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// use petgraph::algo::ford_fulkerson;
// use petgraph::prelude::Graph;
use crate::algo::ford_fulkerson::ford_fulkerson;
use crate::prelude::*;
#[test]
fn test_ford_fulkerson() {
// Example from https://downey.io/blog/max-flow-ford-fulkerson-algorithm-explanation/
// let mut graph = Graph::<usize, u16>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let destination = graph.add_node(3);
// graph.extend_with_edges(&[(0, 1, 3), (0, 2, 2), (1, 2, 5), (1, 3, 2), (2, 3, 3)]);
hypergraph! {
let mut graph: DirectedHypergraph<usize, u16> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let destination = 3;
};
edges: {
([source] -> [one]) = 3;
([source] -> [two]) = 2;
([one] -> [two]) = 5;
([one] -> [destination]) = 2;
([two] -> [destination]) = 3;
};
}
}
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(5, max_flow);
// Example from https://brilliant.org/wiki/ford-fulkerson-algorithm/
// let mut graph = Graph::<usize, f32>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let _ = graph.add_node(3);
// let _ = graph.add_node(4);
// let destination = graph.add_node(5);
// graph.extend_with_edges(&[
// (0, 1, 4.),
// (0, 2, 3.),
// (1, 3, 4.),
// (2, 4, 6.),
// (3, 2, 3.),
// (3, 5, 2.),
// (4, 5, 6.),
// ]);
hypergraph! {
let mut graph: DirectedHypergraph<usize, usize> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let three = 3;
let four = 4;
let destination = 5;
};
edges: {
([source] -> [one]) = 4;
([source] -> [two]) = 3;
([one] -> [three]) = 4;
([two] -> [four]) = 6;
([three] -> [two]) = 3;
([three] -> [destination]) = 2;
([four] -> [destination]) = 6;
};
}
}
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(7, max_flow);
// Example from https://cp-algorithms.com/graph/edmonds_karp.html
// let mut graph = Graph::<usize, f32>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let _ = graph.add_node(3);
// let _ = graph.add_node(4);
// let destination = graph.add_node(5);
// graph.extend_with_edges(&[
// (0, 1, 7.),
// (0, 2, 4.),
// (1, 3, 5.),
// (1, 4, 3.),
// (2, 1, 3.),
// (2, 4, 2.),
// (3, 5, 8.),
// (4, 3, 3.),
// (4, 5, 5.),
// ]);
// let (max_flow, _) = ford_fulkerson(&graph, source, destination);
// assert_eq!(10.0, max_flow);
hypergraph! {
let mut graph: DirectedHypergraph<usize, usize> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let three = 3;
let four = 4;
let destination = 5;
};
edges: {
([source] -> [one]) = 7;
([source] -> [two]) = 4;
([one] -> [three]) = 5;
([one] -> [four]) = 3;
([two] -> [one]) = 3;
([two] -> [four]) = 2;
([three] -> [destination]) = 8;
([four] -> [three]) = 3;
([four] -> [destination]) = 5;
};
}
}
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(10, max_flow);
// Example from https://www.programiz.com/dsa/ford-fulkerson-algorithm (corrected: result not 6 but 5)
// let mut graph = Graph::<u8, f32>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let _ = graph.add_node(3);
// let _ = graph.add_node(4);
// let destination = graph.add_node(5);
// graph.extend_with_edges(&[
// (0, 1, 8.),
// (0, 2, 3.),
// (1, 3, 9.),
// (2, 3, 7.),
// (2, 4, 4.),
// (3, 5, 2.),
// (4, 5, 5.),
// ]);
// let (max_flow, _) = ford_fulkerson(&graph, source, destination);
// assert_eq!(5.0, max_flow);
hypergraph! {
let mut graph: DirectedHypergraph<usize, usize> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let three = 3;
let four = 4;
let destination = 5;
};
edges: {
([source] -> [one]) = 8;
([source] -> [two]) = 3;
([one] -> [three]) = 9;
([two] -> [three]) = 7;
([two] -> [four]) = 4;
([three] -> [destination]) = 2;
([four] -> [destination]) = 5;
};
}
}
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(5, max_flow);
// let mut graph = Graph::<u8, u8>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let _ = graph.add_node(3);
// let _ = graph.add_node(4);
// let destination = graph.add_node(5);
// graph.extend_with_edges(&[
// (0, 1, 16),
// (0, 2, 13),
// (1, 2, 10),
// (1, 3, 12),
// (2, 1, 4),
// (2, 4, 14),
// (3, 2, 9),
// (3, 5, 20),
// (4, 3, 7),
// (4, 5, 4),
// ]);
// let (max_flow, _) = ford_fulkerson(&graph, source, destination);
// assert_eq!(23, max_flow);
hypergraph! {
let mut graph: DirectedHypergraph<usize, usize> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let three = 3;
let four = 4;
let destination = 5;
};
edges: {
([source] -> [one]) = 16;
([source] -> [two]) = 13;
([one] -> [two]) = 10;
([one] -> [three]) = 12;
([two] -> [one]) = 4;
([two] -> [four]) = 14;
([three] -> [two]) = 9;
([three] -> [destination]) = 20;
([four] -> [three]) = 7;
([four] -> [destination]) = 4;
};
}
};
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(23, max_flow);
// Example taken from https://medium.com/@jithmisha/solving-the-maximum-flow-problem-with-ford-fulkerson-method-3fccc2883dc7
// let mut graph = Graph::<u8, u8>::new();
// let source = graph.add_node(0);
// let _ = graph.add_node(1);
// let _ = graph.add_node(2);
// let _ = graph.add_node(3);
// let _ = graph.add_node(4);
// let destination = graph.add_node(5);
// graph.extend_with_edges(&[
// (0, 1, 10),
// (0, 2, 10),
// (1, 2, 2),
// (1, 3, 4),
// (1, 4, 8),
// (2, 4, 9),
// (3, 5, 10),
// (4, 3, 6),
// (4, 5, 10),
// ]);
// let (max_flow, _) = ford_fulkerson(&graph, source, destination);
// assert_eq!(19, max_flow);
hypergraph! {
let mut graph: DirectedHypergraph<usize, usize> {
nodes: {
let source = 0;
let one = 1;
let two = 2;
let three = 3;
let four = 4;
let destination = 5;
};
edges: {
([source] -> [one]) = 10;
([source] -> [two]) = 10;
([one] -> [two]) = 2;
([one] -> [three]) = 4;
([one] -> [four]) = 8;
([two] -> [four]) = 9;
([three] -> [destination]) = 10;
([four] -> [three]) = 6;
([four] -> [destination]) = 10;
};
}
};
let Some((max_flow, _)) = ford_fulkerson(&graph, source, destination, |u| {
*graph.edge_weight(u).unwrap()
}) else {
panic!("Ford-Fulkerson failed to find a max flow.");
};
assert_eq!(19, max_flow);
}