Remove unnecessary allocations

src/history.rs

@@ -1,4 +1,4 @@
-use std::collections::{HashMap, HashSet};
+use std::collections::HashMap;
 
 use crate::{
     agent::{self, Agent},
@@ -267,17 +267,27 @@ impl History {
             "(length(weights) > 0) & (length(composition) != length(weights))"
         );
 
+        let mut unique = Vec::with_capacity(10);
+
         let this_agent = composition
             .iter()
             .flatten()
             .flatten()
-            .cloned()
-            .collect::<HashSet<_>>();
+            .filter(|idx| {
+                if !unique.contains(idx) {
+                    unique.push(*idx);
+
+                    return true;
+                }
+
+                false
+            })
+            .collect::<Vec<_>>();
 
         for agent in &this_agent {
             if !self.agents.contains_key(agent) {
                 self.agents.insert(
-                    *agent,
+                    **agent,
                     Agent {
                         player: priors.get(agent).cloned().unwrap_or_else(|| {
                             Player::new(
@@ -473,8 +483,8 @@ mod tests {
 
         let p = Game::new(
             h.batches[1].events[0].within_priors(false, false, &h.batches[1].skills, &h.agents),
-            vec![0.0, 1.0],
-            vec![],
+            &vec![0.0, 1.0],
+            &vec![vec![1.0], vec![1.0]],
             P_DRAW,
         )
         .posteriors();