diff --git a/build_vcluster.sh b/build_vcluster.sh
index 4cd2ea71cd468e338e952b5ab2c9c567e1cae3ab..c124c9c93037d441e0d4b644871de87e18d98d99 100644
--- a/build_vcluster.sh
+++ b/build_vcluster.sh
@@ -85,8 +85,9 @@ ulimit -s unlimited\n
  echo $script | sed -r 's/\\n/\n/g' > run_script
  chmod a+x run_script
 
- srun --nodes=1 --ntasks-per-node=16 --time=04:00:00 --mem-per-cpu=1900 --partition=sandy run_script
- if [ $? -ne 0 ]; then exit 1 ; fi
+ salloc --nodes=1 --ntasks-per-node=16 --time=04:00:00 --mem-per-cpu=1900 --partition=sandy mpirun -np 16 src/vcluster
+# srun --nodes=1 --ntasks-per-node=16 --time=04:00:00 --mem-per-cpu=1900 --partition=sandy run_script
+# if [ $? -ne 0 ]; then exit 1 ; fi
 # srun --nodes=2 --ntasks-per-node=16 --time=04:00:00 --mem-per-cpu=1900 --partition=sandy run_script
 # if [ $? -ne 0 ]; then exit 1 ; fi
 # srun --nodes=4 --ntasks-per-node=16 --time=04:00:00 --mem-per-cpu=1900 --partition=sandy run_script
diff --git a/src/VCluster_unit_tests.hpp b/src/VCluster_unit_tests.hpp
index 5396bf995b86338d5907c9da005e932e2d7817bb..c82afcaa53984f7271af49c01cc4be7f5d4f7359 100644
--- a/src/VCluster_unit_tests.hpp
+++ b/src/VCluster_unit_tests.hpp
@@ -413,7 +413,7 @@ BOOST_AUTO_TEST_CASE( VCluster_use_sendrecv)
 			// Check the message
 			for (size_t i = 0 ; i < 8  && i < n_proc ; i++)
 			{
-				long int p_id = vcl.getProcessUnitID() - i - 1;
+				long int p_id = ((i+1) * ps + vcl.getProcessUnitID()) % n_proc;
 				if (p_id < 0)
 					p_id += n_proc;
 				else