diff --git a/lib/linalg/Vector.cpp b/lib/linalg/Vector.cpp
index f2cf07966..9771ecaef 100644
--- a/lib/linalg/Vector.cpp
+++ b/lib/linalg/Vector.cpp
@@ -585,10 +585,11 @@ double Vector::localMin(int nmax)
 }
 
 void
-Vector::distribute(const int &local_dim)
+Vector::distribute(const int local_dim)
 {
     CAROM_VERIFY(!distributed());
     CAROM_VERIFY(d_owns_data);
+    CAROM_VERIFY(local_dim > 0);
 
     std::vector<int> row_offsets;
     int global_dim = get_global_offsets(local_dim, row_offsets,
diff --git a/lib/linalg/Vector.h b/lib/linalg/Vector.h
index 780229457..40405fb1b 100644
--- a/lib/linalg/Vector.h
+++ b/lib/linalg/Vector.h
@@ -768,12 +768,14 @@ class Vector
      * @pre d_owns_data
      *
      * @param[in] local_dim dimension for local MPI rank.
+     *                      Its sum over all processes should be the same as the current dimension.
      */
-    void distribute(const int &local_dim);
+    void distribute(const int local_dim);
 
     /**
      * @brief Gather all the distributed elements among MPI processes.
      * This becomes not distributed after this function is executed.
+     * The data is identical on all processes after the operation.
      *
      * @pre distributed()
      * @pre d_owns_data