Impose an ordering on the BH that are merging in a chain.

examples/SubgridTests/BlackHoleSwallowing/makeIC.py

@@ -21,8 +21,8 @@ import h5py
 from numpy import *
 
 # Some constants
-solar_mass_cgs = 1.988480e33 
-kpc_in_cm = 3.085678e21
+solar_mass_cgs = 1.988410e33 
+kpc_in_cm = 3.08567758149e21
 mp_cgs = 1.67e-24
 boltzmann_k_cgs = 1.38e-16
 
@@ -34,8 +34,8 @@ P_cgs = rho_cgs*u0_cgs*(gamma - 1.)          	# Background pressure
 fileName = "bh_swallowing.hdf5" 
 
 # Units
-unit_l_cgs = 3.085678e24  # kpc
-unit_m_cgs = 1.988480e43  # 10^10 Msun
+unit_l_cgs = 3.08567758149e24  # kpc
+unit_m_cgs = 1.988410e43       # 10^10 Msun
 unit_v_cgs = 1e5          # km / s
 unit_A_cgs = 1.
 unit_T_cgs = 1.

examples/SubgridTests/BlackHoleSwallowing/swallowing.yml

 # Define the system of units to use internally. 
 InternalUnitSystem:
-  UnitMass_in_cgs:     1.98848e43    # 10^10 M_sun in grams
-  UnitLength_in_cgs:   3.08567758e24 # Mpc in centimeters
+  UnitMass_in_cgs:     1.98841e43       # 10^10 M_sun in grams
+  UnitLength_in_cgs:   3.08567758149e24 # Mpc in centimeters
   UnitVelocity_in_cgs: 1e5           # km/s in centimeters per second
   UnitCurrent_in_cgs:  1.            # Amperes
   UnitTemp_in_cgs:     1.            # Kelvin
@@ -34,6 +34,17 @@ Statistics:
   time_first:          0.
   delta_time:          1.e-5  # non cosmology time between statistics output
 
+# Parameters for the self-gravity scheme
+Gravity:
+  eta:                    0.025     # Constant dimensionless multiplier for time integration.
+  theta:                  0.7       # Opening angle (Multipole acceptance criterion)
+  mesh_side_length:       128
+  comoving_DM_softening:         0.003320 # Comoving softening for DM (3.32 ckpc)
+  max_physical_DM_softening:     0.001300 # Physical softening for DM (1.30 pkpc)
+  comoving_baryon_softening:     0.001790 # Comoving softening for baryons (1.79 ckpc)
+  max_physical_baryon_softening: 0.000700 # Physical softening for baryons (0.70 pkpc)
+  dithering:             0
+  
 # Parameters for the hydrodynamics scheme
 SPH:
   resolution_eta:        1.2348   # Target smoothing length in units of the mean inter-particle separation 
@@ -47,7 +58,6 @@ InitialConditions:
   
 Scheduler:
   max_top_level_cells: 8
-  tasks_per_cell:      500			
 
 # Parameters for the EAGLE "equation of state"
 EAGLEEntropyFloor:

src/runner_black_holes.c

@@ -347,23 +347,20 @@ void runner_do_bh_swallow(struct runner *r, struct cell *c, int timer) {
 
           if (bp->id == BH_id) {
 
-            /* Lock the space as we are going to work directly on the bpart list
-             */
-            lock_lock(&s->lock);
+            /* Is the swallowing BH itself flagged for swallowing by
+               another BH? */
+            if (black_holes_get_bpart_swallow_id(&bp->merger_data) != -1) {
 
-            /* If bpart is inhibited, it cannot do any swallowing */
-            if (bpart_is_inhibited(bp, e)) {
-              message("BH %lld inhibited -- DOES NOT swallow BH %lld", bp->id,
-                      cell_bp->id);
-
-              /* Pretend it was found */
+              /* Pretend it was found and abort */
+              black_holes_mark_bpart_as_not_swallowed(&cell_bp->merger_data);
               found = 1;
-
-              if (lock_unlock(&s->lock) != 0)
-                error("Failed to unlock the space.");
               break;
             }
 
+            /* Lock the space as we are going to work directly on the
+             * space's bpart list */
+            lock_lock(&s->lock);
+
             /* Swallow the BH particle (i.e. update the swallowing BH
              * properties with the properties of cell_bp) */
             black_holes_swallow_bpart(bp, cell_bp, e->cosmology, e->time,
@@ -410,6 +407,16 @@ void runner_do_bh_swallow(struct runner *r, struct cell *c, int timer) {
 
             if (bp->id == BH_id) {
 
+              /* Is the swallowing BH itself flagged for swallowing by
+                 another BH? */
+              if (black_holes_get_bpart_swallow_id(&bp->merger_data) != -1) {
+
+                /* Pretend it was found and abort */
+                black_holes_mark_bpart_as_not_swallowed(&cell_bp->merger_data);
+                found = 1;
+                break;
+              }
+
               message("BH %lld removing BH particle %lld (foreign BH case)",
                       bp->id, cell_bp->id);