Add parallel Nash and Pareto methods

t4t-games/src/rps.rs

@@ -94,7 +94,7 @@ pub fn fire_water() -> Normal<Move, i64, 2> {
 ///
 /// Note that `rps1000` demonstrates that `Normal` can represent extremely large games---this game
 /// has a payoff table with `3^1000` entries! Such large games can be represented and played
-/// without issue, but any function that iterates over the outcomes (such as
+/// without issue. However, any function that iterates over the outcomes (such as
 /// [`is_zero_sum`](t4t::Normal::is_zero_sum) or any solution concept), will leave you waiting
 /// beyond the heat death of the universe.
 #[rustfmt::skip]

t4t/Cargo.toml

@@ -17,6 +17,7 @@ log = "0.4.21"
 num = "0.4.3"
 rand = "0.8.5"
 rand_distr = "0.4.3"
+rayon = "1.10.0"
 
 [dev-dependencies]
 env_logger = "0.11.3"

t4t/src/normal.rs

@@ -1,4 +1,5 @@
 use num::Zero;
+use rayon::prelude::*;
 use std::cmp::Ordering;
 use std::collections::HashMap;
 use std::iter::Iterator;
@@ -587,6 +588,19 @@ impl<M: Move, U: Utility, const P: usize> Normal<M, U, P> {
         nash
     }
 
+    /// A variant of [`pure_nash_equilibria`] that analyzes the outcomes in parallel.
+    pub fn pure_nash_equlibria_parallel(&self) -> Vec<Profile<M, P>> {
+        let (sender, receiver) = std::sync::mpsc::channel();
+        self.possible_profiles()
+            .par_bridge()
+            .for_each_with(sender, |s, profile| {
+                if self.is_stable(profile) {
+                    s.send(profile).unwrap();
+                }
+            });
+        receiver.iter().collect()
+    }
+
     /// Return a new profile that represents a
     /// [Pareto improvement](https://en.wikipedia.org/wiki/Pareto_efficiency)
     /// on the given profile, if one exists.
@@ -634,6 +648,19 @@ impl<M: Move, U: Utility, const P: usize> Normal<M, U, P> {
         pareto
     }
 
+    /// A variant of [`pareto_optimal_solutions`] that analyzes the outcomes in parallel.
+    pub fn pareto_optimal_solutions_parallel(&self) -> Vec<Profile<M, P>> {
+        let (sender, receiver) = std::sync::mpsc::channel();
+        self.possible_profiles()
+            .par_bridge()
+            .for_each_with(sender, |s, profile| {
+                if self.is_pareto_optimal(profile) {
+                    s.send(profile).unwrap();
+                }
+            });
+        receiver.iter().collect()
+    }
+
     /// Get all dominated move relationships for the given player. If a move is dominated by
     /// multiple different moves, it will contain multiple entries in the returned vector.
     ///