diff --git a/source/simple/support/random/distribution/diagonal.hpp b/source/simple/support/random/distribution/diagonal.hpp
index 554ec33853a224419cefcea81a1b33c4b5a7b9aa..a939e8fd2d573e005a048c58b83ba9a24def5673 100644
--- a/source/simple/support/random/distribution/diagonal.hpp
+++ b/source/simple/support/random/distribution/diagonal.hpp
@@ -1,6 +1,8 @@
 #ifndef SIMPLE_SUPPORT_RANDOM_DISTRIBUTION_DIAGONAL_HPP
 #define SIMPLE_SUPPORT_RANDOM_DISTRIBUTION_DIAGONAL_HPP
 #include <algorithm>
+#include <ostream>
+#include <istream>
 #include "../../arithmetic.hpp"
 #include "../../algorithm.hpp"
 #include "../../array.hpp"