make initial_depth private

src/engine.rs

@@ -243,7 +243,7 @@ impl Engine {
         if si.perft {
             if let Some(dep) = si.depth {
                 depth = dep;
-                sc.initial_depth = depth;
+                sc.set_depth(depth);
             }
             let invalid = perft(&mut self.game, &mut sc, depth as i32);
             if !invalid {

src/search.rs

@@ -23,7 +23,7 @@ pub struct SearchControl<'a> {
     pub move_history: &'a mut RepetitionTable,
 
     /// depth the search was started at
-    pub initial_depth: i32,
+    initial_depth: i32,
 }
 
 pub enum SearchResult {