From eca60276b90ec1ae018c48e201addbf8010ee164 Mon Sep 17 00:00:00 2001
From: benjamin <benjamin.brands@fau.de>
Date: Sat, 27 Jan 2018 22:25:55 +0100
Subject: [PATCH] Move implementation of MPI::all_gather()

---
 include/deal.II/base/mpi.h           | 49 ++++++++++++++++++++++++++
 include/deal.II/base/mpi.templates.h | 51 ----------------------------
 tests/base/mpi_all_gather_01.cc      |  2 +-
 tests/base/mpi_some_to_some_02.cc    |  2 +-
 4 files changed, 51 insertions(+), 53 deletions(-)

diff --git a/include/deal.II/base/mpi.h b/include/deal.II/base/mpi.h
index 9b59aa1b3d..0f6502153f 100644
--- a/include/deal.II/base/mpi.h
+++ b/include/deal.II/base/mpi.h
@@ -551,6 +551,55 @@ namespace Utilities
                            mpi_communicator, ArrayView<T>(minima, N));
     }
 
+    template<typename T>
+    std::vector<T> all_gather(const MPI_Comm       &comm,
+                              const T &object)
+    {
+#ifndef DEAL_II_WITH_MPI
+      (void)comm;
+      std::vector<T> v(1, object);
+      return v;
+#else
+      const auto n_procs = dealii::Utilities::MPI::n_mpi_processes(comm);
+
+      std::vector<char> buffer = Utilities::pack(object);
+
+      int n_local_data = buffer.size();
+
+      // Vector to store the size of loc_data_array for every process
+      std::vector<int> size_all_data(n_procs,0);
+
+      // Exchanging the size of each buffer
+      MPI_Allgather(&n_local_data, 1, MPI_INT,
+                    &(size_all_data[0]), 1, MPI_INT,
+                    comm);
+
+      // Now computing the the displacement, relative to recvbuf,
+      // at which to store the incoming buffer
+      std::vector<int> rdispls(n_procs);
+      rdispls[0] = 0;
+      for (unsigned int i=1; i < n_procs; ++i)
+        rdispls[i] = rdispls[i-1] + size_all_data[i-1];
+
+      // Step 3: exchange the buffer:
+      std::vector<char> received_unrolled_buffer(rdispls.back() + size_all_data.back());
+
+      MPI_Allgatherv(buffer.data(), n_local_data, MPI_CHAR,
+                     received_unrolled_buffer.data(), size_all_data.data(),
+                     rdispls.data(), MPI_CHAR, comm);
+
+      std::vector<T> received_objects(n_procs);
+      for (unsigned int i= 0; i < n_procs; ++i)
+        {
+          std::vector<char> local_buffer(received_unrolled_buffer.begin()+rdispls[i],
+                                         received_unrolled_buffer.begin()+rdispls[i]+size_all_data[i]);
+          received_objects[i] = Utilities::unpack<T>(local_buffer);
+        }
+
+      return received_objects;
+#endif
+    }
+
     template <typename T>
     std::vector<T>
     gather(const MPI_Comm &comm,
diff --git a/include/deal.II/base/mpi.templates.h b/include/deal.II/base/mpi.templates.h
index 15162ed41c..b3ce6235eb 100644
--- a/include/deal.II/base/mpi.templates.h
+++ b/include/deal.II/base/mpi.templates.h
@@ -271,57 +271,6 @@ namespace Utilities
 
 
 
-    template<typename T>
-    std::vector<T> all_gather(const MPI_Comm       &comm,
-                              const T &object)
-    {
-#ifndef DEAL_II_WITH_MPI
-      (void)comm;
-      std::vector<T> v(1, object);
-      return v;
-#else
-      const auto n_procs = dealii::Utilities::MPI::n_mpi_processes(comm);
-
-      std::vector<char> buffer = Utilities::pack(object);
-
-      int n_local_data = buffer.size();
-
-      // Vector to store the size of loc_data_array for every process
-      std::vector<int> size_all_data(n_procs,0);
-
-      // Exchanging the size of each buffer
-      MPI_Allgather(&n_local_data, 1, MPI_INT,
-                    &(size_all_data[0]), 1, MPI_INT,
-                    comm);
-
-      // Now computing the the displacement, relative to recvbuf,
-      // at which to store the incoming buffer
-      std::vector<int> rdispls(n_procs);
-      rdispls[0] = 0;
-      for (unsigned int i=1; i < n_procs; ++i)
-        rdispls[i] = rdispls[i-1] + size_all_data[i-1];
-
-      // Step 3: exchange the buffer:
-      std::vector<char> received_unrolled_buffer(rdispls.back() + size_all_data.back());
-
-      MPI_Allgatherv(buffer.data(), n_local_data, MPI_CHAR,
-                     received_unrolled_buffer.data(), size_all_data.data(),
-                     rdispls.data(), MPI_CHAR, comm);
-
-      std::vector<T> received_objects(n_procs);
-      for (unsigned int i= 0; i < n_procs; ++i)
-        {
-          std::vector<char> local_buffer(received_unrolled_buffer.begin()+rdispls[i],
-                                         received_unrolled_buffer.begin()+rdispls[i]+size_all_data[i]);
-          received_objects[i] = Utilities::unpack<T>(local_buffer);
-        }
-
-      return received_objects;
-#endif
-    }
-
-
-
     template <typename T>
     T sum (const T &t,
            const MPI_Comm &mpi_communicator)
diff --git a/tests/base/mpi_all_gather_01.cc b/tests/base/mpi_all_gather_01.cc
index 803fe31f20..f996b4092f 100644
--- a/tests/base/mpi_all_gather_01.cc
+++ b/tests/base/mpi_all_gather_01.cc
@@ -18,7 +18,7 @@
 
 #include "../tests.h"
 #include <deal.II/base/point.h>
-#include <deal.II/base/mpi.templates.h>
+#include <deal.II/base/mpi.h>
 #include <vector>
 
 int main(int argc, char *argv[])
diff --git a/tests/base/mpi_some_to_some_02.cc b/tests/base/mpi_some_to_some_02.cc
index e6e7a4e440..8a442b9400 100644
--- a/tests/base/mpi_some_to_some_02.cc
+++ b/tests/base/mpi_some_to_some_02.cc
@@ -20,7 +20,7 @@
 
 #include <deal.II/base/point.h>
 #include <deal.II/base/mpi.templates.h>
-
+#include <deal.II/base/mpi.h>
 #include <vector>
 #include <tuple>
 
-- 
2.39.5