Change the way new layout assignations are computed.
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The function now computes an optimal assignation (with respect to partition size) that minimizes the distance to the former assignation, using flow algorithms. This commit was written by Mendes Oulamara <mendes.oulamara@pm.me>
This commit is contained in:
parent
c9ef3e461b
commit
c1d1646c4d
4 changed files with 806 additions and 413 deletions
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@ -23,6 +23,7 @@ gethostname = "0.2"
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hex = "0.4"
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tracing = "0.1.30"
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rand = "0.8"
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itertools="0.10"
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sodiumoxide = { version = "0.2.5-0", package = "kuska-sodiumoxide" }
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async-trait = "0.1.7"
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@ -1,10 +1,14 @@
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use std::cmp::Ordering;
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use std::collections::{HashMap, HashSet};
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use std::cmp::{min};
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use std::collections::{HashMap};
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use serde::{Deserialize, Serialize};
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use garage_util::crdt::{AutoCrdt, Crdt, LwwMap};
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use garage_util::data::*;
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use garage_util::bipartite::*;
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use rand::prelude::SliceRandom;
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use crate::ring::*;
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@ -164,445 +168,454 @@ impl ClusterLayout {
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true
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}
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/// Calculate an assignation of partitions to nodes
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pub fn calculate_partition_assignation(&mut self) -> bool {
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let (configured_nodes, zones) = self.configured_nodes_and_zones();
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let n_zones = zones.len();
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println!("Calculating updated partition assignation, this may take some time...");
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println!();
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/// This function calculates a new partition-to-node assignation.
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/// The computed assignation maximizes the capacity of a
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/// partition (assuming all partitions have the same size).
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/// Among such optimal assignation, it minimizes the distance to
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/// the former assignation (if any) to minimize the amount of
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/// data to be moved. A heuristic ensures node triplets
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/// dispersion (in garage_util::bipartite::optimize_matching()).
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pub fn calculate_partition_assignation(&mut self) -> bool {
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// Get old partition assignation
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let old_partitions = self.parse_assignation_data();
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//The nodes might have been updated, some might have been deleted.
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//So we need to first update the list of nodes and retrieve the
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//assignation.
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let old_node_assignation = self.update_nodes_and_ring();
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// Start new partition assignation with nodes from old assignation where it is relevant
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let mut partitions = old_partitions
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.iter()
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.map(|old_part| {
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let mut new_part = PartitionAss::new();
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for node in old_part.nodes.iter() {
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if let Some(role) = node.1 {
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if role.capacity.is_some() {
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new_part.add(None, n_zones, node.0, role);
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}
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}
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}
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new_part
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})
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.collect::<Vec<_>>();
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let (node_zone, _) = self.get_node_zone_capacity();
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// In various cases, not enough nodes will have been added for all partitions
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// in the step above (e.g. due to node removals, or new zones being added).
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// Here we add more nodes to make a complete (but sub-optimal) assignation,
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// using an initial partition assignation that is calculated using the multi-dc maglev trick
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match self.initial_partition_assignation() {
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Some(initial_partitions) => {
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for (part, ipart) in partitions.iter_mut().zip(initial_partitions.iter()) {
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for (id, info) in ipart.nodes.iter() {
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if part.nodes.len() < self.replication_factor {
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part.add(None, n_zones, id, info.unwrap());
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}
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}
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assert!(part.nodes.len() == self.replication_factor);
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}
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}
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None => {
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// Not enough nodes in cluster to build a correct assignation.
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// Signal it by returning an error.
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return false;
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}
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}
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//We compute the optimal number of partition to assign to
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//every node and zone.
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if let Some((part_per_nod, part_per_zone)) = self.optimal_proportions(){
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//We collect part_per_zone in a vec to not rely on the
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//arbitrary order in which elements are iterated in
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//Hashmap::iter()
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let part_per_zone_vec = part_per_zone.iter()
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.map(|(x,y)| (x.clone(),*y))
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.collect::<Vec<(String,usize)>>();
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//We create an indexing of the zones
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let mut zone_id = HashMap::<String,usize>::new();
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for i in 0..part_per_zone_vec.len(){
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zone_id.insert(part_per_zone_vec[i].0.clone(), i);
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}
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// Calculate how many partitions each node should ideally store,
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// and how many partitions they are storing with the current assignation
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// This defines our target for which we will optimize in the following loop.
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let total_capacity = configured_nodes
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.iter()
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.map(|(_, info)| info.capacity.unwrap_or(0))
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.sum::<u32>() as usize;
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let total_partitions = self.replication_factor * (1 << PARTITION_BITS);
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let target_partitions_per_node = configured_nodes
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.iter()
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.map(|(id, info)| {
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(
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*id,
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info.capacity.unwrap_or(0) as usize * total_partitions / total_capacity,
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)
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})
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.collect::<HashMap<&Uuid, usize>>();
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//We compute a candidate for the new partition to zone
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//assignation.
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let nb_zones = part_per_zone.len();
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let nb_nodes = part_per_nod.len();
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let nb_partitions = 1<<PARTITION_BITS;
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let left_cap_vec = vec![self.replication_factor as u32 ; nb_partitions];
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let right_cap_vec = part_per_zone_vec.iter().map(|(_,y)| *y as u32)
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.collect();
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let mut zone_assignation =
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dinic_compute_matching(left_cap_vec, right_cap_vec);
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let mut partitions_per_node = self.partitions_per_node(&partitions[..]);
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println!("Target number of partitions per node:");
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for (node, npart) in target_partitions_per_node.iter() {
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println!("{:?}\t{}", node, npart);
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}
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println!();
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//We create the structure for the partition-to-node assignation.
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let mut node_assignation =
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vec![vec![None; self.replication_factor ];nb_partitions];
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//We will decrement part_per_nod to keep track of the number
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//of partitions that we still have to associate.
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let mut part_per_nod = part_per_nod.clone();
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// Shuffle partitions between nodes so that nodes will reach (or better approach)
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// their target number of stored partitions
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loop {
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let mut option = None;
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for (i, part) in partitions.iter_mut().enumerate() {
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for (irm, (idrm, _)) in part.nodes.iter().enumerate() {
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let errratio = |node, parts| {
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let tgt = *target_partitions_per_node.get(node).unwrap() as f32;
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(parts - tgt) / tgt
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};
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let square = |x| x * x;
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//We minimize the distance to the former assignation(if any)
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let partsrm = partitions_per_node.get(*idrm).cloned().unwrap_or(0) as f32;
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//We get the id of the zones of the former assignation
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//(and the id no_zone if there is no node assignated)
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let no_zone = part_per_zone_vec.len();
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let old_zone_assignation : Vec<Vec<usize>> =
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old_node_assignation.iter().map(|x| x.iter().map(
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|id| match *id { Some(i) => zone_id[&node_zone[i]] ,
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None => no_zone }
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).collect()).collect();
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for (idadd, infoadd) in configured_nodes.iter() {
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// skip replacing a node by itself
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// and skip replacing by gateway nodes
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if idadd == idrm || infoadd.capacity.is_none() {
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continue;
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}
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//We minimize the distance to the former zone assignation
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zone_assignation = optimize_matching(
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&old_zone_assignation, &zone_assignation, nb_zones+1); //+1 for no_zone
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// We want to try replacing node idrm by node idadd
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// if that brings us close to our goal.
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let partsadd = partitions_per_node.get(*idadd).cloned().unwrap_or(0) as f32;
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let oldcost = square(errratio(*idrm, partsrm) - errratio(*idadd, partsadd));
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let newcost =
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square(errratio(*idrm, partsrm - 1.) - errratio(*idadd, partsadd + 1.));
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if newcost >= oldcost {
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// not closer to our goal
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continue;
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}
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let gain = oldcost - newcost;
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//We need to assign partitions to nodes in their zone
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//We first put the nodes assignation that can stay the same
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for i in 0..nb_partitions{
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for j in 0..self.replication_factor {
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if let Some(Some(former_node)) = old_node_assignation[i].iter().find(
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|x| if let Some(id) = x {
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zone_id[&node_zone[*id]] == zone_assignation[i][j]
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}
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else {false}
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)
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{
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if part_per_nod[*former_node] > 0 {
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node_assignation[i][j] = Some(*former_node);
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part_per_nod[*former_node] -= 1;
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}
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}
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}
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}
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let mut newpart = part.clone();
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newpart.nodes.remove(irm);
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if !newpart.add(None, n_zones, idadd, infoadd) {
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continue;
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}
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assert!(newpart.nodes.len() == self.replication_factor);
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//We complete the assignation of partitions to nodes
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let mut rng = rand::thread_rng();
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for i in 0..nb_partitions {
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for j in 0..self.replication_factor {
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if node_assignation[i][j] == None {
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let possible_nodes : Vec<usize> = (0..nb_nodes)
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.filter(
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|id| zone_id[&node_zone[*id]] == zone_assignation[i][j]
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&& part_per_nod[*id] > 0).collect();
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assert!(possible_nodes.len()>0);
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//We randomly pick a node
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if let Some(nod) = possible_nodes.choose(&mut rng){
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node_assignation[i][j] = Some(*nod);
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part_per_nod[*nod] -= 1;
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}
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}
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}
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}
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if !old_partitions[i]
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.is_valid_transition_to(&newpart, self.replication_factor)
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{
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continue;
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}
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//We write the assignation in the 1D table
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self.ring_assignation_data = Vec::<CompactNodeType>::new();
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for i in 0..nb_partitions{
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for j in 0..self.replication_factor {
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if let Some(id) = node_assignation[i][j] {
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self.ring_assignation_data.push(id as CompactNodeType);
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}
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else {assert!(false)}
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}
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}
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if option
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.as_ref()
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.map(|(old_gain, _, _, _, _)| gain > *old_gain)
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.unwrap_or(true)
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{
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option = Some((gain, i, idadd, idrm, newpart));
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}
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}
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}
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}
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if let Some((_gain, i, idadd, idrm, newpart)) = option {
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*partitions_per_node.entry(idadd).or_insert(0) += 1;
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*partitions_per_node.get_mut(idrm).unwrap() -= 1;
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partitions[i] = newpart;
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} else {
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break;
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}
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}
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true
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}
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else { false }
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}
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// Check we completed the assignation correctly
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// (this is a set of checks for the algorithm's consistency)
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assert!(partitions.len() == (1 << PARTITION_BITS));
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assert!(partitions
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.iter()
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.all(|p| p.nodes.len() == self.replication_factor));
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/// The LwwMap of node roles might have changed. This function updates the node_id_vec
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/// and returns the assignation given by ring, with the new indices of the nodes, and
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/// None of the node is not present anymore.
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/// We work with the assumption that only this function and calculate_new_assignation
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/// do modify assignation_ring and node_id_vec.
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fn update_nodes_and_ring(&mut self) -> Vec<Vec<Option<usize>>> {
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let nb_partitions = 1usize<<PARTITION_BITS;
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let mut node_assignation =
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vec![vec![None; self.replication_factor ];nb_partitions];
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let rf = self.replication_factor;
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let ring = &self.ring_assignation_data;
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let new_partitions_per_node = self.partitions_per_node(&partitions[..]);
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assert!(new_partitions_per_node == partitions_per_node);
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let new_node_id_vec : Vec::<Uuid> = self.roles.items().iter()
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.map(|(k, _, _)| *k)
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.collect();
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// Show statistics
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println!("New number of partitions per node:");
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for (node, npart) in partitions_per_node.iter() {
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let tgt = *target_partitions_per_node.get(node).unwrap();
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let pct = 100f32 * (*npart as f32) / (tgt as f32);
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println!("{:?}\t{}\t({}% of {})", node, npart, pct as i32, tgt);
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}
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println!();
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if ring.len() == rf*nb_partitions {
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for i in 0..nb_partitions {
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for j in 0..self.replication_factor {
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node_assignation[i][j] = new_node_id_vec.iter()
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.position(|id| *id == self.node_id_vec[ring[i*rf + j] as usize]);
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}
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}
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}
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let mut diffcount = HashMap::new();
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for (oldpart, newpart) in old_partitions.iter().zip(partitions.iter()) {
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let nminus = oldpart.txtplus(newpart);
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let nplus = newpart.txtplus(oldpart);
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if nminus != "[...]" || nplus != "[...]" {
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let tup = (nminus, nplus);
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*diffcount.entry(tup).or_insert(0) += 1;
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}
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}
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if diffcount.is_empty() {
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println!("No data will be moved between nodes.");
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} else {
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let mut diffcount = diffcount.into_iter().collect::<Vec<_>>();
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diffcount.sort();
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println!("Number of partitions that move:");
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for ((nminus, nplus), npart) in diffcount {
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println!("\t{}\t{} -> {}", npart, nminus, nplus);
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}
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}
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println!();
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self.node_id_vec = new_node_id_vec;
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self.ring_assignation_data = vec![];
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return node_assignation;
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}
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// Calculate and save new assignation data
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let (nodes, assignation_data) =
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self.compute_assignation_data(&configured_nodes[..], &partitions[..]);
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///This function compute the number of partition to assign to
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///every node and zone, so that every partition is replicated
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///self.replication_factor times and the capacity of a partition
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///is maximized.
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fn optimal_proportions(&mut self) -> Option<(Vec<usize>, HashMap<String, usize>)> {
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self.node_id_vec = nodes;
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self.ring_assignation_data = assignation_data;
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let mut zone_capacity :HashMap<String, u32>= HashMap::new();
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true
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}
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let (node_zone, node_capacity) = self.get_node_zone_capacity();
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let nb_nodes = self.node_id_vec.len();
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fn initial_partition_assignation(&self) -> Option<Vec<PartitionAss<'_>>> {
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let (configured_nodes, zones) = self.configured_nodes_and_zones();
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let n_zones = zones.len();
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for i in 0..nb_nodes
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{
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if zone_capacity.contains_key(&node_zone[i]) {
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zone_capacity.insert(node_zone[i].clone(), zone_capacity[&node_zone[i]] + node_capacity[i]);
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}
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else{
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zone_capacity.insert(node_zone[i].clone(), node_capacity[i]);
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}
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}
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// Create a vector of partition indices (0 to 2**PARTITION_BITS-1)
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let partitions_idx = (0usize..(1usize << PARTITION_BITS)).collect::<Vec<_>>();
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//Compute the optimal number of partitions per zone
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let sum_capacities: u32 =zone_capacity.values().sum();
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// Prepare ring
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let mut partitions: Vec<PartitionAss> = partitions_idx
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.iter()
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.map(|_i| PartitionAss::new())
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.collect::<Vec<_>>();
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if sum_capacities <= 0 {
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println!("No storage capacity in the network.");
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return None;
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}
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// Create MagLev priority queues for each node
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let mut queues = configured_nodes
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.iter()
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.filter(|(_id, info)| info.capacity.is_some())
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.map(|(node_id, node_info)| {
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let mut parts = partitions_idx
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.iter()
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.map(|i| {
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let part_data =
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[&u16::to_be_bytes(*i as u16)[..], node_id.as_slice()].concat();
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(*i, fasthash(&part_data[..]))
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})
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.collect::<Vec<_>>();
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parts.sort_by_key(|(_i, h)| *h);
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let parts_i = parts.iter().map(|(i, _h)| *i).collect::<Vec<_>>();
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(node_id, node_info, parts_i, 0)
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})
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.collect::<Vec<_>>();
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let nb_partitions = 1<<PARTITION_BITS;
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let max_capacity = configured_nodes
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.iter()
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.filter_map(|(_, node_info)| node_info.capacity)
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.fold(0, std::cmp::max);
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//Initially we would like to use zones porportionally to
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//their capacity.
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//However, a large zone can be associated to at most
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//nb_partitions to ensure replication of the date.
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//So we take the min with nb_partitions:
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let mut part_per_zone : HashMap<String, usize> =
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zone_capacity.iter()
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.map(|(k, v)| (k.clone(), min(nb_partitions,
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(self.replication_factor*nb_partitions
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**v as usize)/sum_capacities as usize) ) ).collect();
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// Fill up ring
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for rep in 0..self.replication_factor {
|
||||
queues.sort_by_key(|(ni, _np, _q, _p)| {
|
||||
let queue_data = [&u16::to_be_bytes(rep as u16)[..], ni.as_slice()].concat();
|
||||
fasthash(&queue_data[..])
|
||||
});
|
||||
//The replication_factor-1 upper bounds the number of
|
||||
//part_per_zones that are greater than nb_partitions
|
||||
for _ in 1..self.replication_factor {
|
||||
//The number of partitions that are not assignated to
|
||||
//a zone that takes nb_partitions.
|
||||
let sum_capleft : u32 = zone_capacity.keys()
|
||||
.filter(| k | {part_per_zone[*k] < nb_partitions} )
|
||||
.map(|k| zone_capacity[k]).sum();
|
||||
|
||||
for (_, _, _, pos) in queues.iter_mut() {
|
||||
*pos = 0;
|
||||
}
|
||||
//The number of replication of the data that we need
|
||||
//to ensure.
|
||||
let repl_left = self.replication_factor
|
||||
- part_per_zone.values()
|
||||
.filter(|x| {**x == nb_partitions})
|
||||
.count();
|
||||
if repl_left == 0 {
|
||||
break;
|
||||
}
|
||||
|
||||
let mut remaining = partitions_idx.len();
|
||||
while remaining > 0 {
|
||||
let remaining0 = remaining;
|
||||
for i_round in 0..max_capacity {
|
||||
for (node_id, node_info, q, pos) in queues.iter_mut() {
|
||||
if i_round >= node_info.capacity.unwrap() {
|
||||
continue;
|
||||
}
|
||||
for (pos2, &qv) in q.iter().enumerate().skip(*pos) {
|
||||
if partitions[qv].add(Some(rep + 1), n_zones, node_id, node_info) {
|
||||
remaining -= 1;
|
||||
*pos = pos2 + 1;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
if remaining == remaining0 {
|
||||
// No progress made, exit
|
||||
return None;
|
||||
}
|
||||
}
|
||||
}
|
||||
for k in zone_capacity.keys() {
|
||||
if part_per_zone[k] != nb_partitions
|
||||
{
|
||||
part_per_zone.insert(k.to_string() , min(nb_partitions,
|
||||
(nb_partitions*zone_capacity[k] as usize
|
||||
*repl_left)/sum_capleft as usize));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Some(partitions)
|
||||
}
|
||||
//Now we divide the zone's partition share proportionally
|
||||
//between their nodes.
|
||||
|
||||
fn configured_nodes_and_zones(&self) -> (Vec<(&Uuid, &NodeRole)>, HashSet<&str>) {
|
||||
let configured_nodes = self
|
||||
.roles
|
||||
.items()
|
||||
.iter()
|
||||
.filter(|(_id, _, info)| info.0.is_some())
|
||||
.map(|(id, _, info)| (id, info.0.as_ref().unwrap()))
|
||||
.collect::<Vec<(&Uuid, &NodeRole)>>();
|
||||
let mut part_per_nod : Vec<usize> = (0..nb_nodes).map(
|
||||
|i| (part_per_zone[&node_zone[i]]*node_capacity[i] as usize)/zone_capacity[&node_zone[i]] as usize
|
||||
)
|
||||
.collect();
|
||||
|
||||
let zones = configured_nodes
|
||||
.iter()
|
||||
.filter(|(_id, info)| info.capacity.is_some())
|
||||
.map(|(_id, info)| info.zone.as_str())
|
||||
.collect::<HashSet<&str>>();
|
||||
//We must update the part_per_zone to make it correspond to
|
||||
//part_per_nod (because of integer rounding)
|
||||
part_per_zone = part_per_zone.iter().map(|(k,_)|
|
||||
(k.clone(), 0))
|
||||
.collect();
|
||||
for i in 0..nb_nodes {
|
||||
part_per_zone.insert(
|
||||
node_zone[i].clone() ,
|
||||
part_per_zone[&node_zone[i]] + part_per_nod[i]);
|
||||
}
|
||||
|
||||
(configured_nodes, zones)
|
||||
}
|
||||
//Because of integer rounding, the total sum of part_per_nod
|
||||
//might not be replication_factor*nb_partitions.
|
||||
// We need at most to add 1 to every non maximal value of
|
||||
// part_per_nod. The capacity of a partition will be bounded
|
||||
// by the minimal value of
|
||||
// node_capacity_vec[i]/part_per_nod[i]
|
||||
// so we try to maximize this minimal value, keeping the
|
||||
// part_per_zone capped
|
||||
|
||||
fn compute_assignation_data<'a>(
|
||||
&self,
|
||||
configured_nodes: &[(&'a Uuid, &'a NodeRole)],
|
||||
partitions: &[PartitionAss<'a>],
|
||||
) -> (Vec<Uuid>, Vec<CompactNodeType>) {
|
||||
assert!(partitions.len() == (1 << PARTITION_BITS));
|
||||
let discrepancy : usize =
|
||||
nb_partitions*self.replication_factor
|
||||
- part_per_nod.iter().sum::<usize>();
|
||||
|
||||
// Make a canonical order for nodes
|
||||
let mut nodes = configured_nodes
|
||||
.iter()
|
||||
.filter(|(_id, info)| info.capacity.is_some())
|
||||
.map(|(id, _)| **id)
|
||||
.collect::<Vec<_>>();
|
||||
let nodes_rev = nodes
|
||||
.iter()
|
||||
.enumerate()
|
||||
.map(|(i, id)| (*id, i as CompactNodeType))
|
||||
.collect::<HashMap<Uuid, CompactNodeType>>();
|
||||
//We use a stupid O(N^2) algorithm. If the number of nodes
|
||||
//is actually expected to be high, one should optimize this.
|
||||
|
||||
let mut assignation_data = vec![];
|
||||
for partition in partitions.iter() {
|
||||
assert!(partition.nodes.len() == self.replication_factor);
|
||||
for (id, _) in partition.nodes.iter() {
|
||||
assignation_data.push(*nodes_rev.get(id).unwrap());
|
||||
}
|
||||
}
|
||||
for _ in 0..discrepancy {
|
||||
if let Some(idmax) = (0..nb_nodes)
|
||||
.filter(|i| part_per_zone[&node_zone[*i]] < nb_partitions)
|
||||
.max_by( |i,j|
|
||||
(node_capacity[*i]*(part_per_nod[*j]+1) as u32)
|
||||
.cmp(&(node_capacity[*j]*(part_per_nod[*i]+1) as u32))
|
||||
)
|
||||
{
|
||||
part_per_nod[idmax] += 1;
|
||||
part_per_zone.insert(node_zone[idmax].clone(),part_per_zone[&node_zone[idmax]]+1);
|
||||
}
|
||||
}
|
||||
|
||||
nodes.extend(
|
||||
configured_nodes
|
||||
.iter()
|
||||
.filter(|(_id, info)| info.capacity.is_none())
|
||||
.map(|(id, _)| **id),
|
||||
);
|
||||
//We check the algorithm consistency
|
||||
|
||||
(nodes, assignation_data)
|
||||
}
|
||||
let discrepancy : usize =
|
||||
nb_partitions*self.replication_factor
|
||||
- part_per_nod.iter().sum::<usize>();
|
||||
assert!(discrepancy == 0);
|
||||
assert!(if let Some(v) = part_per_zone.values().max()
|
||||
{*v <= nb_partitions} else {false} );
|
||||
|
||||
fn parse_assignation_data(&self) -> Vec<PartitionAss<'_>> {
|
||||
if self.ring_assignation_data.len() == self.replication_factor * (1 << PARTITION_BITS) {
|
||||
// If the previous assignation data is correct, use that
|
||||
let mut partitions = vec![];
|
||||
for i in 0..(1 << PARTITION_BITS) {
|
||||
let mut part = PartitionAss::new();
|
||||
for node_i in self.ring_assignation_data
|
||||
[i * self.replication_factor..(i + 1) * self.replication_factor]
|
||||
.iter()
|
||||
{
|
||||
let node_id = &self.node_id_vec[*node_i as usize];
|
||||
Some((part_per_nod, part_per_zone))
|
||||
}
|
||||
|
||||
if let Some(NodeRoleV(Some(info))) = self.roles.get(node_id) {
|
||||
part.nodes.push((node_id, Some(info)));
|
||||
} else {
|
||||
part.nodes.push((node_id, None));
|
||||
}
|
||||
}
|
||||
partitions.push(part);
|
||||
}
|
||||
partitions
|
||||
} else {
|
||||
// Otherwise start fresh
|
||||
(0..(1 << PARTITION_BITS))
|
||||
.map(|_| PartitionAss::new())
|
||||
.collect()
|
||||
}
|
||||
}
|
||||
|
||||
fn partitions_per_node<'a>(&self, partitions: &[PartitionAss<'a>]) -> HashMap<&'a Uuid, usize> {
|
||||
let mut partitions_per_node = HashMap::<&Uuid, usize>::new();
|
||||
for p in partitions.iter() {
|
||||
for (id, _) in p.nodes.iter() {
|
||||
*partitions_per_node.entry(*id).or_insert(0) += 1;
|
||||
}
|
||||
}
|
||||
partitions_per_node
|
||||
}
|
||||
//Returns vectors of zone and capacity; indexed by the same (temporary)
|
||||
//indices as node_id_vec.
|
||||
fn get_node_zone_capacity(& self) -> (Vec<String> , Vec<u32>) {
|
||||
|
||||
let node_zone = self.node_id_vec.iter().map(
|
||||
|id_nod| match self.node_role(id_nod) {
|
||||
Some(NodeRole{zone,capacity:_,tags:_}) => zone.clone() ,
|
||||
_ => "".to_string()
|
||||
}
|
||||
).collect();
|
||||
|
||||
let node_capacity = self.node_id_vec.iter().map(
|
||||
|id_nod| match self.node_role(id_nod) {
|
||||
Some(NodeRole{zone:_,capacity,tags:_}) =>
|
||||
if let Some(c)=capacity
|
||||
{*c}
|
||||
else {0},
|
||||
_ => 0
|
||||
}
|
||||
).collect();
|
||||
|
||||
(node_zone,node_capacity)
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
// ---- Internal structs for partition assignation in layout ----
|
||||
|
||||
#[derive(Clone)]
|
||||
struct PartitionAss<'a> {
|
||||
nodes: Vec<(&'a Uuid, Option<&'a NodeRole>)>,
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
use itertools::Itertools;
|
||||
|
||||
fn check_assignation(cl : &ClusterLayout) {
|
||||
|
||||
//Check that input data has the right format
|
||||
let nb_partitions = 1usize<<PARTITION_BITS;
|
||||
assert!([1,2,3].contains(&cl.replication_factor));
|
||||
assert!(cl.ring_assignation_data.len() == nb_partitions*cl.replication_factor);
|
||||
|
||||
let (node_zone, node_capacity) = cl.get_node_zone_capacity();
|
||||
|
||||
|
||||
//Check that is is a correct assignation with zone redundancy
|
||||
let rf = cl.replication_factor;
|
||||
for i in 0..nb_partitions{
|
||||
assert!( rf ==
|
||||
cl.ring_assignation_data[rf*i..rf*(i+1)].iter()
|
||||
.map(|nod| node_zone[*nod as usize].clone())
|
||||
.unique()
|
||||
.count() );
|
||||
}
|
||||
|
||||
let nb_nodes = cl.node_id_vec.len();
|
||||
//Check optimality
|
||||
let node_nb_part =(0..nb_nodes).map(|i| cl.ring_assignation_data
|
||||
.iter()
|
||||
.filter(|x| **x==i as u8)
|
||||
.count())
|
||||
.collect::<Vec::<_>>();
|
||||
|
||||
let zone_vec = node_zone.iter().unique().collect::<Vec::<_>>();
|
||||
let zone_nb_part = zone_vec.iter().map( |z| cl.ring_assignation_data.iter()
|
||||
.filter(|x| node_zone[**x as usize] == **z)
|
||||
.count()
|
||||
).collect::<Vec::<_>>();
|
||||
|
||||
//Check optimality of the zone assignation : would it be better for the
|
||||
//node_capacity/node_partitions ratio to change the assignation of a partition
|
||||
|
||||
if let Some(idmin) = (0..nb_nodes).min_by(
|
||||
|i,j| (node_capacity[*i]*node_nb_part[*j] as u32)
|
||||
.cmp(&(node_capacity[*j]*node_nb_part[*i] as u32))
|
||||
){
|
||||
if let Some(idnew) = (0..nb_nodes)
|
||||
.filter( |i| if let Some(p) = zone_vec.iter().position(|z| **z==node_zone[*i])
|
||||
{zone_nb_part[p] < nb_partitions }
|
||||
else { false })
|
||||
.max_by(
|
||||
|i,j| (node_capacity[*i]*(node_nb_part[*j]as u32+1))
|
||||
.cmp(&(node_capacity[*j]*(node_nb_part[*i] as u32+1)))
|
||||
){
|
||||
assert!(node_capacity[idmin]*(node_nb_part[idnew] as u32+1) >=
|
||||
node_capacity[idnew]*node_nb_part[idmin] as u32);
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
//In every zone, check optimality of the nod assignation
|
||||
for z in zone_vec {
|
||||
let node_of_z_iter = (0..nb_nodes).filter(|id| node_zone[*id] == *z );
|
||||
if let Some(idmin) = node_of_z_iter.clone().min_by(
|
||||
|i,j| (node_capacity[*i]*node_nb_part[*j] as u32)
|
||||
.cmp(&(node_capacity[*j]*node_nb_part[*i] as u32))
|
||||
){
|
||||
if let Some(idnew) = node_of_z_iter.min_by(
|
||||
|i,j| (node_capacity[*i]*(node_nb_part[*j] as u32+1))
|
||||
.cmp(&(node_capacity[*j]*(node_nb_part[*i] as u32+1)))
|
||||
){
|
||||
assert!(node_capacity[idmin]*(node_nb_part[idnew] as u32+1) >=
|
||||
node_capacity[idnew]*node_nb_part[idmin] as u32);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
fn update_layout(cl : &mut ClusterLayout, node_id_vec : &Vec<u8>,
|
||||
node_capacity_vec : &Vec<u32> , node_zone_vec : &Vec<String>) {
|
||||
for i in 0..node_id_vec.len(){
|
||||
if let Some(x) = FixedBytes32::try_from(&[i as u8;32]) {
|
||||
cl.node_id_vec.push(x);
|
||||
}
|
||||
|
||||
let update = cl.roles.update_mutator(cl.node_id_vec[i] ,
|
||||
NodeRoleV(Some(NodeRole{
|
||||
zone : (node_zone_vec[i].to_string()),
|
||||
capacity : (Some(node_capacity_vec[i])),
|
||||
tags : (vec![])})));
|
||||
cl.roles.merge(&update);
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn test_assignation() {
|
||||
|
||||
let mut node_id_vec = vec![1,2,3];
|
||||
let mut node_capacity_vec = vec![4000,1000,2000];
|
||||
let mut node_zone_vec= vec!["A", "B", "C"].into_iter().map(|x| x.to_string()).collect();
|
||||
|
||||
let mut cl = ClusterLayout {
|
||||
node_id_vec: vec![],
|
||||
|
||||
roles : LwwMap::new(),
|
||||
|
||||
replication_factor: 3,
|
||||
ring_assignation_data : vec![],
|
||||
version:0,
|
||||
staging: LwwMap::new(),
|
||||
staging_hash: sha256sum(&[1;32]),
|
||||
};
|
||||
update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec);
|
||||
cl.calculate_partition_assignation();
|
||||
check_assignation(&cl);
|
||||
|
||||
node_id_vec = vec![1,2,3, 4, 5, 6, 7, 8, 9];
|
||||
node_capacity_vec = vec![4000,1000,1000, 3000, 1000, 1000, 2000, 10000, 2000];
|
||||
node_zone_vec= vec!["A", "B", "C", "C", "C", "B", "G", "H", "I"].into_iter().map(|x| x.to_string()).collect();
|
||||
update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec);
|
||||
cl.calculate_partition_assignation();
|
||||
check_assignation(&cl);
|
||||
|
||||
node_capacity_vec = vec![4000,1000,2000, 7000, 1000, 1000, 2000, 10000, 2000];
|
||||
update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec);
|
||||
cl.calculate_partition_assignation();
|
||||
check_assignation(&cl);
|
||||
|
||||
|
||||
node_capacity_vec = vec![4000,4000,2000, 7000, 1000, 9000, 2000, 10, 2000];
|
||||
update_layout(&mut cl, &node_id_vec, &node_capacity_vec, &node_zone_vec);
|
||||
cl.calculate_partition_assignation();
|
||||
check_assignation(&cl);
|
||||
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a> PartitionAss<'a> {
|
||||
fn new() -> Self {
|
||||
Self { nodes: Vec::new() }
|
||||
}
|
||||
|
||||
fn nplus(&self, other: &PartitionAss<'a>) -> usize {
|
||||
self.nodes
|
||||
.iter()
|
||||
.filter(|x| !other.nodes.contains(x))
|
||||
.count()
|
||||
}
|
||||
|
||||
fn txtplus(&self, other: &PartitionAss<'a>) -> String {
|
||||
let mut nodes = self
|
||||
.nodes
|
||||
.iter()
|
||||
.filter(|x| !other.nodes.contains(x))
|
||||
.map(|x| format!("{:?}", x.0))
|
||||
.collect::<Vec<_>>();
|
||||
nodes.sort();
|
||||
if self.nodes.iter().any(|x| other.nodes.contains(x)) {
|
||||
nodes.push("...".into());
|
||||
}
|
||||
format!("[{}]", nodes.join(" "))
|
||||
}
|
||||
|
||||
fn is_valid_transition_to(&self, other: &PartitionAss<'a>, replication_factor: usize) -> bool {
|
||||
let min_keep_nodes_per_part = (replication_factor + 1) / 2;
|
||||
let n_removed = self.nplus(other);
|
||||
|
||||
if self.nodes.len() <= min_keep_nodes_per_part {
|
||||
n_removed == 0
|
||||
} else {
|
||||
n_removed <= self.nodes.len() - min_keep_nodes_per_part
|
||||
}
|
||||
}
|
||||
|
||||
// add is a key function in creating a PartitionAss, i.e. the list of nodes
|
||||
// to which a partition is assigned. It tries to add a certain node id to the
|
||||
// assignation, but checks that doing so is compatible with the NECESSARY
|
||||
// condition that the partition assignation must be dispersed over different
|
||||
// zones (datacenters) if enough zones exist. This is why it takes a n_zones
|
||||
// parameter, which is the total number of zones that have existing nodes:
|
||||
// if nodes in the assignation already cover all n_zones zones, then any node
|
||||
// that is not yet in the assignation can be added. Otherwise, only nodes
|
||||
// that are in a new zone can be added.
|
||||
fn add(
|
||||
&mut self,
|
||||
target_len: Option<usize>,
|
||||
n_zones: usize,
|
||||
node: &'a Uuid,
|
||||
role: &'a NodeRole,
|
||||
) -> bool {
|
||||
if let Some(tl) = target_len {
|
||||
if self.nodes.len() != tl - 1 {
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
let p_zns = self
|
||||
.nodes
|
||||
.iter()
|
||||
.map(|(_id, info)| info.unwrap().zone.as_str())
|
||||
.collect::<HashSet<&str>>();
|
||||
if (p_zns.len() < n_zones && !p_zns.contains(&role.zone.as_str()))
|
||||
|| (p_zns.len() == n_zones && !self.nodes.iter().any(|(id, _)| *id == node))
|
||||
{
|
||||
self.nodes.push((node, Some(role)));
|
||||
true
|
||||
} else {
|
||||
false
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
|
|||
378
src/util/bipartite.rs
Normal file
378
src/util/bipartite.rs
Normal file
|
|
@ -0,0 +1,378 @@
|
|||
/*
|
||||
* This module deals with graph algorithm in complete bipartite
|
||||
* graphs. It is used in layout.rs to build the partition to node
|
||||
* assignation.
|
||||
* */
|
||||
|
||||
use std::cmp::{min,max};
|
||||
use std::collections::VecDeque;
|
||||
use rand::prelude::SliceRandom;
|
||||
|
||||
//Graph data structure for the flow algorithm.
|
||||
#[derive(Clone,Copy,Debug)]
|
||||
struct EdgeFlow{
|
||||
c : i32,
|
||||
flow : i32,
|
||||
v : usize,
|
||||
rev : usize,
|
||||
}
|
||||
|
||||
//Graph data structure for the detection of positive cycles.
|
||||
#[derive(Clone,Copy,Debug)]
|
||||
struct WeightedEdge{
|
||||
w : i32,
|
||||
u : usize,
|
||||
v : usize,
|
||||
}
|
||||
|
||||
|
||||
/* This function takes two matchings (old_match and new_match) in a
|
||||
* complete bipartite graph. It returns a matching that has the
|
||||
* same degree as new_match at every vertex, and that is as close
|
||||
* as possible to old_match.
|
||||
* */
|
||||
pub fn optimize_matching( old_match : &Vec<Vec<usize>> ,
|
||||
new_match : &Vec<Vec<usize>> ,
|
||||
nb_right : usize )
|
||||
-> Vec<Vec<usize>> {
|
||||
let nb_left = old_match.len();
|
||||
let ed = WeightedEdge{w:-1,u:0,v:0};
|
||||
let mut edge_vec = vec![ed ; nb_left*nb_right];
|
||||
|
||||
//We build the complete bipartite graph structure, represented
|
||||
//by the list of all edges.
|
||||
for i in 0..nb_left {
|
||||
for j in 0..nb_right{
|
||||
edge_vec[i*nb_right + j].u = i;
|
||||
edge_vec[i*nb_right + j].v = nb_left+j;
|
||||
}
|
||||
}
|
||||
|
||||
for i in 0..edge_vec.len() {
|
||||
//We add the old matchings
|
||||
if old_match[edge_vec[i].u].contains(&(edge_vec[i].v-nb_left)) {
|
||||
edge_vec[i].w *= -1;
|
||||
}
|
||||
//We add the new matchings
|
||||
if new_match[edge_vec[i].u].contains(&(edge_vec[i].v-nb_left)) {
|
||||
(edge_vec[i].u,edge_vec[i].v) =
|
||||
(edge_vec[i].v,edge_vec[i].u);
|
||||
edge_vec[i].w *= -1;
|
||||
}
|
||||
}
|
||||
//Now edge_vec is a graph where edges are oriented LR if we
|
||||
//can add them to new_match, and RL otherwise. If
|
||||
//adding/removing them makes the matching closer to old_match
|
||||
//they have weight 1; and -1 otherwise.
|
||||
|
||||
//We shuffle the edge list so that there is no bias depending in
|
||||
//partitions/zone label in the triplet dispersion
|
||||
let mut rng = rand::thread_rng();
|
||||
edge_vec.shuffle(&mut rng);
|
||||
|
||||
//Discovering and flipping a cycle with positive weight in this
|
||||
//graph will make the matching closer to old_match.
|
||||
//We use Bellman Ford algorithm to discover positive cycles
|
||||
loop{
|
||||
if let Some(cycle) = positive_cycle(&edge_vec, nb_left, nb_right) {
|
||||
for i in cycle {
|
||||
//We flip the edges of the cycle.
|
||||
(edge_vec[i].u,edge_vec[i].v) =
|
||||
(edge_vec[i].v,edge_vec[i].u);
|
||||
edge_vec[i].w *= -1;
|
||||
}
|
||||
}
|
||||
else {
|
||||
//If there is no cycle, we return the optimal matching.
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
//The optimal matching is build from the graph structure.
|
||||
let mut matching = vec![Vec::<usize>::new() ; nb_left];
|
||||
for e in edge_vec {
|
||||
if e.u > e.v {
|
||||
matching[e.v].push(e.u-nb_left);
|
||||
}
|
||||
}
|
||||
matching
|
||||
}
|
||||
|
||||
//This function finds a positive cycle in a bipartite wieghted graph.
|
||||
fn positive_cycle( edge_vec : &Vec<WeightedEdge>, nb_left : usize,
|
||||
nb_right : usize) -> Option<Vec<usize>> {
|
||||
let nb_side_min = min(nb_left, nb_right);
|
||||
let nb_vertices = nb_left+nb_right;
|
||||
let weight_lowerbound = -((nb_left +nb_right) as i32) -1;
|
||||
let mut accessed = vec![false ; nb_left];
|
||||
|
||||
//We try to find a positive cycle accessible from the left
|
||||
//vertex i.
|
||||
for i in 0..nb_left{
|
||||
if accessed[i] {
|
||||
continue;
|
||||
}
|
||||
let mut weight =vec![weight_lowerbound ; nb_vertices];
|
||||
let mut prev =vec![ edge_vec.len() ; nb_vertices];
|
||||
weight[i] = 0;
|
||||
//We compute largest weighted paths from i.
|
||||
//Since the graph is bipartite, any simple cycle has length
|
||||
//at most 2*nb_side_min. In the general Bellman-Ford
|
||||
//algorithm, the bound here is the number of vertices. Since
|
||||
//the number of partitions can be much larger than the
|
||||
//number of nodes, we optimize that.
|
||||
for _ in 0..(2*nb_side_min) {
|
||||
for j in 0..edge_vec.len() {
|
||||
let e = edge_vec[j];
|
||||
if weight[e.v] < weight[e.u]+e.w {
|
||||
weight[e.v] = weight[e.u]+e.w;
|
||||
prev[e.v] = j;
|
||||
}
|
||||
}
|
||||
}
|
||||
//We update the accessed table
|
||||
for i in 0..nb_left {
|
||||
if weight[i] > weight_lowerbound {
|
||||
accessed[i] = true;
|
||||
}
|
||||
}
|
||||
//We detect positive cycle
|
||||
for e in edge_vec {
|
||||
if weight[e.v] < weight[e.u]+e.w {
|
||||
//it means e is on a path branching from a positive cycle
|
||||
let mut was_seen = vec![false ; nb_vertices];
|
||||
let mut curr = e.u;
|
||||
//We track back with prev until we reach the cycle.
|
||||
while !was_seen[curr]{
|
||||
was_seen[curr] = true;
|
||||
curr = edge_vec[prev[curr]].u;
|
||||
}
|
||||
//Now curr is on the cycle. We collect the edges ids.
|
||||
let mut cycle = Vec::<usize>::new();
|
||||
cycle.push(prev[curr]);
|
||||
let mut cycle_vert = edge_vec[prev[curr]].u;
|
||||
while cycle_vert != curr {
|
||||
cycle.push(prev[cycle_vert]);
|
||||
cycle_vert = edge_vec[prev[cycle_vert]].u;
|
||||
}
|
||||
|
||||
return Some(cycle);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
None
|
||||
}
|
||||
|
||||
|
||||
// This function takes two arrays of capacity and computes the
|
||||
// maximal matching in the complete bipartite graph such that the
|
||||
// left vertex i is matched to left_cap_vec[i] right vertices, and
|
||||
// the right vertex j is matched to right_cap_vec[j] left vertices.
|
||||
// To do so, we use Dinic's maximum flow algorithm.
|
||||
pub fn dinic_compute_matching( left_cap_vec : Vec<u32>,
|
||||
right_cap_vec : Vec<u32>) -> Vec< Vec<usize> >
|
||||
{
|
||||
let mut graph = Vec::<Vec::<EdgeFlow> >::new();
|
||||
let ed = EdgeFlow{c:0,flow:0,v:0, rev:0};
|
||||
|
||||
// 0 will be the source
|
||||
graph.push(vec![ed ; left_cap_vec.len()]);
|
||||
for i in 0..left_cap_vec.len()
|
||||
{
|
||||
graph[0][i].c = left_cap_vec[i] as i32;
|
||||
graph[0][i].v = i+2;
|
||||
graph[0][i].rev = 0;
|
||||
}
|
||||
|
||||
//1 will be the sink
|
||||
graph.push(vec![ed ; right_cap_vec.len()]);
|
||||
for i in 0..right_cap_vec.len()
|
||||
{
|
||||
graph[1][i].c = right_cap_vec[i] as i32;
|
||||
graph[1][i].v = i+2+left_cap_vec.len();
|
||||
graph[1][i].rev = 0;
|
||||
}
|
||||
|
||||
//we add left vertices
|
||||
for i in 0..left_cap_vec.len() {
|
||||
graph.push(vec![ed ; 1+right_cap_vec.len()]);
|
||||
graph[i+2][0].c = 0; //directed
|
||||
graph[i+2][0].v = 0;
|
||||
graph[i+2][0].rev = i;
|
||||
|
||||
for j in 0..right_cap_vec.len() {
|
||||
graph[i+2][j+1].c = 1;
|
||||
graph[i+2][j+1].v = 2+left_cap_vec.len()+j;
|
||||
graph[i+2][j+1].rev = i+1;
|
||||
}
|
||||
}
|
||||
|
||||
//we add right vertices
|
||||
for i in 0..right_cap_vec.len() {
|
||||
let lft_ln = left_cap_vec.len();
|
||||
graph.push(vec![ed ; 1+lft_ln]);
|
||||
graph[i+lft_ln+2][0].c = graph[1][i].c;
|
||||
graph[i+lft_ln+2][0].v = 1;
|
||||
graph[i+lft_ln+2][0].rev = i;
|
||||
|
||||
for j in 0..left_cap_vec.len() {
|
||||
graph[i+2+lft_ln][j+1].c = 0; //directed
|
||||
graph[i+2+lft_ln][j+1].v = j+2;
|
||||
graph[i+2+lft_ln][j+1].rev = i+1;
|
||||
}
|
||||
}
|
||||
|
||||
//To ensure the dispersion of the triplets generated by the
|
||||
//assignation, we shuffle the neighbours of the nodes. Hence,
|
||||
//left vertices do not consider the right ones in the same order.
|
||||
let mut rng = rand::thread_rng();
|
||||
for i in 0..graph.len() {
|
||||
graph[i].shuffle(&mut rng);
|
||||
//We need to update the ids of the reverse edges.
|
||||
for j in 0..graph[i].len() {
|
||||
let target_v = graph[i][j].v;
|
||||
let target_rev = graph[i][j].rev;
|
||||
graph[target_v][target_rev].rev = j;
|
||||
}
|
||||
}
|
||||
|
||||
let nb_vertices = graph.len();
|
||||
|
||||
//We run Dinic's max flow algorithm
|
||||
loop{
|
||||
//We build the level array from Dinic's algorithm.
|
||||
let mut level = vec![-1; nb_vertices];
|
||||
|
||||
let mut fifo = VecDeque::new();
|
||||
fifo.push_back((0,0));
|
||||
while !fifo.is_empty() {
|
||||
if let Some((id,lvl)) = fifo.pop_front(){
|
||||
if level[id] == -1 {
|
||||
level[id] = lvl;
|
||||
for e in graph[id].iter(){
|
||||
if e.c-e.flow > 0{
|
||||
fifo.push_back((e.v,lvl+1));
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
if level[1] == -1 {
|
||||
//There is no residual flow
|
||||
break;
|
||||
}
|
||||
|
||||
//Now we run DFS respecting the level array
|
||||
let mut next_nbd = vec![0; nb_vertices];
|
||||
let mut lifo = VecDeque::new();
|
||||
|
||||
let flow_upper_bound;
|
||||
if let Some(x) = left_cap_vec.iter().max() {
|
||||
flow_upper_bound=*x as i32;
|
||||
}
|
||||
else {
|
||||
flow_upper_bound = 0;
|
||||
assert!(false);
|
||||
}
|
||||
|
||||
lifo.push_back((0,flow_upper_bound));
|
||||
|
||||
loop
|
||||
{
|
||||
if let Some((id_tmp, f_tmp)) = lifo.back() {
|
||||
let id = *id_tmp;
|
||||
let f = *f_tmp;
|
||||
if id == 1 {
|
||||
//The DFS reached the sink, we can add a
|
||||
//residual flow.
|
||||
lifo.pop_back();
|
||||
while !lifo.is_empty() {
|
||||
if let Some((id,_)) = lifo.pop_back(){
|
||||
let nbd=next_nbd[id];
|
||||
graph[id][nbd].flow += f;
|
||||
let id_v = graph[id][nbd].v;
|
||||
let nbd_v = graph[id][nbd].rev;
|
||||
graph[id_v][nbd_v].flow -= f;
|
||||
}
|
||||
}
|
||||
lifo.push_back((0,flow_upper_bound));
|
||||
continue;
|
||||
}
|
||||
//else we did not reach the sink
|
||||
let nbd = next_nbd[id];
|
||||
if nbd >= graph[id].len() {
|
||||
//There is nothing to explore from id anymore
|
||||
lifo.pop_back();
|
||||
if let Some((parent, _)) = lifo.back(){
|
||||
next_nbd[*parent] +=1;
|
||||
}
|
||||
continue;
|
||||
}
|
||||
//else we can try to send flow from id to its nbd
|
||||
let new_flow = min(f,graph[id][nbd].c
|
||||
- graph[id][nbd].flow);
|
||||
if level[graph[id][nbd].v] <= level[id] ||
|
||||
new_flow == 0 {
|
||||
//We cannot send flow to nbd.
|
||||
next_nbd[id] += 1;
|
||||
continue;
|
||||
}
|
||||
//otherwise, we send flow to nbd.
|
||||
lifo.push_back((graph[id][nbd].v, new_flow));
|
||||
}
|
||||
else {
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//We return the association
|
||||
let assoc_table = (0..left_cap_vec.len()).map(
|
||||
|id| graph[id+2].iter()
|
||||
.filter(|e| e.flow > 0)
|
||||
.map( |e| e.v-2-left_cap_vec.len())
|
||||
.collect()).collect();
|
||||
|
||||
//consistency check
|
||||
|
||||
//it is a flow
|
||||
for i in 3..graph.len(){
|
||||
assert!( graph[i].iter().map(|e| e.flow).sum::<i32>() == 0);
|
||||
for e in graph[i].iter(){
|
||||
assert!(e.flow + graph[e.v][e.rev].flow == 0);
|
||||
}
|
||||
}
|
||||
|
||||
//it solves the matching problem
|
||||
for i in 0..left_cap_vec.len(){
|
||||
assert!(left_cap_vec[i] as i32 ==
|
||||
graph[i+2].iter().map(|e| max(0,e.flow)).sum::<i32>());
|
||||
}
|
||||
for i in 0..right_cap_vec.len(){
|
||||
assert!(right_cap_vec[i] as i32 ==
|
||||
graph[i+2+left_cap_vec.len()].iter()
|
||||
.map(|e| max(0,e.flow)).sum::<i32>());
|
||||
}
|
||||
|
||||
|
||||
assoc_table
|
||||
}
|
||||
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
|
||||
#[test]
|
||||
fn test_flow() {
|
||||
let left_vec = vec![3;8];
|
||||
let right_vec = vec![0,4,8,4,8];
|
||||
//There are asserts in the function that computes the flow
|
||||
let _ = dinic_compute_matching(left_vec, right_vec);
|
||||
}
|
||||
|
||||
//maybe add tests relative to the matching optilization ?
|
||||
}
|
||||
|
||||
|
||||
|
|
@ -4,6 +4,7 @@
|
|||
extern crate tracing;
|
||||
|
||||
pub mod background;
|
||||
pub mod bipartite;
|
||||
pub mod config;
|
||||
pub mod crdt;
|
||||
pub mod data;
|
||||
|
|
|
|||
Loading…
Reference in a new issue