Merge pull request #27 from timbeurskens/performance-improvements

Optimized mk_choice function

.github/workflows/rust.yml

@@ -17,6 +17,6 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - name: Build
-      run: cargo build --verbose --release
+      run: cargo build --verbose --release --examples --bins --lib
     - name: Run tests
       run: cargo test --verbose --release

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rsbdd"
-version = "0.6.4"
+version = "0.6.5"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

src/bdd.rs

@@ -182,13 +182,15 @@ impl<S: BDDSymbol> BDDEnv<S> {
         // early simplification step
         let ins = self.simplify(&Rc::new(BDD::Choice(true_subtree, symbol, false_subtree)));
 
-        if self.nodes.borrow().contains_key(&ins) {
-            self.find(&ins)
+        // pre-borrow the nodes as mutable
+        let mut nodes_borrow = self.nodes.borrow_mut();
+
+        // if the node already exists, return a reference to it
+        if let Some(subtree) = nodes_borrow.get(&ins) {
+            Rc::clone(subtree)
         } else {
             // only insert if it is not already in the lookup table
-            self.nodes
-                .borrow_mut()
-                .insert(ins.as_ref().clone(), Rc::clone(&ins));
+            nodes_borrow.insert(ins.as_ref().clone(), Rc::clone(&ins));
             Rc::clone(&ins)
         }
     }