diff --git a/eo/src/mpi/eoMpiAssignmentAlgorithm.cpp b/eo/src/mpi/eoMpiAssignmentAlgorithm.cpp
index 3e7ff025..39ce02f1 100644
--- a/eo/src/mpi/eoMpiAssignmentAlgorithm.cpp
+++ b/eo/src/mpi/eoMpiAssignmentAlgorithm.cpp
@@ -99,7 +99,7 @@ namespace eo
          * STATIC ASSIGNMENT ALGORITHM **************************
          *******************************************************/
 
-        StaticAssignmentAlgorithm::StaticAssignmentAlgorithm( std::vector<int>& workers, int runs )
+        StaticAssignmentAlgorithm::StaticAssignmentAlgorithm( const std::vector<int>& workers, int runs )
         {
             init( workers, runs );
         }
@@ -138,7 +138,7 @@ namespace eo
             init( workers, runs );
         }
 
-        void StaticAssignmentAlgorithm::init( std::vector<int> & workers, int runs )
+        void StaticAssignmentAlgorithm::init( const std::vector<int> & workers, int runs )
         {
             unsigned int nbWorkers = workers.size();
             freeWorkers = nbWorkers;
diff --git a/eo/src/mpi/eoMpiAssignmentAlgorithm.h b/eo/src/mpi/eoMpiAssignmentAlgorithm.h
index 3389db68..abe465b8 100644
--- a/eo/src/mpi/eoMpiAssignmentAlgorithm.h
+++ b/eo/src/mpi/eoMpiAssignmentAlgorithm.h
@@ -177,7 +177,7 @@ namespace eo
                  * @param workers std::vector of MPI ranks of workers which will be used.
                  * @param runs Fixed amount of runs, strictly positive.
                  */
-                StaticAssignmentAlgorithm( std::vector<int>& workers, int runs );
+                StaticAssignmentAlgorithm( const std::vector<int>& workers, int runs );
 
                 /**
                  * @brief Uses a range of workers.
@@ -215,7 +215,7 @@ namespace eo
                  * @param workers Vector of hosts' ranks
                  * @param runs Fixed amount of runs, strictly positive.
                  */
-                void init( std::vector<int> & workers, int runs );
+                void init( const std::vector<int> & workers, int runs );
 
             public:
                 int get( );