Dijkstra Path generic, Closeness Centrality, Iterate Edge with directionality (#20)

Author: dizzyi

examples/centrality.rs

@@ -166,6 +166,52 @@ fn katz_centrality_impl_example() {
     println!("{:.5?}", centrality); // [0.23167, 0.71650, 0.65800]
 }
 
+fn closeness_centrality_example() {
+    use graphina::core::types::Graph;
+
+    use graphina::centrality::algorithms::closeness_centrality;
+
+    let mut graph = Graph::new();
+    let ids = (0..5).map(|i| graph.add_node(i)).collect::<Vec<_>>();
+    let edges = [(0, 1, 1.0), (0, 2, 1.0), (1, 3, 1.0)];
+    for (s, d, w) in edges {
+        graph.add_edge(ids[s], ids[d], w);
+    }
+
+    let centrality = closeness_centrality(&graph, false).unwrap();
+    println!("{:.5?}", centrality); // [0.75000, 0.75000, 0.50000, 0.50000, 0.00000]
+}
+
+fn closeness_centrality_impl_example() {
+    use graphina::core::types::Graph;
+
+    use graphina::centrality::algorithms::closeness_centrality_impl;
+
+    let mut graph: Graph<i32, (String, f64)> = Graph::new();
+
+    let ids = (0..5).map(|i| graph.add_node(i)).collect::<Vec<_>>();
+
+    let edges = [
+        (0, 1, ("friend".to_string(), 0.9)),
+        (0, 2, ("family".to_string(), 0.8)),
+        (1, 3, ("friend".to_string(), 0.7)),
+        (2, 4, ("enemy".to_string(), 0.1)),
+    ];
+    for (s, d, w) in edges {
+        graph.add_edge(ids[s], ids[d], w);
+    }
+
+    let eval_cost = |(s, f): &(String, f64)| match s.as_str() {
+        "friend" => Some(1.0 / *f / 2.0),
+        "family" => Some(1.0 / *f / 4.0),
+        "enemy" => None,
+        _ => Some(1.0 / *f),
+    };
+
+    let centrality = closeness_centrality_impl(&graph, eval_cost, true).unwrap();
+    println!("{:.5?}", centrality); // [1.05244, 1.05244, 0.81436, 0.63088, 0.00000]
+}
+
 macro_rules! run_examples {
     ($($func:ident),* $(,)?) => {
         $(
@@ -189,6 +235,9 @@ fn main() {
         // katz centrality
         katz_centrality_example,
         katz_centrality_numpy_example,
-        katz_centrality_impl_example
+        katz_centrality_impl_example,
+        // closeness centrality
+        closeness_centrality_example,
+        closeness_centrality_impl_example,
     );
 }

examples/path_dijkstra.rs

@@ -0,0 +1,91 @@
+fn line() {
+    use graphina::core::types::Graph;
+
+    use graphina::core::paths::dijkstra_path_f64;
+
+    let mut graph = Graph::new();
+    let ids = (0..5).map(|i| graph.add_node(i)).collect::<Vec<_>>();
+    let edges = [(0, 1, 1.0), (1, 2, 1.0), (2, 3, 2.0), (3, 4, 1.0)];
+    for (s, d, w) in edges {
+        graph.add_edge(ids[s], ids[d], w);
+    }
+
+    let (cost, trace) = dijkstra_path_f64(&graph, ids[0], None).unwrap();
+
+    println!("cost : {:?}", cost);
+    println!("trace: {:?}", trace);
+    // cost : [Some(0.0), Some(1.0), Some(2.0), Some(4.0), Some(5.0)]
+    // trace: [None, Some(NodeId(NodeIndex(0))), Some(NodeId(NodeIndex(1))), Some(NodeId(NodeIndex(2))), Some(NodeId(NodeIndex(3)))]
+}
+
+fn flight() {
+    use graphina::core::types::Digraph;
+
+    use graphina::core::paths::dijkstra_path_impl;
+
+    let mut graph: Digraph<String, (f64, String)> = Digraph::new();
+    //                             ^^^^^^^^^^^^^
+    //                                         L arbitrary type as edge
+
+    let cities = ["ATL", "PEK", "LHR", "HND", "CDG", "FRA", "HKG"];
+
+    let ids = cities
+        .iter()
+        .map(|s| graph.add_node(s.to_string()))
+        .collect::<Vec<_>>();
+
+    let edges = [
+        //
+        ("ATL", "PEK", (900.0, "boeing")),
+        ("ATL", "LHR", (500.0, "airbus")),
+        ("ATL", "HND", (700.0, "airbus")),
+        //
+        ("PEK", "LHR", (800.0, "boeing")),
+        ("PEK", "HND", (100.0, "airbus")),
+        ("PEK", "HKG", (100.0, "airbus")),
+        //
+        ("LHR", "CDG", (100.0, "airbus")),
+        ("LHR", "FRA", (200.0, "boeing")),
+        ("LHR", "HND", (600.0, "airbus")),
+        //
+        ("HND", "ATL", (700.0, "airbus")),
+        ("HND", "FRA", (600.0, "airbus")),
+        ("HND", "HKG", (100.0, "airbus")),
+        //
+    ];
+
+    for (s, d, w) in edges {
+        let depart = cities.iter().position(|city| s == *city).unwrap();
+        let destin = cities.iter().position(|city| d == *city).unwrap();
+        graph.add_edge(ids[depart], ids[destin], (w.0, w.1.to_string()));
+    }
+
+    // function for evaluating possible cost for the edge
+    // Some(f64) for cost
+    // None for impassable
+    let eval_cost = |(price, manufactuer): &(f64, String)| match manufactuer.as_str() {
+        "boeing" => None,  // avoid boeing plane
+        _ => Some(*price), // return price as the cost
+    };
+
+    let (cost, trace) = dijkstra_path_impl(&graph, ids[0], Some(1000.0), eval_cost).unwrap();
+
+    println!("cost : {:?}", cost);
+    println!("trace: {:?}", trace);
+    // cost : [Some(0.0), None, Some(500.0), Some(700.0), Some(600.0), None, Some(800.0)]
+    // trace: [None, None, Some(NodeId(NodeIndex(0))), Some(NodeId(NodeIndex(0))), Some(NodeId(NodeIndex(2))), None, Some(NodeId(NodeIndex(3)))]
+}
+
+macro_rules! run_examples {
+    ($($func:ident),* $(,)?) => {
+        $(
+            println!("<{}>", stringify!($func));
+            $func();
+            println!();
+        )*
+    };
+}
+
+fn main() {
+    run_examples!(line, flight);
+}