Simplify return type of UndirectedGraph::normal_form

Return either vertex orbits or edge orbits, not both.

src/expand_n_contract.rs

@@ -17,7 +17,7 @@ pub fn expand_n_contract(
 
     // NOTE: Start with the normal form of the wheel graph.
     let mut wheel_graph: UndirectedGraph = UndirectedGraph::wheel_graph(num_spokes);
-    let (wheel_graph_sign, wheel_graph_vertex_orbits, _) = wheel_graph.normal_form(false);
+    let (wheel_graph_sign, wheel_graph_vertex_orbits) = wheel_graph.normal_form(false);
     assert!(wheel_graph_sign != 0);
     cocycle_graphs.push(wheel_graph.clone());
     cocycle_graph_index.insert(wheel_graph, 0);
@@ -51,8 +51,7 @@ pub fn expand_n_contract(
             writeln!(sparse_matrix_file, "{} {} {}", dg_idx + 1, g_idx + 1, c)?;
             num_nonzeros += 1;
 
-            let cg_data: HashMap<UndirectedGraph, Vec<usize>> =
-                dg.contractions(&dg_edge_orbits);
+            let cg_data: HashMap<UndirectedGraph, Vec<usize>> = dg.contractions(&dg_edge_orbits);
             for (cg, cg_vertex_orbits) in cg_data {
                 // eprintln!("{:?}", cg);
                 if !cocycle_graph_index.contains_key(&cg) {

src/undirected_graph.rs

@@ -241,7 +241,7 @@ impl UndirectedGraph {
         }
     }
 
-    pub fn normal_form(&mut self, compute_edge_orbits: bool) -> (i32, Vec<usize>, Vec<usize>) {
+    pub fn normal_form(&mut self, compute_edge_orbits: bool) -> (i32, Vec<usize>) {
         let mut options: nauty_Traces_sys::optionblk = nauty_Traces_sys::optionblk {
             getcanon: nauty_Traces_sys::TRUE,
             userautomproc: Some(Self::process_nauty_automorphism),
@@ -292,11 +292,6 @@ impl UndirectedGraph {
             lab_inv[lab[i] as usize] = i as i32;
         }
 
-        let normal_self_orbits: Vec<usize> = orbits
-            .iter()
-            .map(|&v| lab_inv[v as usize] as usize)
-            .collect();
-
         let mut sign: i32 = 1;
         let mut normal_self_edge_orbits: Vec<usize> = vec![];
         Self::EDGE_ORBIT_DATA.with_borrow_mut(|edge_orbit_data: &mut EdgeOrbitData| {
@@ -321,7 +316,15 @@ impl UndirectedGraph {
 
         self.nauty_graph = normal_self.nauty_graph;
 
-        (sign, normal_self_orbits, normal_self_edge_orbits)
+        if compute_edge_orbits {
+            (sign, normal_self_edge_orbits)
+        } else {
+            let normal_self_orbits: Vec<usize> = orbits
+                .iter()
+                .map(|&v| lab_inv[v as usize] as usize)
+                .collect();
+            (sign, normal_self_orbits)
+        }
     }
 
     fn expand_vertex(&self, &position: &usize) -> Vec<(i64, UndirectedGraph)> {
@@ -474,9 +477,7 @@ impl UndirectedGraph {
 
         for (orbit_rep, orbit_size) in orbit_reps {
             for (c, mut dg) in self.expand_vertex(&orbit_rep) {
-                // TODO: Avoid computing orbits when not used.
-                let (normal_dg_sign, _normal_dg_orbits, normal_dg_edge_orbits) =
-                    dg.normal_form(true);
+                let (normal_dg_sign, normal_dg_edge_orbits) = dg.normal_form(true);
                 if normal_dg_sign == 0 {
                     continue;
                 }
@@ -568,7 +569,7 @@ impl UndirectedGraph {
                 nauty_graph: contracted_graph,
             };
 
-            let (normal_cg_sign, normal_cg_orbits, _) = cg.normal_form(false);
+            let (normal_cg_sign, normal_cg_orbits) = cg.normal_form(false);
             if normal_cg_sign == 0 {
                 continue;
             }