From d3331ea8c8f83bc7f059e2e52a288c54f7a2e069 Mon Sep 17 00:00:00 2001
From: Matthieu Schaller <matthieu.schaller@durham.ac.uk>
Date: Sat, 17 Mar 2018 12:14:45 +0100
Subject: [PATCH] Make use of the Plummer conversion constant for the time-step
 as well.

---
 src/gravity/Default/gravity.h | 4 ++--
 src/kernel_gravity.h          | 1 +
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/gravity/Default/gravity.h b/src/gravity/Default/gravity.h
index 292da62350..cace6e86bd 100644
--- a/src/gravity/Default/gravity.h
+++ b/src/gravity/Default/gravity.h
@@ -107,8 +107,8 @@ gravity_compute_timestep_self(const struct gpart* const gp,
   const float epsilon = gravity_get_softening(gp, grav_props);
 
   /* Note that 0.66666667 = 2. (from Gadget) / 3. (Plummer softening) */
-  const float dt =
-      sqrtf(0.66666667f * cosmo->a * grav_props->eta * epsilon * ac_inv);
+  const float dt = sqrtf(2. * kernel_gravity_softening_plummer_equivalent_inv *
+                         cosmo->a * grav_props->eta * epsilon * ac_inv);
 
   return dt;
 }
diff --git a/src/kernel_gravity.h b/src/kernel_gravity.h
index 5ccf14e5bb..dc9db63f9d 100644
--- a/src/kernel_gravity.h
+++ b/src/kernel_gravity.h
@@ -28,6 +28,7 @@
 
 /*! Conversion factor between Plummer softening and internal softening */
 #define kernel_gravity_softening_plummer_equivalent 3.
+#define kernel_gravity_softening_plummer_equivalent_inv (1. / 3.)
 
 /**
  * @brief Computes the gravity softening function for potential.
-- 
GitLab