Adding other nstencil classes

src/nstencil_multi.cpp

@@ -0,0 +1,133 @@
+// clang-format off
+/* ----------------------------------------------------------------------
+   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
+   https://www.lammps.org/, Sandia National Laboratories
+   Steve Plimpton, sjplimp@sandia.gov
+
+   Copyright (2003) Sandia Corporation.  Under the terms of Contract
+   DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government retains
+   certain rights in this software.  This software is distributed under
+   the GNU General Public License.
+
+   See the README file in the top-level LAMMPS directory.
+------------------------------------------------------------------------- */
+
+#include "nstencil_multi.h"
+
+using namespace LAMMPS_NS;
+
+/* ---------------------------------------------------------------------- */
+
+template<int HALF, int DIM_3D, int TRI>
+NStencilMulti<HALF, DIM_3D, TRI>::NStencilMulti(LAMMPS *lmp) : NStencil(lmp) {}
+
+/* ---------------------------------------------------------------------- */
+
+template<int HALF, int DIM_3D, int TRI>
+void NStencilMulti<HALF, DIM_3D, TRI>::set_stencil_properties()
+{
+  int n = ncollections;
+  int i, j;
+
+  // FULL
+  // Always look up neighbor using full stencil and neighbor's bin
+  // Stencil cutoff set by i-j cutoff
+
+  // HALF
+  // Cross collections: use full stencil, looking one way through hierarchy
+  // smaller -> larger => use full stencil in larger bin
+  // larger -> smaller => no nstencil required
+  // If cut offs are same, use half stencil
+
+  for (i = 0; i < n; i++) {
+    for (j = 0; j < n; j++) {
+      if (HALF)
+        if (cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;
+
+      flag_skip_multi[i][j] = false;
+      flag_half_multi[i][j] = false;
+      bin_collection_multi[i][j] = j;
+
+      if (HALF) {
+        if (cutcollectionsq[i][i] == cutcollectionsq[j][j]) {
+          flag_half_multi[i][j] = true;
+          bin_collection_multi[i][j] = i;
+        }
+      }
+    }
+  }
+}
+
+/* ----------------------------------------------------------------------
+   create stencil based on bin geometry and cutoff
+------------------------------------------------------------------------- */
+
+template<int HALF, int DIM_3D, int TRI>
+void NStencilMulti<HALF, DIM_3D, TRI>::create()
+{
+  int icollection, jcollection, bin_collection, i, j, k, ns, half_flag;
+  int n = ncollections;
+  double cutsq;
+
+  // For half stencils, only the upper plane is needed
+  int sy_min = sy;
+  int sz_min = sz;
+  if (HALF && (!DIM_3D)) sy_min = 0;
+  if (HALF && DIM_3D) sz_min = 0;
+
+  for (icollection = 0; icollection < n; icollection++) {
+    for (jcollection = 0; jcollection < n; jcollection++) {
+      if (flag_skip_multi[icollection][jcollection]) {
+        nstencil_multi[icollection][jcollection] = 0;
+        continue;
+      }
+
+      ns = 0;
+
+      sx = stencil_sx_multi[icollection][jcollection];
+      sy = stencil_sy_multi[icollection][jcollection];
+      sz = stencil_sz_multi[icollection][jcollection];
+
+      mbinx = stencil_mbinx_multi[icollection][jcollection];
+      mbiny = stencil_mbiny_multi[icollection][jcollection];
+      mbinz = stencil_mbinz_multi[icollection][jcollection];
+
+      bin_collection = bin_collection_multi[icollection][jcollection];
+      cutsq = cutcollectionsq[icollection][jcollection];
+
+      half_flag = flag_half_multi[icollection][jcollection];
+
+      // Half and ortho stencils include central bin first
+      // This preserves the historical order of the neighbor list
+      // as the old npair classes used to separately parse the central bin first
+      if (half_flag && (!TRI)) stencil[nstencil++] = 0;
+
+      for (k = -sz_min; k <= sz; k++) {
+        for (j = -sy_min; j <= sy; j++) {
+          for (i = -sx; i <= sx; i++) {
+
+            // Now only include "upper right" bins for half and ortho stencils
+            if (half_flag && (!DIM_3D) && (!TRI))
+              if (! (j > 0 || (j == 0 && i > 0))) continue;
+            if (half_flag && DIM_3D && (!TRI))
+              if (! (k > 0 || j > 0 || (j == 0 && i > 0))) continue;
+
+            if (bin_distance_multi(i,j,k,bin_collection) < cutsq)
+              stencil_multi[icollection][jcollection][ns++] = k * mbiny * mbinx + j * mbinx + i;
+          }
+        }
+      }
+
+      nstencil_multi[icollection][jcollection] = ns;
+    }
+  }
+}
+
+namespace LAMMPS_NS {
+template class NStencilMulti<0,0,0>;
+template class NStencilMulti<0,1,0>;
+template class NStencilMulti<1,0,0>;
+template class NStencilMulti<1,0,1>;
+template class NStencilMulti<1,1,0>;
+template class NStencilMulti<1,1,1>;
+}