Merge branch 'gravity_fixes' into 'master'

Correct wrapping of multipoles in FFT task

See merge request !433

examples/EAGLE_12/eagle_12.yml

@@ -27,7 +27,7 @@ Statistics:
 Gravity:
   eta:                   0.025    # Constant dimensionless multiplier for time integration.
   epsilon:               0.001    # Softening length (in internal units).
-  theta:                 0.7      # Opening angle (Multipole acceptance criterion)
+  theta:                 0.85     # Opening angle (Multipole acceptance criterion)
   
 # Parameters for the hydrodynamics scheme
 SPH:

examples/EAGLE_25/eagle_25.yml

@@ -13,6 +13,9 @@ TimeIntegration:
   dt_min:     1e-10 # The minimal time-step size of the simulation (in internal units).
   dt_max:     1e-4  # The maximal time-step size of the simulation (in internal units).
 
+Scheduler:
+  max_top_level_cells:    20
+
 # Parameters governing the snapshots
 Snapshots:
   basename:            eagle # Common part of the name of output files
@@ -26,8 +29,8 @@ Statistics:
 # Parameters for the self-gravity scheme
 Gravity:
   eta:                   0.025    # Constant dimensionless multiplier for time integration. 
-  epsilon:               0.0001   # Softening length (in internal units).
-  theta:                 0.7      # Opening angle (Multipole acceptance criterion)
+  epsilon:               0.001    # Softening length (in internal units).
+  theta:                 0.85     # Opening angle (Multipole acceptance criterion)
   
 # Parameters for the hydrodynamics scheme
 SPH:

examples/EAGLE_50/eagle_50.yml

@@ -26,8 +26,8 @@ Statistics:
 # Parameters for the self-gravity scheme
 Gravity:
   eta:                   0.025    # Constant dimensionless multiplier for time integration.
-  epsilon:               0.0001   # Softening length (in internal units).
-  theta:                 0.7      # Opening angle (Multipole acceptance criterion)
+  epsilon:               0.001    # Softening length (in internal units).
+  theta:                 0.85     # Opening angle (Multipole acceptance criterion)
 
 # Parameters for the hydrodynamics scheme
 SPH:

examples/EAGLE_6/eagle_6.yml

@@ -6,6 +6,10 @@ InternalUnitSystem:
   UnitCurrent_in_cgs:  1             # Amperes
   UnitTemp_in_cgs:     1             # Kelvin
 
+Scheduler:
+  max_top_level_cells: 8
+  tasks_per_cell: 50
+  
 # Parameters governing the time integration
 TimeIntegration:
   time_begin: 0.    # The starting time of the simulation (in internal units).
@@ -26,8 +30,8 @@ Statistics:
 # Parameters for the self-gravity scheme
 Gravity:
   eta:                   0.025    # Constant dimensionless multiplier for time integration.
-  theta:                 0.85     # Opening angle (Multipole acceptance criterion)
   epsilon:               0.001    # Softening length (in internal units).
+  theta:                 0.85     # Opening angle (Multipole acceptance criterion)
   
 # Parameters for the hydrodynamics scheme
 SPH:

examples/UniformDMBox/uniformBox.yml

@@ -9,9 +9,9 @@ InternalUnitSystem:
 # Parameters governing the time integration
 TimeIntegration:
   time_begin: 0.    # The starting time of the simulation (in internal units).
-  time_end:   1.    # The end time of the simulation (in internal units).
+  time_end:   100.    # The end time of the simulation (in internal units).
   dt_min:     1e-6  # The minimal time-step size of the simulation (in internal units).
-  dt_max:     1e-3  # The maximal time-step size of the simulation (in internal units).
+  dt_max:     1.  # The maximal time-step size of the simulation (in internal units).
 
 Scheduler:
   max_top_level_cells: 8
@@ -21,18 +21,18 @@ Scheduler:
 Snapshots:
   basename:            uniformDMBox # Common part of the name of output files
   time_first:          0.           # Time of the first output (in internal units)
-  delta_time:          0.01         # Time difference between consecutive outputs (in internal units)
+  delta_time:          10.         # Time difference between consecutive outputs (in internal units)
 
 # Parameters for the self-gravity scheme
 Gravity:
   eta:                   0.025    # Constant dimensionless multiplier for time integration. 
-  theta:                 0.7      # Opening angle (Multipole acceptance criterion)
-  epsilon:               0.00001  # Softening length (in internal units).
+  theta:                 0.8      # Opening angle (Multipole acceptance criterion)
+  epsilon:               0.01     # Softening length (in internal units).
  
 # Parameters governing the conserved quantities statistics
 Statistics:
-  delta_time:          1e-2 # Time between statistics output
+  delta_time:          5. # Time between statistics output
 
 # Parameters related to the initial conditions
 InitialConditions:
-  file_name:  ./uniformDMBox_50.hdf5     # The file to read
+  file_name:  ./uniformDMBox_16.hdf5     # The file to read

examples/analyse_tasks.py

@@ -52,11 +52,10 @@ infile = args.input
 
 #  Tasks and subtypes. Indexed as in tasks.h.
 TASKTYPES = ["none", "sort", "self", "pair", "sub_self", "sub_pair",
-             "init_grav", "ghost", "extra_ghost", "drift_part",
-             "drift_gpart", "kick1", "kick2", "timestep", "send", "recv",
-             "grav_top_level", "grav_long_range", "grav_mm", "grav_down",
-             "cooling", "sourceterms", "count"]
-
+             "init_grav", "ghost_in", "ghost", "ghost_out", "extra_ghost", "drift_part", "drift_gpart",
+             "kick1", "kick2", "timestep", "send", "recv", "grav_top_level",
+             "grav_long_range", "grav_ghost_in", "grav_ghost_out", "grav_mm", "grav_down", "cooling",
+             "sourceterms", "count"]
 SUBTYPES = ["none", "density", "gradient", "force", "grav", "external_grav",
             "tend", "xv", "rho", "gpart", "multipole", "spart", "count"]
 

examples/check_ngbs.py

@@ -18,8 +18,6 @@ inputFile2 = ""
 # Check list of density neighbours and check that they are correct.
 def check_density_neighbours(pids, ngb_ids_naive, ngb_ids_sort, mask, pos, h, num_invalid, acc):
 
-    error_val = False
-
     for k in range(0,num_invalid):
 
         # Filter neighbour lists for valid particle ids
@@ -28,7 +26,21 @@ def check_density_neighbours(pids, ngb_ids_naive, ngb_ids_sort, mask, pos, h, nu
 
         # Check neighbour lists for differences
         id_list = set(filter_neigh_naive).symmetric_difference(set(filter_neigh_sort))
+       
+        # Check for duplicate IDs
+        duplicate_check_naive = len(filter_neigh_naive) != len(set(filter_neigh_naive))
+        duplicate_check_sort = len(filter_neigh_sort) != len(set(filter_neigh_sort))
+
+        if duplicate_check_naive:
+            print "Duplicate neighbour ID found in: ", inputFile1
+            print filter_neigh_naive
+            return True
         
+        if duplicate_check_sort:
+            print "Duplicate neighbour ID found in: ", inputFile2
+            print filter_neigh_sort
+            return True
+
         pid = pids[mask][k]
 
         # Loop over discrepancies and check if they are actually neighbours
@@ -53,9 +65,9 @@ def check_density_neighbours(pids, ngb_ids_naive, ngb_ids_sort, mask, pos, h, nu
             if diff < acc * hig2:
                 print "Missing interaction due to precision issue will be ignored."
             else:
-                error_val = True
+                return True
 
-    return error_val
+    return False
 
 # Check list of force neighbours and check that they are correct.
 def check_force_neighbours(pids, ngb_ids_naive, ngb_ids_sort, mask, pos, h, num_invalid, acc):

examples/plot_tasks.py

@@ -110,9 +110,9 @@ pl.rcParams.update(PLOT_PARAMS)
 
 #  Tasks and subtypes. Indexed as in tasks.h.
 TASKTYPES = ["none", "sort", "self", "pair", "sub_self", "sub_pair",
-             "init_grav", "ghost", "extra_ghost", "drift_part", "drift_gpart",
+             "init_grav", "ghost_in", "ghost", "ghost_out", "extra_ghost", "drift_part", "drift_gpart",
              "kick1", "kick2", "timestep", "send", "recv", "grav_top_level",
-             "grav_long_range", "grav_mm", "grav_down", "cooling",
+             "grav_long_range", "grav_ghost_in", "grav_ghost_out", "grav_mm", "grav_down", "cooling",
              "sourceterms", "count"]
 
 SUBTYPES = ["none", "density", "gradient", "force", "grav", "external_grav",
@@ -123,7 +123,7 @@ FULLTYPES = ["self/force", "self/density", "self/grav", "sub_self/force",
              "sub_self/density", "pair/force", "pair/density", "pair/grav",
              "sub_pair/force",
              "sub_pair/density", "recv/xv", "send/xv", "recv/rho", "send/rho",
-             "recv/tend", "send/tend"]
+             "recv/tend", "send/tend", "recv/gpart", "send/gpart"]
 
 #  A number of colours for the various types. Recycled when there are
 #  more task types than colours...

src/active.h

@@ -82,19 +82,19 @@ __attribute__((always_inline)) INLINE static int cell_are_gpart_drifted(
  * @param e The #engine containing information about the current time.
  * @return 1 if the #cell contains at least an active particle, 0 otherwise.
  */
-__attribute__((always_inline)) INLINE static int cell_is_active(
+__attribute__((always_inline)) INLINE static int cell_is_active_hydro(
     const struct cell *c, const struct engine *e) {
 
 #ifdef SWIFT_DEBUG_CHECKS
-  if (c->ti_end_min < e->ti_current)
+  if (c->ti_hydro_end_min < e->ti_current)
     error(
         "cell in an impossible time-zone! c->ti_end_min=%lld (t=%e) and "
         "e->ti_current=%lld (t=%e)",
-        c->ti_end_min, c->ti_end_min * e->timeBase, e->ti_current,
+        c->ti_hydro_end_min, c->ti_hydro_end_min * e->timeBase, e->ti_current,
         e->ti_current * e->timeBase);
 #endif
 
-  return (c->ti_end_min == e->ti_current);
+  return (c->ti_hydro_end_min == e->ti_current);
 }
 
 /**
@@ -104,18 +104,61 @@ __attribute__((always_inline)) INLINE static int cell_is_active(
  * @param e The #engine containing information about the current time.
  * @return 1 if all particles in a #cell are active, 0 otherwise.
  */
-__attribute__((always_inline)) INLINE static int cell_is_all_active(
+__attribute__((always_inline)) INLINE static int cell_is_all_active_hydro(
     const struct cell *c, const struct engine *e) {
 
 #ifdef SWIFT_DEBUG_CHECKS
-  if (c->ti_end_max < e->ti_current)
+  if (c->ti_hydro_end_max < e->ti_current)
     error(
         "cell in an impossible time-zone! c->ti_end_max=%lld "
         "e->ti_current=%lld",
-        c->ti_end_max, e->ti_current);
+        c->ti_hydro_end_max, e->ti_current);
 #endif
 
-  return (c->ti_end_max == e->ti_current);
+  return (c->ti_hydro_end_max == e->ti_current);
+}
+
+/**
+ * @brief Does a cell contain any g-particle finishing their time-step now ?
+ *
+ * @param c The #cell.
+ * @param e The #engine containing information about the current time.
+ * @return 1 if the #cell contains at least an active particle, 0 otherwise.
+ */
+__attribute__((always_inline)) INLINE static int cell_is_active_gravity(
+    const struct cell *c, const struct engine *e) {
+
+#ifdef SWIFT_DEBUG_CHECKS
+  if (c->ti_gravity_end_min < e->ti_current)
+    error(
+        "cell in an impossible time-zone! c->ti_end_min=%lld (t=%e) and "
+        "e->ti_current=%lld (t=%e)",
+        c->ti_gravity_end_min, c->ti_gravity_end_min * e->timeBase,
+        e->ti_current, e->ti_current * e->timeBase);
+#endif
+
+  return (c->ti_gravity_end_min == e->ti_current);
+}
+
+/**
+ * @brief Are *all* g-particles in a cell finishing their time-step now ?
+ *
+ * @param c The #cell.
+ * @param e The #engine containing information about the current time.
+ * @return 1 if all particles in a #cell are active, 0 otherwise.
+ */
+__attribute__((always_inline)) INLINE static int cell_is_all_active_gravity(
+    const struct cell *c, const struct engine *e) {
+
+#ifdef SWIFT_DEBUG_CHECKS
+  if (c->ti_gravity_end_max < e->ti_current)
+    error(
+        "cell in an impossible time-zone! c->ti_end_max=%lld "
+        "e->ti_current=%lld",
+        c->ti_gravity_end_max, e->ti_current);
+#endif
+
+  return (c->ti_gravity_end_max == e->ti_current);
 }
 
 /**
@@ -215,19 +258,41 @@ __attribute__((always_inline)) INLINE static int spart_is_active(
  * @param e The #engine containing information about the current time.
  * @return 1 if the #cell contains at least an active particle, 0 otherwise.
  */
-__attribute__((always_inline)) INLINE static int cell_is_starting(
+__attribute__((always_inline)) INLINE static int cell_is_starting_hydro(
     const struct cell *c, const struct engine *e) {
 
 #ifdef SWIFT_DEBUG_CHECKS
-  if (c->ti_beg_max > e->ti_current)
+  if (c->ti_hydro_beg_max > e->ti_current)
     error(
         "cell in an impossible time-zone! c->ti_beg_max=%lld (t=%e) and "
         "e->ti_current=%lld (t=%e)",
-        c->ti_beg_max, c->ti_beg_max * e->timeBase, e->ti_current,
+        c->ti_hydro_beg_max, c->ti_hydro_beg_max * e->timeBase, e->ti_current,
         e->ti_current * e->timeBase);
 #endif
 
-  return (c->ti_beg_max == e->ti_current);
+  return (c->ti_hydro_beg_max == e->ti_current);
+}
+
+/**
+ * @brief Does a cell contain any g-particle starting their time-step now ?
+ *
+ * @param c The #cell.
+ * @param e The #engine containing information about the current time.
+ * @return 1 if the #cell contains at least an active particle, 0 otherwise.
+ */
+__attribute__((always_inline)) INLINE static int cell_is_starting_gravity(
+    const struct cell *c, const struct engine *e) {
+
+#ifdef SWIFT_DEBUG_CHECKS
+  if (c->ti_gravity_beg_max > e->ti_current)
+    error(
+        "cell in an impossible time-zone! c->ti_beg_max=%lld (t=%e) and "
+        "e->ti_current=%lld (t=%e)",
+        c->ti_gravity_beg_max, c->ti_gravity_beg_max * e->timeBase,
+        e->ti_current, e->ti_current * e->timeBase);
+#endif
+
+  return (c->ti_gravity_beg_max == e->ti_current);
 }
 
 /**

src/cell.h

@@ -80,14 +80,23 @@ struct pcell {
   /*! Maximal smoothing length. */
   double h_max;
 
-  /*! Minimal integer end-of-timestep in this cell */
-  integertime_t ti_end_min;
+  /*! Minimal integer end-of-timestep in this cell for hydro tasks */
+  integertime_t ti_hydro_end_min;
 
-  /*! Maximal integer end-of-timestep in this cell */
-  integertime_t ti_end_max;
+  /*! Maximal integer end-of-timestep in this cell for hydro tasks */
+  integertime_t ti_hydro_end_max;
 
-  /*! Maximal integer beginning-of-timestep in this cell */
-  integertime_t ti_beg_max;
+  /*! Maximal integer beginning-of-timestep in this cell for hydro tasks */
+  integertime_t ti_hydro_beg_max;
+
+  /*! Minimal integer end-of-timestep in this cell for gravity tasks */
+  integertime_t ti_gravity_end_min;
+
+  /*! Maximal integer end-of-timestep in this cell for gravity tasks */
+  integertime_t ti_gravity_end_max;
+
+  /*! Maximal integer beginning-of-timestep in this cell for gravity tasks */
+  integertime_t ti_gravity_beg_max;
 
   /*! Integer time of the last drift of the #part in this cell */
   integertime_t ti_old_part;
@@ -95,6 +104,9 @@ struct pcell {
   /*! Integer time of the last drift of the #gpart in this cell */
   integertime_t ti_old_gpart;
 
+  /*! Integer time of the last drift of the #multipole in this cell */
+  integertime_t ti_old_multipole;
+
   /*! Number of #part in this cell. */
   int count;
 
@@ -110,6 +122,11 @@ struct pcell {
   /*! Relative indices of the cell's progeny. */
   int progeny[8];
 
+#ifdef SWIFT_DEBUG_CHECKS
+  /* Cell ID (for debugging) */
+  int cellID;
+#endif
+
 } SWIFT_STRUCT_ALIGN;
 
 /**
@@ -117,8 +134,17 @@ struct pcell {
  */
 struct pcell_step {
 
-  /*! Minimal integer end-of-timestep in this cell */
-  integertime_t ti_end_min;
+  /*! Minimal integer end-of-timestep in this cell (hydro) */
+  integertime_t ti_hydro_end_min;
+
+  /*! Minimal integer end-of-timestep in this cell (hydro) */
+  integertime_t ti_hydro_end_max;
+
+  /*! Minimal integer end-of-timestep in this cell (gravity) */
+  integertime_t ti_gravity_end_min;
+
+  /*! Minimal integer end-of-timestep in this cell (gravity) */
+  integertime_t ti_gravity_end_max;
 
   /*! Maximal distance any #part has travelled since last rebuild */
   float dx_max_part;
@@ -170,11 +196,16 @@ struct cell {
   /*! Parent cell. */
   struct cell *parent;
 
-  /*! Super cell, i.e. the highest-level parent cell that has pair/self tasks */
+  /*! Super cell, i.e. the highest-level parent cell with *any* task */
   struct cell *super;
 
-  /*! The task computing this cell's sorts. */
-  struct task *sorts;
+  /*! Super cell, i.e. the highest-level parent cell that has a hydro pair/self
+   * tasks */
+  struct cell *super_hydro;
+
+  /*! Super cell, i.e. the highest-level parent cell that has a grav pair/self
+   * tasks */
+  struct cell *super_gravity;
 
   /*! Linked list of the tasks computing this cell's hydro density. */
   struct link *density;
@@ -188,6 +219,9 @@ struct cell {
   /*! Linked list of the tasks computing this cell's gravity forces. */
   struct link *grav;
 
+  /*! The task computing this cell's sorts. */
+  struct task *sorts;
+
   /*! The multipole initialistation task */
   struct task *init_grav;
 
@@ -219,7 +253,7 @@ struct cell {
   struct task *timestep;
 
   /*! Task linking the FFT mesh to the rest of gravity tasks */
-  struct task *grav_ghost[2];
+  struct task *grav_ghost_in, *grav_ghost_out;
 
   /*! Task computing long range non-periodic gravity interactions */
   struct task *grav_long_range;
@@ -235,27 +269,33 @@ struct cell {
 
 #ifdef WITH_MPI
 
-  /* Task receiving data (positions). */
+  /* Task receiving hydro data (positions). */
   struct task *recv_xv;
 
-  /* Task receiving data (density). */
+  /* Task receiving hydro data (density). */
   struct task *recv_rho;
 
-  /* Task receiving data (gradient). */
+  /* Task receiving hydro data (gradient). */
   struct task *recv_gradient;
 
+  /* Task receiving gpart data. */
+  struct task *recv_grav;
+
   /* Task receiving data (time-step). */
   struct task *recv_ti;
 
-  /* Linked list for sending data (positions). */
+  /* Linked list for sending hydro data (positions). */
   struct link *send_xv;
 
-  /* Linked list for sending data (density). */
+  /* Linked list for sending hydro data (density). */
   struct link *send_rho;
 
-  /* Linked list for sending data (gradient). */
+  /* Linked list for sending hydro data (gradient). */
   struct link *send_gradient;
 
+  /* Linked list for sending gpart data. */
+  struct link *send_grav;
+
   /* Linked list for sending data (time-step). */
   struct link *send_ti;
 
@@ -273,14 +313,24 @@ struct cell {
 
 #endif
 
-  /*! Minimum end of (integer) time step in this cell. */
-  integertime_t ti_end_min;
+  /*! Minimum end of (integer) time step in this cell for hydro tasks. */
+  integertime_t ti_hydro_end_min;
+
+  /*! Maximum end of (integer) time step in this cell for hydro tasks. */
+  integertime_t ti_hydro_end_max;
+
+  /*! Maximum beginning of (integer) time step in this cell for hydro tasks. */
+  integertime_t ti_hydro_beg_max;
 
-  /*! Maximum end of (integer) time step in this cell. */
-  integertime_t ti_end_max;
+  /*! Minimum end of (integer) time step in this cell for gravity tasks. */
+  integertime_t ti_gravity_end_min;
 
-  /*! Maximum beginning of (integer) time step in this cell. */
-  integertime_t ti_beg_max;
+  /*! Maximum end of (integer) time step in this cell for gravity tasks. */
+  integertime_t ti_gravity_end_max;
+
+  /*! Maximum beginning of (integer) time step in this cell for gravity tasks.
+   */
+  integertime_t ti_gravity_beg_max;
 
   /*! Last (integer) time the cell's part were drifted forward in time. */
   integertime_t ti_old_part;
@@ -397,6 +447,9 @@ struct cell {
   char do_sub_sort;
 
 #ifdef SWIFT_DEBUG_CHECKS
+  /* Cell ID (for debugging) */
+  int cellID;
+
   /*! Last (integer) time the cell's sort arrays were updated. */
   integertime_t ti_sort;
 
@@ -430,6 +483,8 @@ int cell_pack(struct cell *c, struct pcell *pc);
 int cell_unpack(struct pcell *pc, struct cell *c, struct space *s);
 int cell_pack_end_step(struct cell *c, struct pcell_step *pcell);
 int cell_unpack_end_step(struct cell *c, struct pcell_step *pcell);
+int cell_pack_multipoles(struct cell *c, struct gravity_tensors *m);
+int cell_unpack_multipoles(struct cell *c, struct gravity_tensors *m);
 int cell_getsize(struct cell *c);
 int cell_link_parts(struct cell *c, struct part *parts);
 int cell_link_gparts(struct cell *c, struct gpart *gparts);
@@ -443,7 +498,8 @@ void cell_check_part_drift_point(struct cell *c, void *data);
 void cell_check_gpart_drift_point(struct cell *c, void *data);
 void cell_check_multipole_drift_point(struct cell *c, void *data);
 void cell_reset_task_counters(struct cell *c);
-int cell_unskip_tasks(struct cell *c, struct scheduler *s);
+int cell_unskip_hydro_tasks(struct cell *c, struct scheduler *s);
+int cell_unskip_gravity_tasks(struct cell *c, struct scheduler *s);
 void cell_set_super(struct cell *c, struct cell *super);
 void cell_drift_part(struct cell *c, const struct engine *e, int force);
 void cell_drift_gpart(struct cell *c, const struct engine *e, int force);
@@ -451,8 +507,8 @@ void cell_drift_multipole(struct cell *c, const struct engine *e);
 void cell_drift_all_multipoles(struct cell *c, const struct engine *e);
 void cell_check_timesteps(struct cell *c);
 void cell_store_pre_drift_values(struct cell *c);
-void cell_activate_subcell_tasks(struct cell *ci, struct cell *cj,
-                                 struct scheduler *s);
+void cell_activate_subcell_hydro_tasks(struct cell *ci, struct cell *cj,
+                                       struct scheduler *s);
 void cell_activate_subcell_grav_tasks(struct cell *ci, struct cell *cj,
                                       struct scheduler *s);
 void cell_activate_subcell_external_grav_tasks(struct cell *ci,
@@ -492,12 +548,8 @@ __attribute__((always_inline)) INLINE static int cell_can_recurse_in_pair_task(
 __attribute__((always_inline)) INLINE static int cell_can_recurse_in_self_task(
     const struct cell *c) {
 
-  /* Is the cell split ? */
-  /* Note: No need for more checks here as all the sub-pairs and sub-self */
-  /* operations will be executed. So no need for the particle to be at exactly
-   */
-  /* the right place. */
-  return c->split;
+  /* Is the cell split and not smaller than the smoothing length? */
+  return c->split && (kernel_gamma * c->h_max_old < 0.5f * c->dmin);
 }
 
 /**

src/collectgroup.c

@@ -37,7 +37,8 @@
 /* Local collections for MPI reduces. */
 struct mpicollectgroup1 {
   size_t updates, g_updates, s_updates;
-  integertime_t ti_end_min;
+  integertime_t ti_hydro_end_min;
+  integertime_t ti_gravity_end_min;
   int forcerebuild;
 };
 
@@ -75,9 +76,15 @@ void collectgroup_init() {
  * @param e The #engine
  */
 void collectgroup1_apply(struct collectgroup1 *grp1, struct engine *e) {
-  e->ti_end_min = grp1->ti_end_min;
-  e->ti_end_max = grp1->ti_end_max;
-  e->ti_beg_max = grp1->ti_beg_max;
+  e->ti_hydro_end_min = grp1->ti_hydro_end_min;
+  e->ti_hydro_end_max = grp1->ti_hydro_end_max;
+  e->ti_hydro_beg_max = grp1->ti_hydro_beg_max;
+  e->ti_gravity_end_min = grp1->ti_gravity_end_min;
+  e->ti_gravity_end_max = grp1->ti_gravity_end_max;
+  e->ti_gravity_beg_max = grp1->ti_gravity_beg_max;
+  e->ti_end_min = min(e->ti_hydro_end_min, e->ti_gravity_end_min);
+  e->ti_end_max = max(e->ti_hydro_end_max, e->ti_gravity_end_max);
+  e->ti_beg_max = max(e->ti_hydro_beg_max, e->ti_gravity_beg_max);
   e->updates = grp1->updates;
   e->g_updates = grp1->g_updates;
   e->s_updates = grp1->s_updates;
@@ -92,21 +99,37 @@ void collectgroup1_apply(struct collectgroup1 *grp1, struct engine *e) {
  * @param g_updates the number of updated gravity particles on this node this
  * step.
  * @param s_updates the number of updated star particles on this node this step.
- * @param ti_end_min the minimum end time for next time step after this step.
- * @param ti_end_max the maximum end time for next time step after this step.
- * @param ti_beg_max the maximum begin time for next time step after this step.
+ * @param ti_hydro_end_min the minimum end time for next hydro time step after
+ * this step.
+ * @param ti_hydro_end_max the maximum end time for next hydro time step after
+ * this step.
+ * @param ti_hydro_beg_max the maximum begin time for next hydro time step after
+ * this step.
+ * @param ti_gravity_end_min the minimum end time for next gravity time step
+ * after this step.
+ * @param ti_gravity_end_max the maximum end time for next gravity time step
+ * after this step.
+ * @param ti_gravity_beg_max the maximum begin time for next gravity time step
+ * after this step.
  * @param forcerebuild whether a rebuild is required after this step.
  */
 void collectgroup1_init(struct collectgroup1 *grp1, size_t updates,
                         size_t g_updates, size_t s_updates,
-                        integertime_t ti_end_min, integertime_t ti_end_max,
-                        integertime_t ti_beg_max, int forcerebuild) {
+                        integertime_t ti_hydro_end_min,
+                        integertime_t ti_hydro_end_max,
+                        integertime_t ti_hydro_beg_max,
+                        integertime_t ti_gravity_end_min,
+                        integertime_t ti_gravity_end_max,
+                        integertime_t ti_gravity_beg_max, int forcerebuild) {
   grp1->updates = updates;
   grp1->g_updates = g_updates;
   grp1->s_updates = s_updates;
-  grp1->ti_end_min = ti_end_min;
-  grp1->ti_end_max = ti_end_max;
-  grp1->ti_beg_max = ti_beg_max;
+  grp1->ti_hydro_end_min = ti_hydro_end_min;
+  grp1->ti_hydro_end_max = ti_hydro_end_max;
+  grp1->ti_hydro_beg_max = ti_hydro_beg_max;
+  grp1->ti_gravity_end_min = ti_gravity_end_min;
+  grp1->ti_gravity_end_max = ti_gravity_end_max;
+  grp1->ti_gravity_beg_max = ti_gravity_beg_max;
   grp1->forcerebuild = forcerebuild;
 }
 
@@ -127,7 +150,8 @@ void collectgroup1_reduce(struct collectgroup1 *grp1) {
   mpigrp11.updates = grp1->updates;
   mpigrp11.g_updates = grp1->g_updates;
   mpigrp11.s_updates = grp1->s_updates;
-  mpigrp11.ti_end_min = grp1->ti_end_min;
+  mpigrp11.ti_hydro_end_min =