/* ----------------------------------------------------------------------
   LAMMPS - Large-scale Atomic/Molecular Massively Parallel Simulator
   https://www.lammps.org/, Sandia National Laboratories
   LAMMPS development team: developers@lammps.org

   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_half_multi_3d_tri.h"

#include "neigh_list.h"

using namespace LAMMPS_NS;

/* ---------------------------------------------------------------------- */

NStencilHalfMulti3dTri::NStencilHalfMulti3dTri(LAMMPS *lmp) : NStencil(lmp) {}

/* ---------------------------------------------------------------------- */

void NStencilHalfMulti3dTri::set_stencil_properties()
{
  int n = ncollections;
  int i, j;

  // 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 (cutcollectionsq[i][i] > cutcollectionsq[j][j]) continue;

      flag_skip_multi[i][j] = false;

      if (cutcollectionsq[i][i] == cutcollectionsq[j][j]) {
        flag_half_multi[i][j] = true;
        bin_collection_multi[i][j] = i;
      } else {
        flag_half_multi[i][j] = false;
        bin_collection_multi[i][j] = j;
      }
    }
  }
}

/* ----------------------------------------------------------------------
   create stencils based on bin geometry and cutoff
------------------------------------------------------------------------- */

void NStencilHalfMulti3dTri::create()
{
  int icollection, jcollection, bin_collection, i, j, k, ns;
  int n = ncollections;
  double cutsq;

  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];

      if (flag_half_multi[icollection][jcollection]) {
        for (k = 0; k <= sz; k++)
          for (j = -sy; j <= sy; j++)
            for (i = -sx; i <= sx; i++)
              if (bin_distance_multi(i, j, k, bin_collection) < cutsq)
                stencil_multi[icollection][jcollection][ns++] = k * mbiny * mbinx + j * mbinx + i;
      } else {
        for (k = -sz; k <= sz; k++)
          for (j = -sy; j <= sy; j++)
            for (i = -sx; i <= sx; i++)
              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;
    }
  }
}