Change time to use i64 instead of u64

src/agent.rs

@@ -4,11 +4,11 @@ use crate::{gaussian::Gaussian, player::Player, N_INF};
 pub(crate) struct Agent {
     pub(crate) player: Player,
     pub(crate) message: Gaussian,
-    pub(crate) last_time: u64,
+    pub(crate) last_time: i64,
 }
 
 impl Agent {
-    pub(crate) fn receive(&self, elapsed: u64) -> Gaussian {
+    pub(crate) fn receive(&self, elapsed: i64) -> Gaussian {
         if self.message != N_INF {
             self.message.forget(self.player.gamma, elapsed)
         } else {
@@ -22,7 +22,7 @@ impl Default for Agent {
         Self {
             player: Player::default(),
             message: N_INF,
-            last_time: u64::MIN,
+            last_time: i64::MIN,
         }
     }
 }
@@ -32,7 +32,7 @@ pub(crate) fn clean<'a, A: Iterator<Item = &'a mut Agent>>(agents: A, last_time:
         a.message = N_INF;
 
         if last_time {
-            a.last_time = 0;
+            a.last_time = i64::MIN;
         }
     }
 }