diff --git a/src/action.hpp b/src/action.hpp
index 70831e3ffc2993bb54567c73036847a079e811ab..fd35932498f16d895b6bcc0ed7aff36a27a4ee56 100644
--- a/src/action.hpp
+++ b/src/action.hpp
@@ -4,9 +4,8 @@
 #include "common.hpp"
 #include "array.hpp"
 
-
 template <typename Scalar, typename Shape>
-inline Scalar S_2(Array<Scalar, Shape> Q)
+inline Scalar S_2(array::Array<Scalar, Shape> Q)
 {
     size_t nx = Q.dim(0);
     size_t ny = Q.dim(1);
diff --git a/src/array.hpp b/src/array.hpp
index f293caaa8f3aaca2f1a5a1c768cb5a45fcfd2a68..086376fd4a135982fb08559cdc2b67479f620b09 100644
--- a/src/array.hpp
+++ b/src/array.hpp
@@ -7,6 +7,8 @@
 #include <initializer_list>
 #include <stdexcept>
 
+namespace array {
+
 constexpr size_t Dynamic = SIZE_MAX;
 
 /*! Array dimensions and strides: known at compile-time & dynamic
@@ -326,5 +328,6 @@ public:
     operator EigenMap() const { return matrix(); }
 };
 
+} // namespace array
 
 #endif
diff --git a/src/main.cpp b/src/main.cpp
index ee71d97e049e5fd73aea4d963523673307e5430d..dcd6bf49b71b2fed3371a660429f12317a779eb2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3,6 +3,7 @@
 #include "action.hpp"
 
 using namespace std::complex_literals;
+using namespace array;
 
 template <typename Scalar, typename Shape>
 void dump(Array<Scalar,Shape> Q)