add identical check between 2 grids

src/EXTRA-FIX/fix_ttm_grid.cpp

@@ -368,6 +368,20 @@ void FixTTMGrid::read_electron_temperatures(const std::string &filename)
 
 void FixTTMGrid::reset_grid()
 {
+  // check if new grid partitioning is different on any proc
+  // if not, just return
+
+  int tmp[12];
+  double maxdist = 0.5 * neighbor->skin;
+  Grid3d *gridnew = new Grid3d(lmp, world, nxgrid, nygrid, nzgrid, maxdist, 1, SHIFT,
+			       tmp[0],tmp[1],tmp[2],tmp[3],tmp[4],tmp[5],
+			       tmp[6],tmp[7],tmp[8],tmp[9],tmp[10],tmp[11]);
+  
+  if (grid->identical(gridnew)) {
+    delete gridnew;
+    return;
+  } else delete gridnew;
+  
   // delete grid data which doesn't need to persist from previous to new decomp
 
   memory->destroy(grid_buf1);

src/grid2d.cpp

@@ -352,6 +352,29 @@ void Grid2d::store(int ixlo, int ixhi, int iylo, int iyhi,
 
 /* ---------------------------------------------------------------------- */
 
+int Grid2d::identical(Grid2d *grid2)
+{
+  int inxlo2,inxhi2,inylo2,inyhi2;
+  int outxlo2,outxhi2,outylo2,outyhi2;
+
+  grid2->get_bounds(inxlo2,inxhi2,inylo2,inyhi2);
+  grid2->get_bounds_ghost(outxlo2,outxhi2,outylo2,outyhi2);
+
+  int flag = 0;
+  if (inxlo != inxlo2 || inxhi != inxhi2 ||
+      inylo != inylo2 || inyhi != inyhi2) flag = 1;
+  if (outxlo != outxlo2 || outxhi != outxhi2 ||
+      outylo != outylo2 || outyhi != outyhi2) flag = 1;
+
+  int flagall;
+  MPI_Allreduce(&flag,&flagall,1,MPI_INT,MPI_SUM,gridcomm);
+
+  if (flagall) return 0;
+  return 1;
+}
+
+/* ---------------------------------------------------------------------- */
+
 void Grid2d::get_size(int &nxgrid, int &nygrid)
 {
   nxgrid = nx;
@@ -368,6 +391,16 @@ void Grid2d::get_bounds(int &xlo, int &xhi, int &ylo, int &yhi)
   yhi = inyhi;
 }
 
+/* ---------------------------------------------------------------------- */
+
+void Grid2d::get_bounds_ghost(int &xlo, int &xhi, int &ylo, int &yhi)
+{
+  xlo = outxlo;
+  xhi = outxhi;
+  ylo = outylo;
+  yhi = outyhi;
+}
+
 /* ----------------------------------------------------------------------
    return sizes of two buffers needed for communication
    either on regular grid or procs or irregular tiling

src/grid2d.h

@@ -29,8 +29,10 @@ class Grid2d : protected Pointers {
   Grid2d(class LAMMPS *, MPI_Comm, int, int, int, int, int, int, int, int, int, int,
          int, int, int, int, int);
   ~Grid2d() override;
+  int identical(Grid2d *);
   void get_size(int &, int &);
   void get_bounds(int &, int &, int &, int &);
+  void get_bounds_ghost(int &, int &, int &, int &);
   void setup(int &, int &);
   int ghost_adjacent();
   void forward_comm(int, void *, int, int, int, void *, void *, MPI_Datatype);

src/grid3d.cpp

@@ -381,6 +381,31 @@ void Grid3d::store(int ixlo, int ixhi, int iylo, int iyhi,
 
 /* ---------------------------------------------------------------------- */
 
+int Grid3d::identical(Grid3d *grid2)
+{
+  int inxlo2,inxhi2,inylo2,inyhi2,inzlo2,inzhi2;
+  int outxlo2,outxhi2,outylo2,outyhi2,outzlo2,outzhi2;
+
+  grid2->get_bounds(inxlo2,inxhi2,inylo2,inyhi2,inzlo2,inzhi2);
+  grid2->get_bounds_ghost(outxlo2,outxhi2,outylo2,outyhi2,outzlo2,outzhi2);
+
+  int flag = 0;
+  if (inxlo != inxlo2 || inxhi != inxhi2 ||
+      inylo != inylo2 || inyhi != inyhi2 ||
+      inzlo != inzlo2 || inzhi != inzhi2) flag = 1;
+  if (outxlo != outxlo2 || outxhi != outxhi2 ||
+      outylo != outylo2 || outyhi != outyhi2 ||
+      outzlo != outzlo2 || outzhi != outzhi2) flag = 1;
+
+  int flagall;
+  MPI_Allreduce(&flag,&flagall,1,MPI_INT,MPI_SUM,gridcomm);
+
+  if (flagall) return 0;
+  return 1;
+}
+
+/* ---------------------------------------------------------------------- */
+
 void Grid3d::get_size(int &nxgrid, int &nygrid, int &nzgrid)
 {
   nxgrid = nx;
@@ -401,6 +426,19 @@ void Grid3d::get_bounds(int &xlo, int &xhi, int &ylo, int &yhi,
   zhi = inzhi;
 }
 
+/* ---------------------------------------------------------------------- */
+
+void Grid3d::get_bounds_ghost(int &xlo, int &xhi, int &ylo, int &yhi,
+			      int &zlo, int &zhi)
+{
+  xlo = outxlo;
+  xhi = outxhi;
+  ylo = outylo;
+  yhi = outyhi;
+  zlo = outzlo;
+  zhi = outzhi;
+}
+
 /* ----------------------------------------------------------------------
    return sizes of two buffers needed for communication
    either on regular grid or procs or irregular tiling
@@ -1332,6 +1370,7 @@ void Grid3d::remap_setup(Grid3d *old, int &ngrid1_buf, int &ngrid2_buf)
 void Grid3d::remap_setup_regular(Grid3d *old, int &ngrid1_buf, int &ngrid2_buf)
 {
   // NOTE: when to clean up data structs when multiple remaps occur
+  // NOTE: does a remap also require ghost comm in fix ttm/grid ?
   
   ngrid1_buf = 0;
   ngrid2_buf = 0;

src/grid3d.h

@@ -31,8 +31,10 @@ class Grid3d : protected Pointers {
          int, int, int, int, int, int, int, int, int, int, int, int,
          int, int, int, int, int, int);
   ~Grid3d() override;
+  int identical(Grid3d *);
   void get_size(int &, int &, int &);
   void get_bounds(int &, int &, int &, int &, int &, int &);
+  void get_bounds_ghost(int &, int &, int &, int &, int &, int &);
   void setup(int &, int &);
   int ghost_adjacent();
   void forward_comm(int, void *, int, int, int, void *, void *, MPI_Datatype);