diff --git a/include/grid_ghosts.hh b/include/grid_ghosts.hh
new file mode 100644
index 0000000..be31ede
--- /dev/null
+++ b/include/grid_ghosts.hh
@@ -0,0 +1,209 @@
+// This file is part of monofonIC (MUSIC2)
+// A software package to generate ICs for cosmological simulations
+// Copyright (C) 2022 by Oliver Hahn
+// 
+// monofonIC is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// monofonIC is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#pragma once
+
+#include <array>
+#include <vector>
+
+#include <numeric>
+
+#include <general.hh>
+#include <math/vec3.hh>
+
+template <int numghosts, bool haveleft, bool haveright, typename grid_t>
+struct grid_with_ghosts
+{
+  using data_t = typename grid_t::data_t;
+  using vec3 = std::array<real_t, 3>;
+
+  static constexpr bool is_distributed_trait = grid_t::is_distributed_trait;
+  static constexpr int num_ghosts = numghosts;
+  static constexpr bool have_left = haveleft, have_right = haveright;
+
+  std::vector<data_t> boundary_left_, boundary_right_;
+  std::vector<int> local0starts_;
+  const grid_t &gridref;
+  size_t nx_, ny_, nz_, nzp_;
+
+
+  //... determine communication offsets
+  std::vector<ptrdiff_t> offsets_, sizes_;
+
+  int get_task(ptrdiff_t index) const
+  {
+    int itask = 0;
+    while (itask < MPI::get_size() - 1 && offsets_[itask + 1] <= index)
+        ++itask;
+    return itask;
+  }
+
+  explicit grid_with_ghosts(const grid_t &g)
+  : gridref(g), nx_(g.n_[0]), ny_(g.n_[1]), nz_(g.n_[2]), nzp_(g.n_[2]+2)
+  {
+    if (is_distributed_trait)
+    {
+      int ntasks(MPI::get_size());
+
+      offsets_.assign(ntasks+1, 0);
+      sizes_.assign(ntasks, 0);
+      
+      MPI_Allgather(&g.local_0_size_, 1, MPI_LONG_LONG, &sizes_[0], 1,
+                      MPI_LONG_LONG, MPI_COMM_WORLD);
+      MPI_Allgather(&g.local_0_start_, 1, MPI_LONG_LONG, &offsets_[0], 1,
+                      MPI_LONG_LONG, MPI_COMM_WORLD);
+      
+      for( int i=0; i< CONFIG::MPI_task_size; i++ ){
+          if( offsets_[i+1] < offsets_[i] + sizes_[i] ) offsets_[i+1] = offsets_[i] + sizes_[i];
+      }
+
+      update_ghosts_allow_multiple( g );
+    }
+  }
+
+  void update_ghosts_allow_multiple( const grid_t &g )
+  {
+  #if defined(USE_MPI)
+    //... exchange boundary
+    if( have_left  ) boundary_left_.assign(num_ghosts * ny_ * nzp_, data_t{0.0});
+    if( have_right ) boundary_right_.assign(num_ghosts * ny_ * nzp_, data_t{0.0});
+
+    size_t slicesz = ny_ * nzp_;
+
+    MPI_Status status;
+    std::vector<MPI_Request> req;
+    MPI_Request temp_req;
+
+    if( have_right ){
+      for( int itask=0; itask<CONFIG::MPI_task_size; ++itask ){
+        for( size_t i=0; i<num_ghosts; ++i ){
+          ptrdiff_t iglobal_request = (offsets_[itask] + sizes_[itask] + i) % g.n_[0];
+          if( iglobal_request >= g.local_0_start_ && iglobal_request < g.local_0_start_ + g.local_0_size_ ){
+            size_t ii = iglobal_request - g.local_0_start_;
+            MPI_Isend( &g.relem(ii*slicesz), slicesz, MPI::get_datatype<data_t>(), itask, iglobal_request, MPI_COMM_WORLD, &temp_req);
+            req.push_back(temp_req);
+          }
+        }
+      }
+
+      //--- receive data ------------------------------------------------------------
+      #pragma omp parallel if(CONFIG::MPI_threads_ok)
+      {
+          MPI_Status status;
+
+          #pragma omp for 
+          for( size_t i=0; i<num_ghosts; ++i ){
+            ptrdiff_t iglobal_request = (g.local_0_start_ + g.local_0_size_ + i) % g.n_[0];
+          
+            int recvfrom = get_task(iglobal_request);
+
+            //#pragma omp critical // need critical region here if we do "MPI_THREAD_FUNNELED", 
+            {
+                // receive data slice and check for MPI errors when in debug mode
+                status.MPI_ERROR = MPI_SUCCESS;
+                MPI_Recv(&boundary_right_[i*slicesz], (int)slicesz, MPI::get_datatype<data_t>(), recvfrom, (int)iglobal_request, MPI_COMM_WORLD, &status);
+                assert(status.MPI_ERROR == MPI_SUCCESS);
+            }
+          }
+      }
+    }
+
+    MPI_Barrier( MPI_COMM_WORLD );
+
+    if( have_left ){
+      for( int itask=0; itask<CONFIG::MPI_task_size; ++itask ){
+        for( size_t i=0; i<num_ghosts; ++i ){
+          ptrdiff_t iglobal_request = (offsets_[itask] + g.n_[0] - num_ghosts + i) % g.n_[0];
+          if( iglobal_request >= g.local_0_start_ && iglobal_request < g.local_0_start_ + g.local_0_size_ ){
+            size_t ii = iglobal_request - g.local_0_start_;
+            MPI_Isend( &g.relem(ii*slicesz), slicesz, MPI::get_datatype<data_t>(), itask, iglobal_request, MPI_COMM_WORLD, &temp_req);
+            req.push_back(temp_req);
+          }
+        }
+      }
+
+      //--- receive data ------------------------------------------------------------
+      #pragma omp parallel if(CONFIG::MPI_threads_ok)
+      {
+          MPI_Status status;
+
+          #pragma omp for 
+          for( size_t i=0; i<num_ghosts; ++i ){
+            ptrdiff_t iglobal_request = (g.local_0_start_ + g.n_[0] - num_ghosts + i) % g.n_[0];
+          
+            int recvfrom = get_task(iglobal_request);
+
+            //#pragma omp critical // need critical region here if we do "MPI_THREAD_FUNNELED", 
+            {
+                // receive data slice and check for MPI errors when in debug mode
+                status.MPI_ERROR = MPI_SUCCESS;
+                MPI_Recv(&boundary_left_[i*slicesz], (int)slicesz, MPI::get_datatype<data_t>(), recvfrom, (int)iglobal_request, MPI_COMM_WORLD, &status);
+                assert(status.MPI_ERROR == MPI_SUCCESS);
+            }
+          }
+      }
+    }
+
+    MPI_Barrier( MPI_COMM_WORLD );
+    
+    for (size_t i = 0; i < req.size(); ++i)
+    {
+        // need to set status as wait does not necessarily modify it
+        // c.f. http://www.open-mpi.org/community/lists/devel/2007/04/1402.php
+        status.MPI_ERROR = MPI_SUCCESS;
+        // std::cout << "task " << CONFIG::MPI_task_rank << " : checking request No" << i << std::endl;
+        int flag(1);
+        MPI_Test(&req[i], &flag, &status);
+        if( !flag ){
+            std::cout << "task " << CONFIG::MPI_task_rank << " : request No" << i << " unsuccessful" << std::endl;
+        }
+
+        MPI_Wait(&req[i], &status);
+        // std::cout << "---> ok!" << std::endl;
+        assert(status.MPI_ERROR == MPI_SUCCESS);
+    }
+
+    MPI_Barrier(MPI_COMM_WORLD);
+    
+    #endif
+  }
+
+  data_t relem(const ptrdiff_t& i, const ptrdiff_t& j, const ptrdiff_t&k ) const noexcept
+  {
+    return this->relem({i,j,k});
+  }
+
+  data_t relem(const std::array<ptrdiff_t, 3> &pos) const noexcept
+  {
+    const ptrdiff_t ix = pos[0];
+    const ptrdiff_t iy = (pos[1]+gridref.n_[1])%gridref.n_[1];
+    const ptrdiff_t iz = (pos[2]+gridref.n_[2])%gridref.n_[2];
+
+    if( is_distributed_trait ){
+      const ptrdiff_t localix = ix;
+      if( localix < 0 ){
+        return boundary_left_[((localix+num_ghosts)*ny_+iy)*nzp_+iz];
+      }else if( localix >= gridref.local_0_size_ ){
+        return boundary_right_[((localix-gridref.local_0_size_)*ny_+iy)*nzp_+iz];
+      }else{
+        return gridref.relem(localix, iy, iz);
+      }
+    }
+
+    return gridref.relem((ix+gridref.n_[0])%gridref.n_[0], iy, iz);
+  }
+};
+