diff --git a/src/rnd.cpp b/src/rnd.cpp
index 9cee4098..3d9c44a2 100644
--- a/src/rnd.cpp
+++ b/src/rnd.cpp
@@ -20,6 +20,8 @@
 
 #include "rapidhash/rapidhash.h"
 
+#include <cassert>
+
 #include <sys/time.h>
 
 
@@ -57,6 +59,7 @@ RND::rand64(void)
 u64
 RND::rand64(cu64 max_)
 {
+  assert(max_ > 0);
   return (RND::rand64() % max_);
 }
 
@@ -64,5 +67,6 @@ u64
 RND::rand64(cu64 min_,
             cu64 max_)
 {
+  assert(max_ > min_);
   return (min_ + (RND::rand64() % (max_ - min_)));
 }
diff --git a/src/rnd.hpp b/src/rnd.hpp
index 0cedbfc0..af90fb5c 100644
--- a/src/rnd.hpp
+++ b/src/rnd.hpp
@@ -20,7 +20,7 @@
 
 #include "base_types.h"
 
-#include <random>
+#include <vector>
 
 class RND
 {
@@ -38,14 +38,10 @@ public:
   void
   shrink_to_rand_elem(std::vector<T> &v_)
   {
-    static std::mt19937 gen(std::random_device{}());
-
     if(v_.size() <= 1)
       return;
 
-    std::uniform_int_distribution<> dist(0,(v_.size() - 1));
-
-    std::swap(v_[0],v_[dist(gen)]);
+    std::swap(v_[0],v_[RND::rand64(v_.size())]);
 
     v_.resize(1);
   }