/*
 * Copyright (c) 2014, Sandia Corporation.
 * Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
 * the U.S. Government retains certain rights in this software.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *
 *     * Redistributions in binary form must reproduce the above
 *       copyright notice, this list of conditions and the following
 *       disclaimer in the documentation and/or other materials provided
 *       with the distribution.
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 *     * Neither the name of Sandia Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */

#include "defs.h"    // for min
#include "params.h"  // for MAXSETS
#include "structs.h" // for set_info

int divide_procs(int              architecture, /* 0 => hypercube, d => d-dimensional mesh */
                 int              ndims,        /* normal dimension of each cut */
                 int              ndims_tot,    /* total number of hypercube dimensions */
                 struct set_info *info_set,     /* data for all sets */
                 struct set_info *divide_set,   /* data for set being divided */
                 int *            subsets,      /* subsets to be created */
                 int              inert,        /* using inertial method? */
                 int *            pndims_real,  /* actual ndims for this cut */
                 int *            pnsets_real,  /* # sets created by this cut */
                 int *            pstriping,    /* cut in single direction? */
                 int *            cut_dirs,     /* direction of each cut if mesh */
                 int *            mesh_dims,    /* size of full mesh */
                 int              hops_special[][MAXSETS] /* hop matrix for nonstandard cases */
                 )
{
  int nsets_real = -1; /* number of sets to divide into */
  int ndims_real = -1; /* number of eigenvectors to use */
  int striping   = -1; /* cut in single direction? */
  int flag       = -1; /* unusual partition => use special hops */
  int ndim_poss;       /* largest dimensionality possible */
  int idims;           /* true dimensionality of subgrid */
  int i;               /* loop counter */
  int define_submeshes(), define_subcubes();

  if (architecture > 0) { /* Mesh, complicated case. */
    nsets_real = divide_set->span[0] * divide_set->span[1] * divide_set->span[2];
    nsets_real = min(1 << ndims, nsets_real);
    ndims_real = ndims;
    while (1 << ndims_real > nsets_real)
      --ndims_real;

    ndim_poss = 0;
    idims     = 0;
    for (i = 0; i < 3; i++) {
      if (divide_set->span[i] >= 2) {
        ndim_poss++;
        idims++;
      }
      if (divide_set->span[i] >= 4)
        ndim_poss++;
      if (divide_set->span[i] >= 8)
        ndim_poss++;
    }
    ndims_real = min(ndim_poss, ndims_real);

    if (idims > 1) {
      nsets_real = 1 << ndims_real;
    }

    flag = define_submeshes(nsets_real, architecture, mesh_dims, divide_set, info_set, subsets,
                            inert, &striping, cut_dirs, hops_special);
    if (striping) {
      ndims_real = 1;
    }
  }

  else if (architecture == 0) { /* Hypercube, easy case. */
    ndims_real = min(ndims, divide_set->ndims);
    nsets_real = 1 << ndims_real;

    flag = define_subcubes(nsets_real, ndims_tot, ndims_real, divide_set, info_set, subsets, inert,
                           &striping, hops_special);

    if (striping)
      ndims_real = 1;
  }

  *pndims_real = ndims_real;
  *pnsets_real = nsets_real;
  *pstriping   = striping;

  return (flag);
}
