fix building of examples
diff --git a/doc/snippets/compile_snippet.cpp.in b/doc/snippets/compile_snippet.cpp.in
index 1164b9d..5d8e53a 100644
--- a/doc/snippets/compile_snippet.cpp.in
+++ b/doc/snippets/compile_snippet.cpp.in
@@ -1,4 +1,5 @@
 #include <Eigen/Core>
+#include <Eigen/Array>
 #include <Eigen/LU>
 USING_PART_OF_NAMESPACE_EIGEN
 using namespace std;