
where for<'r> FS: Fn(&'r AccountId) -> Balance
{
let mut supports = <_SupportMap<AccountId>>::new();
result.winners
.iter()
.map(|e| (e, stake_of(e) as f64))
.for_each(|(e, s)| {
let item = _Support { own: s, total: s, ..Default::default() };
supports.insert(e.clone(), item);
});
for (n, assignment) in result.assignments.iter_mut() {
for (c, r) in assignment.iter_mut() {
let nominator_stake = stake_of(n) as f64;
let other_stake = nominator_stake * *r;
if let Some(support) = supports.get_mut(c) {
support.total = support.total + other_stake;
support.others.push((n.clone(), other_stake));
}
*r = other_stake;
}
}
supports
}
+135
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@@ -0,0 +1,135 @@
// Copyright 2019 Parity Technologies (UK) Ltd.
// This file is part of Substrate.
// Substrate is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Substrate is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Substrate. If not, see <http://www.gnu.org/licenses/>.
//! Tests for phragmen.
#![cfg(test)]
use crate::mock::*;
use crate::{elect, ACCURACY, PhragmenResult};
use support::assert_eq_uvec;
#[test]
fn float_phragmen_poc_works() {
let candidates = vec![1, 2, 3];
let voters = vec![
(10, vec![1, 2]),
(20, vec![1, 3]),
(30, vec![2, 3]),
];
let stake_of = create_stake_of(&[(10, 10), (20, 20), (30, 30), (1, 0), (2, 0), (3, 0)]);
let mut phragmen_result = elect_float(2, 2, candidates, voters, &stake_of, false).unwrap();
let winners = phragmen_result.clone().winners;
let assignments = phragmen_result.clone().assignments;
assert_eq_uvec!(winners, vec![2, 3]);
assert_eq_uvec!(
assignments,
vec![
(10, vec![(2, 1.0)]),
(20, vec![(3, 1.0)]),
(30, vec![(2, 0.5), (3, 0.5)]),
]
);
let mut support_map = build_support_map(&mut phragmen_result, &stake_of);
assert_eq!(
support_map.get(&2).unwrap(),
&_Support { own: 0.0, total: 25.0, others: vec![(10u64, 10.0), (30u64, 15.0)]}
);
assert_eq!(
support_map.get(&3).unwrap(),
&_Support { own: 0.0, total: 35.0, others: vec![(20u64, 20.0), (30u64, 15.0)]}
);
equalize_float(phragmen_result.assignments, &mut support_map, 0.0, 2, stake_of);
assert_eq!(
support_map.get(&2).unwrap(),
&_Support { own: 0.0, total: 30.0, others: vec![(10u64, 10.0), (30u64, 20.0)]}
);
assert_eq!(
support_map.get(&3).unwrap(),
&_Support { own: 0.0, total: 30.0, others: vec![(20u64, 20.0), (30u64, 10.0)]}
);
}
#[test]
fn phragmen_poc_works() {
let candidates = vec![1, 2, 3];
let voters = vec![
(10, vec![1, 2]),
(20, vec![1, 3]),
(30, vec![2, 3]),
];
let PhragmenResult { winners, assignments } = elect::<_, _, _, TestCurrencyToVote>(
2,
2,
candidates,
voters,
create_stake_of(&[(10, 10), (20, 20), (30, 30)]),
false,
).unwrap();
assert_eq_uvec!(winners, vec![2, 3]);
assert_eq_uvec!(
assignments,
vec![
(10, vec![(2, ACCURACY)]),
(20, vec![(3, ACCURACY)]),
(30, vec![(2, ACCURACY/2), (3, ACCURACY/2)]),
]
);
}
#[test]
fn phragmen_poc_2_works() {
let candidates = vec![10, 20, 30];
let voters = vec![
(2, vec![10, 20, 30]),
(4, vec![10, 20, 40]),
];
let stake_of = create_stake_of(&[
(10, 1000),
(20, 1000),
(30, 1000),
(40, 1000),
(2, 500),
(4, 500),
]);
run_and_compare(candidates, voters, stake_of, 2, 2, true);
}
#[test]
fn phragmen_poc_3_works() {
let candidates = vec![10, 20, 30];
let voters = vec![
(2, vec![10, 20, 30]),
(4, vec![10, 20, 40]),
];
let stake_of = create_stake_of(&[
(10, 1000),
(20, 1000),
(30, 1000),
(2, 50),
(4, 1000),
]);
run_and_compare(candidates, voters, stake_of, 2, 2, true);
}