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41 results

cell.h

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  • test125cells.c 26.54 KiB
    /*******************************************************************************
     * This file is part of SWIFT.
     * Copyright (C) 2016 Matthieu Schaller (matthieu.schaller@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 <fenv.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <unistd.h>
    
    /* Local headers. */
    #include "swift.h"
    
    #if defined(WITH_VECTORIZATION)
    #define DOSELF2 runner_doself2_force_vec
    #define DOPAIR2 runner_dopair2_branch_force
    #define DOSELF2_NAME "runner_doself2_force_vec"
    #define DOPAIR2_NAME "runner_dopair2_force_vec"
    #endif
    
    #ifndef DOSELF2
    #define DOSELF2 runner_doself2_force
    #define DOSELF2_NAME "runner_doself2_density"
    #endif
    
    #ifndef DOPAIR2
    #define DOPAIR2 runner_dopair2_branch_force
    #define DOPAIR2_NAME "runner_dopair2_force"
    #endif
    
    #define NODE_ID 0
    
    enum velocity_field {
      velocity_zero,
      velocity_const,
      velocity_divergent,
      velocity_rotating
    };
    
    enum pressure_field { pressure_const, pressure_gradient, pressure_divergent };
    
    void set_velocity(struct part *part, enum velocity_field vel, float size) {
    
      switch (vel) {
        case velocity_zero:
          part->v[0] = 0.f;
          part->v[1] = 0.f;
          part->v[2] = 0.f;
          break;
        case velocity_const:
          part->v[0] = 1.f;
          part->v[1] = 0.f;
          part->v[2] = 0.f;
          break;
        case velocity_divergent:
          part->v[0] = part->x[0] - 2.5 * size;
          part->v[1] = part->x[1] - 2.5 * size;
          part->v[2] = part->x[2] - 2.5 * size;
          break;
        case velocity_rotating:
          part->v[0] = part->x[1];
          part->v[1] = -part->x[0];
          part->v[2] = 0.f;
          break;
      }
    }
    
    float get_pressure(double x[3], enum pressure_field press, float size) {
    
      float r2 = 0.;
      float dx[3] = {0.f};
    
      switch (press) {
        case pressure_const:
          return 1.5f;
          break;
        case pressure_gradient:
          return 1.5f * x[0]; /* gradient along x */
          break;
        case pressure_divergent:
          dx[0] = x[0] - 2.5 * size;
          dx[1] = x[1] - 2.5 * size;
          dx[2] = x[2] - 2.5 * size;
          r2 = dx[0] * dx[0] + dx[1] * dx[1] + dx[2] * dx[2];
          return sqrt(r2) + 1.5f;
          break;
      }
      return 0.f;
    }
    
    void set_energy_state(struct part *part, enum pressure_field press, float size,
                          float density) {
    
      const float pressure = get_pressure(part->x, press, size);
    
    #if defined(GADGET2_SPH)
      part->entropy = pressure / pow_gamma(density);
    #elif defined(HOPKINS_PE_SPH)
      part->entropy = pressure / pow_gamma(density);
    #elif defined(DEFAULT_SPH)
      part->u = pressure / (hydro_gamma_minus_one * density);
    #elif defined(MINIMAL_SPH)
      part->u = pressure / (hydro_gamma_minus_one * density);
    #elif defined(MINIMAL_MULTI_MAT_SPH)
      part->u = pressure / (hydro_gamma_minus_one * density);
    #elif defined(GIZMO_SPH) || defined(SHADOWFAX_SPH)
      part->primitives.P = pressure;
    #else
      error("Need to define pressure here !");
    #endif
    }
    
    struct solution_part {
    
      long long id;
      double x[3];
      float v[3];
      float a_hydro[3];
      float h;
      float rho;
      float div_v;
      float S;
      float u;
      float P;
      float c;
      float h_dt;
      float v_sig;
      float S_dt;
      float u_dt;
    };
    
    void get_solution(const struct cell *main_cell, struct solution_part *solution,
                      float density, enum velocity_field vel,
                      enum pressure_field press, float size) {
    
      for (int i = 0; i < main_cell->count; ++i) {
    
        solution[i].id = main_cell->parts[i].id;
    
        solution[i].x[0] = main_cell->parts[i].x[0];
        solution[i].x[1] = main_cell->parts[i].x[1];
        solution[i].x[2] = main_cell->parts[i].x[2];
    
        solution[i].v[0] = main_cell->parts[i].v[0];
        solution[i].v[1] = main_cell->parts[i].v[1];
        solution[i].v[2] = main_cell->parts[i].v[2];
    
        solution[i].h = main_cell->parts[i].h;
    
        solution[i].rho = density;
    
        solution[i].P = get_pressure(solution[i].x, press, size);
        solution[i].u = solution[i].P / (solution[i].rho * hydro_gamma_minus_one);
        solution[i].S = solution[i].P / pow_gamma(solution[i].rho);
        solution[i].c = sqrt(hydro_gamma * solution[i].P / solution[i].rho);
    
        if (vel == velocity_divergent)
          solution[i].div_v = 3.f;
        else
          solution[i].div_v = 0.f;
    
        solution[i].h_dt = solution[i].h * solution[i].div_v / 3.;
    
        float gradP[3] = {0.f};
        if (press == pressure_gradient) {
          gradP[0] = 1.5f;
          gradP[1] = 0.f;
          gradP[2] = 0.f;
        } else if (press == pressure_divergent) {
          float dx[3];
          dx[0] = solution[i].x[0] - 2.5 * size;
          dx[1] = solution[i].x[1] - 2.5 * size;
          dx[2] = solution[i].x[2] - 2.5 * size;
          float r = sqrt(dx[0] * dx[0] + dx[1] * dx[1] + dx[2] * dx[2]);
          if (r > 0.) {
            gradP[0] = dx[0] / r;
            gradP[1] = dx[1] / r;
            gradP[2] = dx[2] / r;
          }
        }
    
        solution[i].a_hydro[0] = -gradP[0] / solution[i].rho;
        solution[i].a_hydro[1] = -gradP[1] / solution[i].rho;
        solution[i].a_hydro[2] = -gradP[2] / solution[i].rho;
    
        solution[i].v_sig = 2.f * solution[i].c;
    
        solution[i].S_dt = 0.f;
        solution[i].u_dt = -(solution[i].P / solution[i].rho) * solution[i].div_v;
      }
    }
    
    void reset_particles(struct cell *c, struct hydro_space *hs,
                         enum velocity_field vel, enum pressure_field press,
                         float size, float density) {
    
      for (int i = 0; i < c->count; ++i) {
    
        struct part *p = &c->parts[i];
    
        set_velocity(p, vel, size);
        set_energy_state(p, press, size, density);
    
        hydro_init_part(p, hs);
    
    #if defined(GIZMO_SPH) || defined(SHADOWFAX_SPH)
        float volume = p->conserved.mass / density;
    #if defined(GIZMO_SPH)
        p->geometry.volume = volume;
    #else
        p->cell.volume = volume;
    #endif
        p->primitives.rho = density;
        p->primitives.v[0] = p->v[0];
        p->primitives.v[1] = p->v[1];
        p->primitives.v[2] = p->v[2];
        p->conserved.momentum[0] = p->conserved.mass * p->v[0];
        p->conserved.momentum[1] = p->conserved.mass * p->v[1];
        p->conserved.momentum[2] = p->conserved.mass * p->v[2];
        p->conserved.energy =
            p->primitives.P / hydro_gamma_minus_one * volume +
            0.5f * (p->conserved.momentum[0] * p->conserved.momentum[0] +
                    p->conserved.momentum[1] * p->conserved.momentum[1] +
                    p->conserved.momentum[2] * p->conserved.momentum[2]) /
                p->conserved.mass;
    #endif
      }
    }
    
    /**
     * @brief Constructs a cell and all of its particle in a valid state prior to
     * a SPH time-step.
     *
     * @param n The cube root of the number of particles.
     * @param offset The position of the cell offset from (0,0,0).
     * @param size The cell size.
     * @param h The smoothing length of the particles in units of the inter-particle
     * separation.
     * @param density The density of the fluid.
     * @param partId The running counter of IDs.
     * @param pert The perturbation to apply to the particles in the cell in units
     *of the inter-particle separation.
     * @param vel The type of velocity field.
     * @param press The type of pressure field.
     */
    struct cell *make_cell(size_t n, const double offset[3], double size, double h,
                           double density, long long *partId, double pert,
                           enum velocity_field vel, enum pressure_field press) {
    
      const size_t count = n * n * n;
      const double volume = size * size * size;
      struct cell *cell = malloc(sizeof(struct cell));
      bzero(cell, sizeof(struct cell));
    
      if (posix_memalign((void **)&cell->parts, part_align,
                         count * sizeof(struct part)) != 0)
        error("couldn't allocate particles, no. of particles: %d", (int)count);
      if (posix_memalign((void **)&cell->xparts, xpart_align,
                         count * sizeof(struct xpart)) != 0)
        error("couldn't allocate particles, no. of x-particles: %d", (int)count);
      bzero(cell->parts, count * sizeof(struct part));
      bzero(cell->xparts, count * sizeof(struct xpart));
    
      float h_max = 0.f;
    
      /* Construct the parts */
      struct part *part = cell->parts;
      struct xpart *xpart = cell->xparts;
      for (size_t x = 0; x < n; ++x) {
        for (size_t y = 0; y < n; ++y) {
          for (size_t z = 0; z < n; ++z) {
            part->x[0] =
                offset[0] +
                size * (x + 0.5 + random_uniform(-0.5, 0.5) * pert) / (float)n;
            part->x[1] =
                offset[1] +
                size * (y + 0.5 + random_uniform(-0.5, 0.5) * pert) / (float)n;
            part->x[2] =
                offset[2] +
                size * (z + 0.5 + random_uniform(-0.5, 0.5) * pert) / (float)n;
            part->h = size * h / (float)n;
            h_max = fmax(h_max, part->h);
    
    #if defined(GIZMO_SPH) || defined(SHADOWFAX_SPH)
            part->conserved.mass = density * volume / count;
    #else
            part->mass = density * volume / count;
    #endif
    
            set_velocity(part, vel, size);
            set_energy_state(part, press, size, density);
    
            hydro_first_init_part(part, xpart);
    
            part->id = ++(*partId);
            part->time_bin = 1;
    
    #if defined(GIZMO_SPH)
            part->geometry.volume = part->conserved.mass / density;
            part->primitives.rho = density;
            part->primitives.v[0] = part->v[0];
            part->primitives.v[1] = part->v[1];
            part->primitives.v[2] = part->v[2];
            part->conserved.momentum[0] = part->conserved.mass * part->v[0];
            part->conserved.momentum[1] = part->conserved.mass * part->v[1];
            part->conserved.momentum[2] = part->conserved.mass * part->v[2];
            part->conserved.energy =
                part->primitives.P / hydro_gamma_minus_one * volume +
                0.5f * (part->conserved.momentum[0] * part->conserved.momentum[0] +
                        part->conserved.momentum[1] * part->conserved.momentum[1] +
                        part->conserved.momentum[2] * part->conserved.momentum[2]) /
                    part->conserved.mass;
    #endif
    
    #ifdef SWIFT_DEBUG_CHECKS
            part->ti_drift = 8;
            part->ti_kick = 8;
    #endif
    
            ++part;
            ++xpart;
          }
        }
      }
    
      /* Cell properties */
      cell->split = 0;
      cell->h_max = h_max;
      cell->count = count;
      cell->gcount = 0;
      cell->dx_max_part = 0.;
      cell->dx_max_sort = 0.;
      cell->width[0] = size;
      cell->width[1] = size;
      cell->width[2] = size;
      cell->loc[0] = offset[0];
      cell->loc[1] = offset[1];
      cell->loc[2] = offset[2];
    
      cell->ti_old_part = 8;
      cell->ti_hydro_end_min = 8;
      cell->ti_hydro_end_max = 8;
      cell->nodeID = NODE_ID;
    
      // shuffle_particles(cell->parts, cell->count);
    
      cell->sorted = 0;
      for (int k = 0; k < 13; k++) cell->sort[k] = NULL;
    
      return cell;
    }
    
    void clean_up(struct cell *ci) {
      free(ci->parts);
      free(ci->xparts);
      for (int k = 0; k < 13; k++)
        if (ci->sort[k] != NULL) free(ci->sort[k]);
      free(ci);
    }
    
    /**
     * @brief Dump all the particles to a file
     */
    void dump_particle_fields(char *fileName, struct cell *main_cell,
                              struct solution_part *solution, int with_solution) {
      FILE *file = fopen(fileName, "w");
    
      /* Write header */
      fprintf(file,
              "# %4s %8s %8s %8s %8s %8s %8s %8s %8s %8s %8s %8s %8s %8s %13s %13s "
              "%13s %13s %13s %8s %8s\n",
              "ID", "pos_x", "pos_y", "pos_z", "v_x", "v_y", "v_z", "h", "rho",
              "div_v", "S", "u", "P", "c", "a_x", "a_y", "a_z", "h_dt", "v_sig",
              "dS/dt", "du/dt");
    
      fprintf(file, "# Main cell --------------------------------------------\n");
    
      /* Write main cell */
      for (int pid = 0; pid < main_cell->count; pid++) {
        fprintf(file,
                "%6llu %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f "
                "%8.5f "
                "%8.5f %8.5f %13e %13e %13e %13e %13e %8.5f %8.5f\n",
                main_cell->parts[pid].id, main_cell->parts[pid].x[0],
                main_cell->parts[pid].x[1], main_cell->parts[pid].x[2],
                main_cell->parts[pid].v[0], main_cell->parts[pid].v[1],
                main_cell->parts[pid].v[2], main_cell->parts[pid].h,
                hydro_get_comoving_density(&main_cell->parts[pid]),
    #if defined(MINIMAL_SPH) || defined(MINIMAL_MULTI_MAT_SPH) || \
        defined(SHADOWFAX_SPH)
                0.f,
    #else
                main_cell->parts[pid].density.div_v,
    #endif
                hydro_get_comoving_entropy(&main_cell->parts[pid]),
                hydro_get_comoving_internal_energy(&main_cell->parts[pid]),
                hydro_get_comoving_pressure(&main_cell->parts[pid]),
                hydro_get_comoving_soundspeed(&main_cell->parts[pid]),
                main_cell->parts[pid].a_hydro[0], main_cell->parts[pid].a_hydro[1],
                main_cell->parts[pid].a_hydro[2], main_cell->parts[pid].force.h_dt,
    #if defined(GADGET2_SPH)
                main_cell->parts[pid].force.v_sig, main_cell->parts[pid].entropy_dt,
                0.f
    #elif defined(DEFAULT_SPH)
                main_cell->parts[pid].force.v_sig, 0.f,
                main_cell->parts[pid].force.u_dt
    #elif defined(MINIMAL_SPH)
                main_cell->parts[pid].force.v_sig, 0.f, main_cell->parts[pid].u_dt
    #else
                0.f, 0.f, 0.f
    #endif
                );
      }
    
      if (with_solution) {
    
        fprintf(file, "# Solution ---------------------------------------------\n");
    
        for (int pid = 0; pid < main_cell->count; pid++) {
          fprintf(file,
                  "%6llu %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f %8.5f "
                  "%8.5f %8.5f "
                  "%8.5f %8.5f %13f %13f %13f %13f %13f %8.5f %8.5f\n",
                  solution[pid].id, solution[pid].x[0], solution[pid].x[1],
                  solution[pid].x[2], solution[pid].v[0], solution[pid].v[1],
                  solution[pid].v[2], solution[pid].h, solution[pid].rho,
                  solution[pid].div_v, solution[pid].S, solution[pid].u,
                  solution[pid].P, solution[pid].c, solution[pid].a_hydro[0],
                  solution[pid].a_hydro[1], solution[pid].a_hydro[2],
                  solution[pid].h_dt, solution[pid].v_sig, solution[pid].S_dt,
                  solution[pid].u_dt);
        }
      }
    
      fclose(file);
    }
    
    /* Just a forward declaration... */
    void runner_dopair1_branch_density(struct runner *r, struct cell *ci,
                                       struct cell *cj);
    void runner_doself1_density(struct runner *r, struct cell *ci);
    void runner_dopair2_branch_force(struct runner *r, struct cell *ci,
                                     struct cell *cj);
    void runner_doself2_force(struct runner *r, struct cell *ci);
    void runner_doself2_force_vec(struct runner *r, struct cell *ci);
    
    /* And go... */
    int main(int argc, char *argv[]) {
    
    #ifdef HAVE_SETAFFINITY
      engine_pin();
    #endif
    
      size_t runs = 0, particles = 0;
      double h = 1.23485, size = 1., rho = 2.5;
      double perturbation = 0.;
      char outputFileNameExtension[100] = "";
      char outputFileName[200] = "";
      enum velocity_field vel = velocity_zero;
      enum pressure_field press = pressure_const;
    
      /* Initialize CPU frequency, this also starts time. */
      unsigned long long cpufreq = 0;
      clocks_set_cpufreq(cpufreq);
    
    /* Choke on FP-exceptions */
    #ifdef HAVE_FE_ENABLE_EXCEPT
      feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW);
    #endif
    
      /* Get some randomness going */
      srand(0);
    
      char c;
      while ((c = getopt(argc, argv, "m:s:h:n:r:t:d:f:v:p:")) != -1) {
        switch (c) {
          case 'h':
            sscanf(optarg, "%lf", &h);
            break;
          case 's':
            sscanf(optarg, "%lf", &size);
            break;
          case 'n':
            sscanf(optarg, "%zu", &particles);
            break;
          case 'r':
            sscanf(optarg, "%zu", &runs);
            break;
          case 'd':
            sscanf(optarg, "%lf", &perturbation);
            break;
          case 'm':
            sscanf(optarg, "%lf", &rho);
            break;
          case 'f':
            strcpy(outputFileNameExtension, optarg);
            break;
          case 'v':
            sscanf(optarg, "%d", (int *)&vel);
            break;
          case 'p':
            sscanf(optarg, "%d", (int *)&press);
            break;
          case '?':
            error("Unknown option.");
            break;
        }
      }
    
      if (h < 0 || particles == 0 || runs == 0) {
        printf(
            "\nUsage: %s -n PARTICLES_PER_AXIS -r NUMBER_OF_RUNS [OPTIONS...]\n"
            "\nGenerates 125 cells, filled with particles on a Cartesian grid."
            "\nThese are then interacted using runner_dopair1_density() and "
            "runner_doself1_density() followed by runner_dopair2_force() and "
            "runner_doself2_force()"
            "\n\nOptions:"
            "\n-h DISTANCE=1.2348 - Smoothing length in units of <x>"
            "\n-m rho             - Physical density in the cell"
            "\n-s size            - Physical size of the cell"
            "\n-d pert            - Perturbation to apply to the particles [0,1["
            "\n-v type (0,1,2,3)  - Velocity field: (zero, constant, divergent, "
            "rotating)"
            "\n-p type (0,1,2)    - Pressure field: (constant, gradient divergent)"
            "\n-f fileName        - Part of the file name used to save the dumps\n",
            argv[0]);
        exit(1);
      }
    
      /* Help users... */
      message("DOSELF2 function called: %s", DOSELF2_NAME);
      message("DOPAIR2 function called: %s", DOPAIR2_NAME);
      message("Adiabatic index: ga = %f", hydro_gamma);
      message("Hydro implementation: %s", SPH_IMPLEMENTATION);
      message("Smoothing length: h = %f", h * size);
      message("Kernel:               %s", kernel_name);
      message("Neighbour target: N = %f", pow_dimension(h) * kernel_norm);
      message("Density target: rho = %f", rho);
      message("div_v target:   div = %f", vel == 2 ? 3.f : 0.f);
      message("curl_v target: curl = [0., 0., %f]", vel == 3 ? -2.f : 0.f);
      if (press == pressure_const)
        message("P field constant");
      else if (press == pressure_gradient)
        message("P field gradient");
      else
        message("P field divergent");
    
      printf("\n");
    
    #if !defined(HYDRO_DIMENSION_3D)
      message("test125cells only useful in 3D. Change parameters in const.h !");
      return 1;
    #endif
    
      /* Build the infrastructure */
      struct space space;
      space.periodic = 1;
      space.dim[0] = 5.;
      space.dim[1] = 5.;
      space.dim[2] = 5.;
      hydro_space_init(&space.hs, &space);
    
      struct phys_const prog_const;
      prog_const.const_newton_G = 1.f;
    
      struct hydro_props hp;
      hp.eta_neighbours = h;
      hp.h_tolerance = 1e0;
      hp.h_max = FLT_MAX;
      hp.max_smoothing_iterations = 1;
      hp.CFL_condition = 0.1;
    
      struct engine engine;
      bzero(&engine, sizeof(struct engine));
      engine.hydro_properties = &hp;
      engine.physical_constants = &prog_const;
      engine.s = &space;
      engine.time = 0.1f;
      engine.ti_current = 8;
      engine.max_active_bin = num_time_bins;
      engine.nodeID = NODE_ID;
    
      struct cosmology cosmo;
      cosmology_init_no_cosmo(&cosmo);
      engine.cosmology = &cosmo;
    
      struct runner runner;
      runner.e = &engine;
    
      /* Construct some cells */
      struct cell *cells[125];
      struct cell *inner_cells[27];
      struct cell *main_cell;
      int count = 0;
      static long long partId = 0;
      for (int i = 0; i < 5; ++i) {
        for (int j = 0; j < 5; ++j) {
          for (int k = 0; k < 5; ++k) {
    
            /* Position of the cell */
            const double offset[3] = {i * size, j * size, k * size};
    
            /* Construct it */
            cells[i * 25 + j * 5 + k] = make_cell(
                particles, offset, size, h, rho, &partId, perturbation, vel, press);
    
            /* Store the inner cells */
            if (i > 0 && i < 4 && j > 0 && j < 4 && k > 0 && k < 4) {
              inner_cells[count] = cells[i * 25 + j * 5 + k];
              count++;
            }
          }
        }
      }
    
      /* Store the main cell for future use */
      main_cell = cells[62];
    
      /* Construct the real solution */
      struct solution_part *solution =
          malloc(main_cell->count * sizeof(struct solution_part));
      get_solution(main_cell, solution, rho, vel, press, size);
    
      ticks timings[27];
      for (int i = 0; i < 27; i++) timings[i] = 0;
    
      /* Start the test */
      ticks time = 0;
      for (size_t n = 0; n < runs; ++n) {
    
        const ticks tic = getticks();
    
        /* Initialise the particles */
        for (int j = 0; j < 125; ++j) runner_do_drift_part(&runner, cells[j], 0);
    
        /* Reset particles. */
        for (int i = 0; i < 125; ++i) {
          for (int pid = 0; pid < cells[i]->count; ++pid)
            hydro_init_part(&cells[i]->parts[pid], &space.hs);
        }
    
        /* First, sort stuff */
        for (int j = 0; j < 125; ++j)
          runner_do_sort(&runner, cells[j], 0x1FFF, 0, 0);
    
    /* Do the density calculation */
    
    /* Initialise the particle cache. */
    #ifdef WITH_VECTORIZATION
        runner.ci_cache.count = 0;
        cache_init(&runner.ci_cache, 512);
        runner.cj_cache.count = 0;
        cache_init(&runner.cj_cache, 512);
    #endif
    
        /* Run all the pairs (only once !)*/
        for (int i = 0; i < 5; i++) {
          for (int j = 0; j < 5; j++) {
            for (int k = 0; k < 5; k++) {
    
              struct cell *ci = cells[i * 25 + j * 5 + k];
    
              for (int ii = -1; ii < 2; ii++) {
                int iii = i + ii;
                if (iii < 0 || iii >= 5) continue;
                iii = (iii + 5) % 5;
                for (int jj = -1; jj < 2; jj++) {
                  int jjj = j + jj;
                  if (jjj < 0 || jjj >= 5) continue;
                  jjj = (jjj + 5) % 5;
                  for (int kk = -1; kk < 2; kk++) {
                    int kkk = k + kk;
                    if (kkk < 0 || kkk >= 5) continue;
                    kkk = (kkk + 5) % 5;
    
                    struct cell *cj = cells[iii * 25 + jjj * 5 + kkk];
    
                    if (cj > ci) runner_dopair1_branch_density(&runner, ci, cj);
                  }
                }
              }
            }
          }
        }
    
        /* And now the self-interaction for the central cells*/
        for (int j = 0; j < 27; ++j)
          runner_doself1_density(&runner, inner_cells[j]);
    
        /* Ghost to finish everything on the central cells */
        for (int j = 0; j < 27; ++j) runner_do_ghost(&runner, inner_cells[j], 0);
    
    /* Do the force calculation */
    
    #ifdef WITH_VECTORIZATION
        /* Initialise the cache. */
        runner.ci_cache.count = 0;
        runner.cj_cache.count = 0;
        cache_init(&runner.ci_cache, 512);
        cache_init(&runner.cj_cache, 512);
    #endif
    
        int ctr = 0;
        /* Do the pairs (for the central 27 cells) */
        for (int i = 1; i < 4; i++) {
          for (int j = 1; j < 4; j++) {
            for (int k = 1; k < 4; k++) {
    
              struct cell *cj = cells[i * 25 + j * 5 + k];
    
              if (main_cell != cj) {
    
                const ticks sub_tic = getticks();
    
                DOPAIR2(&runner, main_cell, cj);
    
                timings[ctr++] += getticks() - sub_tic;
              }
            }
          }
        }
    
        ticks self_tic = getticks();
    
        /* And now the self-interaction for the main cell */
        DOSELF2(&runner, main_cell);
    
        timings[26] += getticks() - self_tic;
    
        /* Finally, give a gentle kick */
        runner_do_end_force(&runner, main_cell, 0);
        const ticks toc = getticks();
        time += toc - tic;
    
        /* Dump if necessary */
        if (n == 0) {
          sprintf(outputFileName, "swift_dopair_125_%s.dat",
                  outputFileNameExtension);
          dump_particle_fields(outputFileName, main_cell, solution, 0);
        }
    
        for (int i = 0; i < 125; ++i) {
          for (int pid = 0; pid < cells[i]->count; ++pid)
            hydro_init_part(&cells[i]->parts[pid], &space.hs);
        }
      }
    
      /* Output timing */
      ticks corner_time = timings[0] + timings[2] + timings[6] + timings[8] +
                          timings[17] + timings[19] + timings[23] + timings[25];
    
      ticks edge_time = timings[1] + timings[3] + timings[5] + timings[7] +
                        timings[9] + timings[11] + timings[14] + timings[16] +
                        timings[18] + timings[20] + timings[22] + timings[24];
    
      ticks face_time = timings[4] + timings[10] + timings[12] + timings[13] +
                        timings[15] + timings[21];
    
      ticks self_time = timings[26];
    
      message("Corner calculations took       : %15lli ticks.", corner_time / runs);
      message("Edge calculations took         : %15lli ticks.", edge_time / runs);
      message("Face calculations took         : %15lli ticks.", face_time / runs);
      message("Self calculations took         : %15lli ticks.", self_time / runs);
      message("SWIFT calculation took         : %15lli ticks.", time / runs);
    
      for (int j = 0; j < 125; ++j)
        reset_particles(cells[j], &space.hs, vel, press, size, rho);
    
      /* NOW BRUTE-FORCE CALCULATION */
    
      const ticks tic = getticks();
    
      /* Kick the central cell */
      // runner_do_kick1(&runner, main_cell, 0);
    
      /* And drift it */
      // runner_do_drift_particles(&runner, main_cell, 0);
    
      /* Initialise the particles */
      // for (int j = 0; j < 125; ++j) runner_do_drift_particles(&runner, cells[j],
      // 0);
    
      /* Do the density calculation */
    
      /* Run all the pairs (only once !)*/
      for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 5; j++) {
          for (int k = 0; k < 5; k++) {
    
            struct cell *ci = cells[i * 25 + j * 5 + k];
    
            for (int ii = -1; ii < 2; ii++) {
              int iii = i + ii;
              if (iii < 0 || iii >= 5) continue;
              iii = (iii + 5) % 5;
              for (int jj = -1; jj < 2; jj++) {
                int jjj = j + jj;
                if (jjj < 0 || jjj >= 5) continue;
                jjj = (jjj + 5) % 5;
                for (int kk = -1; kk < 2; kk++) {
                  int kkk = k + kk;
                  if (kkk < 0 || kkk >= 5) continue;
                  kkk = (kkk + 5) % 5;
    
                  struct cell *cj = cells[iii * 25 + jjj * 5 + kkk];
    
                  if (cj > ci) pairs_all_density(&runner, ci, cj);
                }
              }
            }
          }
        }
      }
    
      /* And now the self-interaction for the central cells*/
      for (int j = 0; j < 27; ++j) self_all_density(&runner, inner_cells[j]);
    
      /* Ghost to finish everything on the central cells */
      for (int j = 0; j < 27; ++j) runner_do_ghost(&runner, inner_cells[j], 0);
    
      /* Do the force calculation */
    
      /* Do the pairs (for the central 27 cells) */
      for (int i = 1; i < 4; i++) {
        for (int j = 1; j < 4; j++) {
          for (int k = 1; k < 4; k++) {
    
            struct cell *cj = cells[i * 25 + j * 5 + k];
    
            if (main_cell != cj) pairs_all_force(&runner, main_cell, cj);
          }
        }
      }
    
      /* And now the self-interaction for the main cell */
      self_all_force(&runner, main_cell);
    
      /* Finally, give a gentle kick */
      runner_do_end_force(&runner, main_cell, 0);
      // runner_do_kick2(&runner, main_cell, 0);
    
      const ticks toc = getticks();
    
      /* Output timing */
      message("Brute force calculation took : %15lli ticks.", toc - tic);
    
      sprintf(outputFileName, "brute_force_125_%s.dat", outputFileNameExtension);
      dump_particle_fields(outputFileName, main_cell, solution, 0);
    
      /* Clean things to make the sanitizer happy ... */
      for (int i = 0; i < 125; ++i) clean_up(cells[i]);
      free(solution);
    
      return 0;
    }