From ef7b5f19c136c83d4c1d9ac83e3a8d1be58113d4 Mon Sep 17 00:00:00 2001
From: Matthieu Schaller <schaller@strw.leidenuniv.nl>
Date: Thu, 4 Jul 2019 18:19:57 +0200
Subject: [PATCH] Merge onto the most massive of the two BHs.
---
src/black_holes/EAGLE/black_holes_iact.h | 17 +++++++++++------
src/black_holes/EAGLE/black_holes_struct.h | 5 +++++
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/src/black_holes/EAGLE/black_holes_iact.h b/src/black_holes/EAGLE/black_holes_iact.h
index 0bfe2a51e8..bd3d8f0ce2 100644
--- a/src/black_holes/EAGLE/black_holes_iact.h
+++ b/src/black_holes/EAGLE/black_holes_iact.h
@@ -219,11 +219,12 @@ runner_iact_nonsym_bh_bh_swallow(const float r2, const float *dx,
const float G = 43.; // MATTHIEU: Fix this!!!
- /* The BH with the smaller ID will be merged onto the one with the larger ID
- */
- if (bj->id < bi->id) {
-
- message("ID is smaller");
+ /* The BH with the smaller mass will be merged onto the one with the
+ * larger mass.
+ * To avoid rounding issues, we additionally check for IDs if the BHs
+ * have the exact same mass. */
+ if ((bj->subgrid_mass < bi->subgrid_mass) ||
+ (bj->subgrid_mass == bi->subgrid_mass && bj->id < bi->id)) {
/* Merge if gravitationally bound
* Note that we use the kernel support here as the size and not just the
@@ -234,11 +235,15 @@ runner_iact_nonsym_bh_bh_swallow(const float r2, const float *dx,
/* This particle is swallowed by the BH with the largest ID of all the
* candidates wanting to swallow it */
- if (bj->merger_data.swallow_id < bi->id) {
+ if ((bj->merger_data.swallow_mass < bi->subgrid_mass) ||
+ (bj->merger_data.swallow_mass == bi->subgrid_mass &&
+ bj->merger_data.swallow_id < bi->id)) {
message("BH %lld wants to swallow BH particle %lld", bi->id, bj->id);
bj->merger_data.swallow_id = bi->id;
+ bj->merger_data.swallow_mass = bi->subgrid_mass;
+
} else {
message(
diff --git a/src/black_holes/EAGLE/black_holes_struct.h b/src/black_holes/EAGLE/black_holes_struct.h
index 96d9afd4d7..98f5380e9f 100644
--- a/src/black_holes/EAGLE/black_holes_struct.h
+++ b/src/black_holes/EAGLE/black_holes_struct.h
@@ -35,6 +35,9 @@ struct black_holes_bpart_data {
/*! ID of the black-hole that will swallow this #bpart. */
long long swallow_id;
+
+ /*! Mass of the black-hole that will swallow this #bpart. */
+ float swallow_mass;
};
/**
@@ -82,6 +85,7 @@ __attribute__((always_inline)) INLINE static void
black_holes_mark_bpart_as_not_swallowed(struct black_holes_bpart_data* p_data) {
p_data->swallow_id = -1;
+ p_data->swallow_mass = 0.f;
}
/**
@@ -94,6 +98,7 @@ __attribute__((always_inline)) INLINE static void
black_holes_mark_bpart_as_merged(struct black_holes_bpart_data* p_data) {
p_data->swallow_id = -2;
+ p_data->swallow_mass = -1.f;
}
/**
--
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