From 5243882ed56b0b9cb75909ab65291f0ff72376f1 Mon Sep 17 00:00:00 2001
From: Faerbit <faerbit@gmail.com>
Date: Sat, 13 Jun 2020 21:30:03 +0200
Subject: [PATCH] Make random generator thread_local.

---
 util.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/util.h b/util.h
index c26f25d..ae9d1a0 100644
--- a/util.h
+++ b/util.h
@@ -4,6 +4,7 @@
 #include <limits>
 #include <random>
 #include <ctime>
+#include <functional>
 
 const double infinity = std::numeric_limits<double>::infinity();
 const double pi = 3.1415926535897932385;
@@ -15,8 +16,9 @@ inline double degrees_to_radians(double degrees) {
 inline double random_double() {
     static std::uniform_real_distribution<double> distribution(0.0, 1.0);
     //static std::mt19937 generator(std::time(nullptr));
-    static std::mt19937 generator(std::random_device{}());
-    return distribution(generator);
+    static thread_local std::mt19937 generator(std::random_device{}());
+    static std::function<double()> rand_gen = std::bind(distribution, generator);
+    return rand_gen();
 }
 
 inline double random_double(double min, double max) {