scheduler.c

/*******************************************************************************
 * This file is part of SWIFT.
 * Copyright (c) 2012 Pedro Gonnet (pedro.gonnet@durham.ac.uk)
 *                    Matthieu Schaller (matthieu.schaller@durham.ac.uk)
 *               2016 Peter W. Draper (p.w.draper@durham.ac.uk)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/

/* Config parameters. */
#include "../config.h"

/* Some standard headers. */
#include <limits.h>
#include <math.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* MPI headers. */
#ifdef WITH_MPI
#include <mpi.h>
#endif

/* This object's header. */
#include "scheduler.h"

/* Local headers. */
#include "atomic.h"
#include "cycle.h"
#include "engine.h"
#include "error.h"
#include "intrinsics.h"
#include "kernel_hydro.h"
#include "queue.h"
#include "sort_part.h"
#include "space.h"
#include "space_getsid.h"
#include "task.h"
#include "timers.h"
#include "version.h"

/**
 * @brief Re-set the list of active tasks.
 */
void scheduler_clear_active(struct scheduler *s) { s->active_count = 0; }

/**
 * @brief Add an unlock_task to the given task.
 *
 * @param s The #scheduler.
 * @param ta The unlocking #task.
 * @param tb The #task that will be unlocked.
 */
void scheduler_addunlock(struct scheduler *s, struct task *ta,
                         struct task *tb) {
#ifdef SWIFT_DEBUG_CHECKS
  if (ta == NULL) error("Unlocking task is NULL.");
  if (tb == NULL) error("Unlocked task is NULL.");
#endif

  /* Get an index at which to store this unlock. */
  const int ind = atomic_inc(&s->nr_unlocks);

  /* Does the buffer need to be grown? */
  if (ind == s->size_unlocks) {
    /* Allocate the new buffer. */
    struct task **unlocks_new;
    int *unlock_ind_new;
    const int size_unlocks_new = s->size_unlocks * 2;
    if ((unlocks_new = (struct task **)malloc(sizeof(struct task *) *
                                              size_unlocks_new)) == NULL ||
        (unlock_ind_new = (int *)malloc(sizeof(int) * size_unlocks_new)) ==
            NULL)
      error("Failed to re-allocate unlocks.");

    /* Wait for all writes to the old buffer to complete. */
    while (s->completed_unlock_writes < ind)
      ;

    /* Copy the buffers. */
    memcpy(unlocks_new, s->unlocks, sizeof(struct task *) * ind);
    memcpy(unlock_ind_new, s->unlock_ind, sizeof(int) * ind);
    free(s->unlocks);
    free(s->unlock_ind);
    s->unlocks = unlocks_new;
    s->unlock_ind = unlock_ind_new;

    /* Publish the new buffer size. */
    s->size_unlocks = size_unlocks_new;
  }

  /* Wait for there to actually be space at my index. */
  while (ind > s->size_unlocks)
    ;

  /* Write the unlock to the scheduler. */
  s->unlocks[ind] = tb;
  s->unlock_ind[ind] = ta - s->tasks;
  atomic_inc(&s->completed_unlock_writes);
}

/**
 * @brief Write a dot file with the task dependencies.
 *
 * Run plot_task_dependencies.sh for an example of how to use it
 * to generate the figure.
 *
 * @param s The #scheduler we are working in.
 * @param verbose Are we verbose about this?
 */
void scheduler_write_dependencies(struct scheduler *s, int verbose) {

  const ticks tic = getticks();

  /* Conservative number of dependencies per task type */
  const int max_nber_dep = 128;

  /* Number of possible relations between tasks */
  const int nber_relation =
      2 * task_type_count * task_subtype_count * max_nber_dep;

  /* To get the table of max_nber_dep for a task:
   * ind = (ta * task_subtype_count + sa) * max_nber_dep * 2
   * where ta is the value of task_type and sa is the value of
   * task_subtype  */
  int *table = (int *)malloc(nber_relation * sizeof(int));
  if (table == NULL)
    error("Error allocating memory for task-dependency graph.");

  /* Reset everything */
  for (int i = 0; i < nber_relation; i++) table[i] = -1;

  /* Create file */
  char filename[200] = "dependency_graph.dot";
  FILE *f = fopen(filename, "w");
  if (f == NULL) error("Error opening dependency graph file.");

  /* Write header */
  fprintf(f, "digraph task_dep {\n");
  fprintf(f, "label=\"Task dependencies for SWIFT %s\";\n", git_revision());
  fprintf(f, "\t compound=true;\n");
  fprintf(f, "\t ratio=0.66;\n");
  fprintf(f, "\t node[nodesep=0.15];\n");

  /* loop over all tasks */
  for (int i = 0; i < s->nr_tasks; i++) {
    const struct task *ta = &s->tasks[i];

    /* and their dependencies */
    for (int j = 0; j < ta->nr_unlock_tasks; j++) {
      const struct task *tb = ta->unlock_tasks[j];

      /* check if dependency already written */
      int written = 0;

      /* Current index */
      int ind = ta->type * task_subtype_count + ta->subtype;
      ind *= 2 * max_nber_dep;

      int k = 0;
      int *cur = &table[ind];
      while (k < max_nber_dep) {

        /* not written yet */
        if (cur[0] == -1) {
          cur[0] = tb->type;
          cur[1] = tb->subtype;
          break;
        }

        /* already written */
        if (cur[0] == tb->type && cur[1] == tb->subtype) {
          written = 1;
          break;
        }

        k += 1;
        cur = &cur[3];
      }

      /* max_nber_dep is too small */
      if (k == max_nber_dep)
        error("Not enough memory, please increase max_nber_dep");

      /* Not written yet => write it */
      if (!written) {

        /* text to write */
        char ta_name[200];
        char tb_name[200];

        /* construct line */
        if (ta->subtype == task_subtype_none)
          sprintf(ta_name, "%s", taskID_names[ta->type]);
        else
          sprintf(ta_name, "\"%s %s\"", taskID_names[ta->type],
                  subtaskID_names[ta->subtype]);

        if (tb->subtype == task_subtype_none)
          sprintf(tb_name, "%s", taskID_names[tb->type]);
        else
          sprintf(tb_name, "\"%s %s\"", taskID_names[tb->type],
                  subtaskID_names[tb->subtype]);

        /* Write to the ffile */
        fprintf(f, "\t %s->%s;\n", ta_name, tb_name);

        /* Change colour of implicit tasks */
        if (ta->implicit)
          fprintf(f, "\t %s [style = filled];\n\t %s [color = lightgrey];\n",
                  ta_name, ta_name);
        if (tb->implicit)
          fprintf(f, "\t %s [style = filled];\n\t %s [color = lightgrey];\n",
                  tb_name, tb_name);

        /* Change shape of MPI communications */
        if (ta->type == task_type_send || ta->type == task_type_recv)
          fprintf(f, "\t \"%s %s\" [shape = diamond];\n",
                  taskID_names[ta->type], subtaskID_names[ta->subtype]);
        if (tb->type == task_type_send || tb->type == task_type_recv)
          fprintf(f, "\t \"%s %s\" [shape = diamond];\n",
                  taskID_names[tb->type], subtaskID_names[tb->subtype]);
      }
    }
  }

  int density_cluster[4] = {0};
  int gradient_cluster[4] = {0};
  int force_cluster[4] = {0};
  int gravity_cluster[5] = {0};
  int stars_density_cluster[4] = {0};

  /* Check whether we need to construct a group of tasks */
  for (int type = 0; type < task_type_count; ++type) {

    for (int subtype = 0; subtype < task_subtype_count; ++subtype) {

      const int ind = 2 * (type * task_subtype_count + subtype) * max_nber_dep;

      /* Does this task/sub-task exist? */
      if (table[ind] != -1) {

        for (int k = 0; k < 4; ++k) {
          if (type == task_type_self + k && subtype == task_subtype_density)
            density_cluster[k] = 1;
          if (type == task_type_self + k && subtype == task_subtype_gradient)
            gradient_cluster[k] = 1;
          if (type == task_type_self + k && subtype == task_subtype_force)
            force_cluster[k] = 1;
          if (type == task_type_self + k && subtype == task_subtype_grav)
            gravity_cluster[k] = 1;
	  if (type == task_type_self + k && subtype == task_subtype_stars_density)
	    stars_density_cluster[k] = 1;
        }
        if (type == task_type_grav_mesh) gravity_cluster[2] = 1;
        if (type == task_type_grav_long_range) gravity_cluster[3] = 1;
        if (type == task_type_grav_mm) gravity_cluster[4] = 1;
      }
    }
  }

  /* Make a cluster for the density tasks */
  fprintf(f, "\t subgraph cluster0{\n");
  fprintf(f, "\t\t label=\"\";\n");
  for (int k = 0; k < 4; ++k)
    if (density_cluster[k])
      fprintf(f, "\t\t \"%s %s\";\n", taskID_names[task_type_self + k],
              subtaskID_names[task_subtype_density]);
  fprintf(f, "\t};\n");

  /* Make a cluster for the force tasks */
  fprintf(f, "\t subgraph cluster1{\n");
  fprintf(f, "\t\t label=\"\";\n");
  for (int k = 0; k < 4; ++k)
    if (force_cluster[k])
      fprintf(f, "\t\t \"%s %s\";\n", taskID_names[task_type_self + k],
              subtaskID_names[task_subtype_force]);
  fprintf(f, "\t};\n");

  /* Make a cluster for the gradient tasks */
  fprintf(f, "\t subgraph cluster2{\n");
  fprintf(f, "\t\t label=\"\";\n");
  for (int k = 0; k < 4; ++k)
    if (gradient_cluster[k])
      fprintf(f, "\t\t \"%s %s\";\n", taskID_names[task_type_self + k],
              subtaskID_names[task_subtype_gradient]);
  fprintf(f, "\t};\n");

  /* Make a cluster for the gravity tasks */
  fprintf(f, "\t subgraph cluster3{\n");
  fprintf(f, "\t\t label=\"\";\n");
  for (int k = 0; k < 2; ++k)
    if (gravity_cluster[k])
      fprintf(f, "\t\t \"%s %s\";\n", taskID_names[task_type_self + k],
              subtaskID_names[task_subtype_grav]);
  if (gravity_cluster[2])
    fprintf(f, "\t\t %s;\n", taskID_names[task_type_grav_mesh]);
  if (gravity_cluster[3])
    fprintf(f, "\t\t %s;\n", taskID_names[task_type_grav_long_range]);
  if (gravity_cluster[4])
    fprintf(f, "\t\t %s;\n", taskID_names[task_type_grav_mm]);
  fprintf(f, "\t};\n");

  /* Make a cluster for the density tasks */
  fprintf(f, "\t subgraph cluster4{\n");
  fprintf(f, "\t\t label=\"\";\n");
  for (int k = 0; k < 4; ++k)
    if (stars_density_cluster[k])
      fprintf(f, "\t\t \"%s %s\";\n", taskID_names[task_type_self + k],
              subtaskID_names[task_subtype_stars_density]);
  fprintf(f, "\t};\n");

  /* Be clean */
  fprintf(f, "}");
  fclose(f);
  free(table);

  if (verbose)
    message("Printing task graph took %.3f %s.",
            clocks_from_ticks(getticks() - tic), clocks_getunit());
}

/**
 * @brief Split a hydrodynamic task if too large.
 *
 * @param t The #task
 * @param s The #scheduler we are working in.
 */
static void scheduler_splittask_hydro(struct task *t, struct scheduler *s) {

  /* Iterate on this task until we're done with it. */
  int redo = 1;
  while (redo) {

    /* Reset the redo flag. */
    redo = 0;

    /* Non-splittable task? */
    if ((t->ci == NULL) || (t->type == task_type_pair && t->cj == NULL) ||
        t->ci->count == 0 || (t->cj != NULL && t->cj->count == 0)) {
      t->type = task_type_none;
      t->subtype = task_subtype_none;
      t->cj = NULL;
      t->skip = 1;
      break;
    }

    /* Self-interaction? */
    if (t->type == task_type_self) {

      /* Get a handle on the cell involved. */
      struct cell *ci = t->ci;

      /* Foreign task? */
      if (ci->nodeID != s->nodeID) {
        t->skip = 1;
        break;
      }

      /* Is this cell even split and the task does not violate h ? */
      if (cell_can_split_self_hydro_task(ci)) {

        /* Make a sub? */
        if (scheduler_dosub && ci->count < space_subsize_self_hydro) {

          /* convert to a self-subtask. */
          t->type = task_type_sub_self;

          /* Otherwise, make tasks explicitly. */
        } else {

          /* Take a step back (we're going to recycle the current task)... */
          redo = 1;

          /* Add the self tasks. */
          int first_child = 0;
          while (ci->progeny[first_child] == NULL) first_child++;
          t->ci = ci->progeny[first_child];
          for (int k = first_child + 1; k < 8; k++)
            if (ci->progeny[k] != NULL && ci->progeny[k]->count)
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_self, t->subtype, 0, 0,
                                    ci->progeny[k], NULL),
                  s);

          /* Make a task for each pair of progeny */
          for (int j = 0; j < 8; j++)
            if (ci->progeny[j] != NULL && ci->progeny[j]->count)
              for (int k = j + 1; k < 8; k++)
                if (ci->progeny[k] != NULL && ci->progeny[k]->count)
                  scheduler_splittask_hydro(
                      scheduler_addtask(s, task_type_pair, t->subtype,
                                        sub_sid_flag[j][k], 0, ci->progeny[j],
                                        ci->progeny[k]),
                      s);
        }
      } /* Cell is split */

    } /* Self interaction */

    /* Pair interaction? */
    else if (t->type == task_type_pair) {

      /* Get a handle on the cells involved. */
      struct cell *ci = t->ci;
      struct cell *cj = t->cj;

      /* Foreign task? */
      if (ci->nodeID != s->nodeID && cj->nodeID != s->nodeID) {
        t->skip = 1;
        break;
      }

      /* Get the sort ID, use space_getsid and not t->flags
         to make sure we get ci and cj swapped if needed. */
      double shift[3];
      const int sid = space_getsid(s->space, &ci, &cj, shift);

      /* Should this task be split-up? */
      if (cell_can_split_pair_hydro_task(ci) &&
          cell_can_split_pair_hydro_task(cj)) {

        /* Replace by a single sub-task? */
        if (scheduler_dosub && /* Use division to avoid integer overflow. */
            ci->count * sid_scale[sid] < space_subsize_pair_hydro / cj->count &&
            !sort_is_corner(sid)) {

          /* Make this task a sub task. */
          t->type = task_type_sub_pair;

          /* Otherwise, split it. */
        } else {

          /* Take a step back (we're going to recycle the current task)... */
          redo = 1;

          /* For each different sorting type... */
          switch (sid) {

            case 0: /* (  1 ,  1 ,  1 ) */
              t->ci = ci->progeny[7];
              t->cj = cj->progeny[0];
              t->flags = 0;
              break;

            case 1: /* (  1 ,  1 ,  0 ) */
              t->ci = ci->progeny[6];
              t->cj = cj->progeny[0];
              t->flags = 1;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 1, 0,
                                    ci->progeny[7], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 0, 0,
                                    ci->progeny[6], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              break;

            case 2: /* (  1 ,  1 , -1 ) */
              t->ci = ci->progeny[6];
              t->cj = cj->progeny[1];
              t->flags = 2;
              break;

            case 3: /* (  1 ,  0 ,  1 ) */
              t->ci = ci->progeny[5];
              t->cj = cj->progeny[0];
              t->flags = 3;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 3, 0,
                                    ci->progeny[7], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 0, 0,
                                    ci->progeny[5], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 6, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              break;

            case 4: /* (  1 ,  0 ,  0 ) */
              t->ci = ci->progeny[4];
              t->cj = cj->progeny[0];
              t->flags = 4;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 5, 0,
                                    ci->progeny[5], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[6], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 3, 0,
                                    ci->progeny[4], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 4, 0,
                                    ci->progeny[5], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 6, 0,
                                    ci->progeny[6], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[7], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 1, 0,
                                    ci->progeny[4], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[5], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 4, 0,
                                    ci->progeny[6], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 5, 0,
                                    ci->progeny[7], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 0, 0,
                                    ci->progeny[4], cj->progeny[3]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 1, 0,
                                    ci->progeny[5], cj->progeny[3]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 3, 0,
                                    ci->progeny[6], cj->progeny[3]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 4, 0,
                                    ci->progeny[7], cj->progeny[3]),
                  s);
              break;

            case 5: /* (  1 ,  0 , -1 ) */
              t->ci = ci->progeny[4];
              t->cj = cj->progeny[1];
              t->flags = 5;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 5, 0,
                                    ci->progeny[6], cj->progeny[3]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[4], cj->progeny[3]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[6], cj->progeny[1]),
                  s);
              break;

            case 6: /* (  1 , -1 ,  1 ) */
              t->ci = ci->progeny[5];
              t->cj = cj->progeny[2];
              t->flags = 6;
              break;

            case 7: /* (  1 , -1 ,  0 ) */
              t->ci = ci->progeny[4];
              t->cj = cj->progeny[3];
              t->flags = 6;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[5], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[4], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[5], cj->progeny[3]),
                  s);
              break;

            case 8: /* (  1 , -1 , -1 ) */
              t->ci = ci->progeny[4];
              t->cj = cj->progeny[3];
              t->flags = 8;
              break;

            case 9: /* (  0 ,  1 ,  1 ) */
              t->ci = ci->progeny[3];
              t->cj = cj->progeny[0];
              t->flags = 9;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 9, 0,
                                    ci->progeny[7], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 0, 0,
                                    ci->progeny[3], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              break;

            case 10: /* (  0 ,  1 ,  0 ) */
              t->ci = ci->progeny[2];
              t->cj = cj->progeny[0];
              t->flags = 10;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 11, 0,
                                    ci->progeny[3], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[6], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 6, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 9, 0,
                                    ci->progeny[2], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 10, 0,
                                    ci->progeny[3], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[6], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 7, 0,
                                    ci->progeny[7], cj->progeny[1]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 1, 0,
                                    ci->progeny[2], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[3], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 10, 0,
                                    ci->progeny[6], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 11, 0,
                                    ci->progeny[7], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 0, 0,
                                    ci->progeny[2], cj->progeny[5]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 1, 0,
                                    ci->progeny[3], cj->progeny[5]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 9, 0,
                                    ci->progeny[6], cj->progeny[5]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 10, 0,
                                    ci->progeny[7], cj->progeny[5]),
                  s);
              break;

            case 11: /* (  0 ,  1 , -1 ) */
              t->ci = ci->progeny[2];
              t->cj = cj->progeny[1];
              t->flags = 11;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 11, 0,
                                    ci->progeny[6], cj->progeny[5]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[2], cj->progeny[5]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 6, 0,
                                    ci->progeny[6], cj->progeny[1]),
                  s);
              break;

            case 12: /* (  0 ,  0 ,  1 ) */
              t->ci = ci->progeny[1];
              t->cj = cj->progeny[0];
              t->flags = 12;
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 11, 0,
                                    ci->progeny[3], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 5, 0,
                                    ci->progeny[5], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 2, 0,
                                    ci->progeny[7], cj->progeny[0]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 9, 0,
                                    ci->progeny[1], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 12, 0,
                                    ci->progeny[3], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 8, 0,
                                    ci->progeny[5], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 5, 0,
                                    ci->progeny[7], cj->progeny[2]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 3, 0,
                                    ci->progeny[1], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 6, 0,
                                    ci->progeny[3], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 12, 0,
                                    ci->progeny[5], cj->progeny[4]),
                  s);
              scheduler_splittask_hydro(
                  scheduler_addtask(s, task_type_pair, t->subtype, 11, 0,