diff --git a/include/HPDDM_schwarz.hpp b/include/HPDDM_schwarz.hpp
index 3681f13..72f3abe 100644
--- a/include/HPDDM_schwarz.hpp
+++ b/include/HPDDM_schwarz.hpp
@@ -236,2 +236,4 @@ class Schwarz : public Preconditioner<
                 n = 0;
+                int rankW;
+                MPI_Comm_rank(MPI_COMM_WORLD, &rankW);
                 for(unsigned short i = 0, size = Subdomain<K>::_map.size(); i < size; ++i) {
@@ -244,2 +246,4 @@ class Schwarz : public Preconditioner<
                     n += Subdomain<K>::_map[i].second.size();
+                    std::cout << "rank " << rankW << " sending/receiving " << Subdomain<K>::_map[i].second.size() << " to " << Subdomain<K>::_map[i].first << std::endl;
+
                 }
@@ -253,4 +257,7 @@ class Schwarz : public Preconditioner<
                 for(unsigned short i = 0, size = Subdomain<K>::_map.size(); i < size; ++i) {
-                    int index;
-                    MPI_Waitany(size, Subdomain<K>::_rq, &index, MPI_STATUS_IGNORE);
+                    int index, count;
+                    MPI_Status st;
+                    MPI_Waitany(size, Subdomain<K>::_rq, &index, &st);
+                    MPI_Get_count(&st, Wrapper<K>::mpi_underlying_type(), &count);
+                    std::cout << "rank " << rankW << " received from " << Subdomain<K>::_map[index].first << " (" << st.MPI_SOURCE << ") with tag " << st.MPI_TAG << " and count " << count << std::endl;
                     for(int j = 0; j < Subdomain<K>::_map[index].second.size(); ++j)