From 304ce7364a65d5844a58ffee1c59617f55176d5b Mon Sep 17 00:00:00 2001
From: Joachim Schoeberl <joachim.schoeberl@tuwien.ac.at>
Date: Sun, 14 Jul 2024 20:38:36 +0200
Subject: [PATCH] mpi-send of 0D-elements

---
 libsrc/meshing/meshclass.cpp | 27 +++++++++++++++++++++++++++
 libsrc/meshing/meshtype.cpp  | 29 +++++++++++++++++++++++++++++
 libsrc/meshing/meshtype.hpp  | 10 +++++++++-
 3 files changed, 65 insertions(+), 1 deletion(-)

diff --git a/libsrc/meshing/meshclass.cpp b/libsrc/meshing/meshclass.cpp
index 85106adb..287066cd 100644
--- a/libsrc/meshing/meshclass.cpp
+++ b/libsrc/meshing/meshclass.cpp
@@ -1810,6 +1810,33 @@ namespace netgen
             archive & copy_el1d;
           }
 
+
+        // sending 0D elements
+        auto copy_el0d  (pointelements);
+        for (auto & el : copy_el0d)
+          {
+            auto & pi = el.pnum;
+            if (pi != PointIndex(PointIndex::INVALID))
+              pi = globnum[pi];
+          }
+        
+        if (comm.Rank() > 0)
+          comm.Send(copy_el0d, 0, 200);
+        else
+          {
+            Array<Element0d> el0di;
+            for (int j = 1; j < comm.Size(); j++)
+              {
+                comm.Recv(el0di, j, 200);
+                for (auto & el : el0di)
+                  copy_el0d += el;
+              }
+            archive & copy_el0d;
+          }
+
+
+
+        
         if (comm.Rank() == 0)
           {
             archive & facedecoding;
diff --git a/libsrc/meshing/meshtype.cpp b/libsrc/meshing/meshtype.cpp
index f5dcfbe1..87c63384 100644
--- a/libsrc/meshing/meshtype.cpp
+++ b/libsrc/meshing/meshtype.cpp
@@ -144,6 +144,35 @@ namespace netgen
 #endif
 
 
+#ifdef PARALLEL
+  NG_MPI_Datatype Element0d :: MyGetMPIType()
+  {
+    static NG_MPI_Datatype type = NG_MPI_DATATYPE_NULL;
+    static NG_MPI_Datatype htype = NG_MPI_DATATYPE_NULL;
+    if (type == NG_MPI_DATATYPE_NULL)
+      {
+	Element0d hel;
+	int blocklen[] = { 1, 1 };
+	NG_MPI_Aint displ[] =
+          { (char*)&hel.pnum - (char*)&hel,
+            (char*)&hel.index - (char*)&hel,
+          };
+	NG_MPI_Datatype types[] = {
+          GetMPIType(hel.pnum), GetMPIType(hel.index)
+        };
+	NG_MPI_Type_create_struct (2, blocklen, displ, types, &htype);
+	NG_MPI_Type_commit ( &htype );
+	NG_MPI_Aint lb, ext;
+	NG_MPI_Type_get_extent (htype, &lb, &ext);
+	// *testout << "lb = " << lb << endl;
+	// *testout << "ext = " << ext << endl;
+	ext = sizeof (Element0d);
+	NG_MPI_Type_create_resized (htype, lb, ext, &type);
+	NG_MPI_Type_commit ( &type );
+      }
+    return type;
+  }
+#endif
 
  void Element0d :: DoArchive (Archive & ar)
  {
diff --git a/libsrc/meshing/meshtype.hpp b/libsrc/meshing/meshtype.hpp
index bf044082..5186572d 100644
--- a/libsrc/meshing/meshtype.hpp
+++ b/libsrc/meshing/meshtype.hpp
@@ -1163,7 +1163,12 @@ namespace netgen
     int index;
     Element0d () = default;
     Element0d (PointIndex _pnum, int _index)
-      : pnum(_pnum), index(_index) { ; } 
+      : pnum(_pnum), index(_index) { ; }
+
+#ifdef PARALLEL
+    static NG_MPI_Datatype MyGetMPIType();
+#endif
+    
     void DoArchive (Archive & ar);
   };
 
@@ -1672,6 +1677,9 @@ namespace ngcore
   template <> struct MPI_typetrait<netgen::Segment> {
     static NG_MPI_Datatype MPIType ()  { return netgen::Segment::MyGetMPIType(); }
   };
+  template <> struct MPI_typetrait<netgen::Element0d> {
+    static NG_MPI_Datatype MPIType ()  { return netgen::Element0d::MyGetMPIType(); }
+  };
 
 }
 #endif