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Move dijkstra to new file

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This commit is contained in:
Joscha 2024-12-31 11:26:32 +01:00
parent 6ca20c9740
commit 0168373509
2 changed files with 79 additions and 76 deletions
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78
brood/src/algo.rs
View file

@ -1,77 +1,3 @@
use std::{cmp::Reverse, collections::BinaryHeap}; mod dijkstra;
use crate::graph::{EdgeIdx, Graph, NodeIdx}; pub use self::dijkstra::*;
pub struct Dijkstra<'a> {
graph: &'a Graph,
cost: Vec<u32>,
pred: Vec<NodeIdx>,
}
impl<'a> Dijkstra<'a> {
pub fn new(graph: &'a Graph) -> Self {
Self {
graph,
cost: vec![u32::MAX; graph.nodes.len()],
pred: vec![NodeIdx::NONE; graph.nodes.len()],
}
}
pub fn run(
&mut self,
start: NodeIdx,
goal: impl Fn(NodeIdx) -> bool,
cost: impl Fn(NodeIdx, EdgeIdx, NodeIdx) -> u32,
) {
self.cost[start.usize()] = 0;
let mut queue = BinaryHeap::new();
queue.push((Reverse(0), start));
while let Some((Reverse(curr_cost), curr)) = queue.pop() {
if goal(curr) {
break; // We've found the shortest path to our target
}
// These seem to never actually occur
// if curr_cost > self.cost[curr.usize()] {
// continue; // Outdated entry
// }
for edge in self.graph.edge_range(curr).map(EdgeIdx::new) {
let next = self.graph.edges[edge.usize()];
let next_cost = curr_cost + cost(curr, edge, next);
if next_cost < self.cost[next.usize()] {
self.cost[next.usize()] = next_cost;
self.pred[next.usize()] = curr;
queue.push((Reverse(next_cost), next));
}
}
}
}
#[inline]
pub fn cost(&self, node: NodeIdx) -> u32 {
self.cost[node.usize()]
}
#[inline]
pub fn pred(&self, node: NodeIdx) -> NodeIdx {
self.pred[node.usize()]
}
pub fn path(&self, goal: NodeIdx) -> Vec<NodeIdx> {
let mut path = vec![];
let mut at = goal;
loop {
path.push(at);
at = self.pred(at);
if at == NodeIdx::NONE {
break;
}
}
path.reverse();
path
}
}

77
brood/src/algo/dijkstra.rs Normal file
View file

@ -0,0 +1,77 @@
use std::{cmp::Reverse, collections::BinaryHeap};
use crate::graph::{EdgeIdx, Graph, NodeIdx};
pub struct Dijkstra<'a> {
graph: &'a Graph,
cost: Vec<u32>,
pred: Vec<NodeIdx>,
}
impl<'a> Dijkstra<'a> {
pub fn new(graph: &'a Graph) -> Self {
Self {
graph,
cost: vec![u32::MAX; graph.nodes.len()],
pred: vec![NodeIdx::NONE; graph.nodes.len()],
}
}
pub fn run(
&mut self,
start: NodeIdx,
goal: impl Fn(NodeIdx) -> bool,
cost: impl Fn(NodeIdx, EdgeIdx, NodeIdx) -> u32,
) {
self.cost[start.usize()] = 0;
let mut queue = BinaryHeap::new();
queue.push((Reverse(0), start));
while let Some((Reverse(curr_cost), curr)) = queue.pop() {
if goal(curr) {
break; // We've found the shortest path to our target
}
// These seem to never actually occur
// if curr_cost > self.cost[curr.usize()] {
// continue; // Outdated entry
// }
for edge in self.graph.edge_range(curr).map(EdgeIdx::new) {
let next = self.graph.edges[edge.usize()];
let next_cost = curr_cost + cost(curr, edge, next);
if next_cost < self.cost[next.usize()] {
self.cost[next.usize()] = next_cost;
self.pred[next.usize()] = curr;
queue.push((Reverse(next_cost), next));
}
}
}
}
#[inline]
pub fn cost(&self, node: NodeIdx) -> u32 {
self.cost[node.usize()]
}
#[inline]
pub fn pred(&self, node: NodeIdx) -> NodeIdx {
self.pred[node.usize()]
}
pub fn path(&self, goal: NodeIdx) -> Vec<NodeIdx> {
let mut path = vec![];
let mut at = goal;
loop {
path.push(at);
at = self.pred(at);
if at == NodeIdx::NONE {
break;
}
}
path.reverse();
path
}
}