diff --git a/lib/diagonalizer.hpp b/lib/diagonalizer.hpp
index a8514735fb2367cd107f2a1e60866dc6caf4e055..7d0ab0c04630534f0789e6e635855e409621ef54 100644
--- a/lib/diagonalizer.hpp
+++ b/lib/diagonalizer.hpp
@@ -2,6 +2,7 @@
 #define DIAGONALIZER_HPP_INCLUDED
 #include <vector>
 #include <iostream>
+#include <utility>
 
 extern "C" void dsyev_(
                 char    const & JOBZ,   // 'N': Only eigenvalues, 'V': Eigenvalues and -vectors
@@ -80,7 +81,7 @@ class Diagonalizer{
 
                 int info_;
                 double dwork_;
-                int lwork_; 
+                int lwork_;
                 int N_; //linear matrix dimension
                 std::vector<double> matrix_; //the matrix
                 std::vector<double> eigenvalues_; //eigenvalues
diff --git a/projects/braidingTightBinding/lib/diagonalizer.hpp b/projects/braidingTightBinding/lib/diagonalizer.hpp
index a8514735fb2367cd107f2a1e60866dc6caf4e055..7d0ab0c04630534f0789e6e635855e409621ef54 100644
--- a/projects/braidingTightBinding/lib/diagonalizer.hpp
+++ b/projects/braidingTightBinding/lib/diagonalizer.hpp
@@ -2,6 +2,7 @@
 #define DIAGONALIZER_HPP_INCLUDED
 #include <vector>
 #include <iostream>
+#include <utility>
 
 extern "C" void dsyev_(
                 char    const & JOBZ,   // 'N': Only eigenvalues, 'V': Eigenvalues and -vectors
@@ -80,7 +81,7 @@ class Diagonalizer{
 
                 int info_;
                 double dwork_;
-                int lwork_; 
+                int lwork_;
                 int N_; //linear matrix dimension
                 std::vector<double> matrix_; //the matrix
                 std::vector<double> eigenvalues_; //eigenvalues