diff --git a/TurTLE/test/test_turtle_NSVE_Stokes_particles.py b/TurTLE/test/test_turtle_NSVE_Stokes_particles.py
index 9428b3f8dbfe74647a1b7399ec70e6e5ff94bf41..d1372600fd63ffd0b96c59363e13ff85b908e288 100644
--- a/TurTLE/test/test_turtle_NSVE_Stokes_particles.py
+++ b/TurTLE/test/test_turtle_NSVE_Stokes_particles.py
@@ -63,8 +63,8 @@ def main():
              sys.argv[1:])
     f = h5py.File('quiescent_nsve_stokes_particles_particles.h5', 'r')
     print(f['tracers0/momentum/0'][:])
-    print(f['tracers0/momentum/0'][:]-f['tracers0/momentum/100'][:])
-    print(f['tracers0/position/0'][:]-f['tracers0/position/100'][:])
+    print(f['tracers0/momentum/100'][:]-f['tracers0/momentum/0'][:])
+    print(f['tracers0/position/100'][:]-f['tracers0/position/0'][:])
     return None
 
 if __name__ == '__main__':
diff --git a/cpp/full_code/NSVE_Stokes_particles.cpp b/cpp/full_code/NSVE_Stokes_particles.cpp
index 4c90dbc226e2bbc7a92ff43de75d6eea1f5ca36b..ef1c13ce5aaf78dc11285a790d0b29b34d892aca 100644
--- a/cpp/full_code/NSVE_Stokes_particles.cpp
+++ b/cpp/full_code/NSVE_Stokes_particles.cpp
@@ -46,7 +46,7 @@ int NSVE_Stokes_particles<rnumber>::initialize(void)
 
     particles_inner_computer_2nd_order_Stokes<double, long long int> current_particles_inner_computer;
     current_particles_inner_computer.set_drag_coefficient(0.1);
-
+    DEBUG_MSG("drag coefficient is set to %f \n", current_particles_inner_computer.get_drag_coefficient());
     //DEBUG_MSG_WAIT(MPI_COMM_WORLD, "before call to particles_system_builder\n");
     this->ps = particles_system_builder_with_p2p(
                 this->fs->cvelocity,                                                    // (field object)
@@ -61,7 +61,7 @@ int NSVE_Stokes_particles<rnumber>::initialize(void)
                 this->comm,
                 this->fs->iteration+1,
                 std::move(p2p_ghost_collisions<double, long long int>()),
-                std::move(particles_inner_computer_2nd_order_Stokes<double, long long int>()),
+                std::move(current_particles_inner_computer),
                 this->tracers0_cutoff);
     //DEBUG_MSG_WAIT(MPI_COMM_WORLD, "after call to particles_system_builder\n");
     this->particles_output_writer_mpi = new particles_output_hdf5<
@@ -79,6 +79,7 @@ int NSVE_Stokes_particles<rnumber>::initialize(void)
                 "tracers0",
                 "position/0");
     this->particles_sample_writer_mpi->setParticleFileLayout(this->ps->getParticleFileLayout());
+    DEBUG_MSG("drag coefficient is after initialization %f \n", current_particles_inner_computer.get_drag_coefficient());
     return EXIT_SUCCESS;
 }
 
diff --git a/cpp/particles/particles_system.hpp b/cpp/particles/particles_system.hpp
index f276abfd6cbba028352027b43ebd98d0dfacc161..ec77ccedf8296bd3dc352515f95fcdad9c29d1be 100644
--- a/cpp/particles/particles_system.hpp
+++ b/cpp/particles/particles_system.hpp
@@ -266,7 +266,7 @@ public:
     void move(const real_number dt) final {
         TIMEZONE("particles_system::move");
         positions_updater.move_particles(my_particles_positions.get(), my_nb_particles,
-                                my_particles_rhs.data(), std::min(step_idx,int(my_particles_rhs.size())),
+                                         my_particles_rhs.data(), std::min(step_idx, int(my_particles_rhs.size())),
                                 dt);
     }