diff --git a/libs/geom/include/psemek/geom/matrix.hpp b/libs/geom/include/psemek/geom/matrix.hpp
index 99ddb673..dd35a9de 100644
--- a/libs/geom/include/psemek/geom/matrix.hpp
+++ b/libs/geom/include/psemek/geom/matrix.hpp
@@ -268,4 +268,16 @@ namespace psemek::geom
 		return result;
 	}
 
+	template <typename Stream, typename T, std::size_t R, std::size_t C>
+	Stream & operator << (Stream & os, matrix<T, R, C> const & m)
+	{
+		for (std::size_t i = 0; i < R; ++i)
+		{
+			for (std::size_t j = 0; j < C; ++j)
+				os << m[i][j] << ' ';
+			os << '\n';
+		}
+		return os;
+	}
+
 }