From 1f166e46a0909b0a0466f9eee36bdae128262f53 Mon Sep 17 00:00:00 2001
From: Matthieu Schaller <matthieu.schaller@durham.ac.uk>
Date: Sat, 9 Jun 2018 14:57:21 +0200
Subject: [PATCH] Corrected typo in 5th order derivative of Chi in the Gadget-2
 trunctation formula.

---
 examples/ZeldovichPancake_3D/zeldovichPancake.yml | 2 +-
 src/kernel_long_gravity.h                         | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/examples/ZeldovichPancake_3D/zeldovichPancake.yml b/examples/ZeldovichPancake_3D/zeldovichPancake.yml
index ec20a7121f..d0bbe55222 100644
--- a/examples/ZeldovichPancake_3D/zeldovichPancake.yml
+++ b/examples/ZeldovichPancake_3D/zeldovichPancake.yml
@@ -47,6 +47,6 @@ Gravity:
   mesh_side_length:   16
   eta: 0.025
   theta: 0.85
-  r_cut_max: 6.
+  r_cut_max: 5.
   comoving_softening: 0.0001
   max_physical_softening: 0.0001
diff --git a/src/kernel_long_gravity.h b/src/kernel_long_gravity.h
index 0adfcb303d..882575e437 100644
--- a/src/kernel_long_gravity.h
+++ b/src/kernel_long_gravity.h
@@ -67,7 +67,7 @@ __attribute__((always_inline)) INLINE static void kernel_long_grav_derivatives(
   derivs->chi_2 = rs_inv2 * u;
   derivs->chi_3 = -rs_inv3 * (u2 - 0.5f);
   derivs->chi_4 = rs_inv4 * (u3 - 1.5f * u);
-  derivs->chi_5 = -rs_inv5 * (u4 - u2 + 0.75f);
+  derivs->chi_5 = -rs_inv5 * (u4 - 3.f * u2 + 0.75f);
 
   const float one_over_sqrt_pi = ((float)(M_2_SQRTPI * 0.5));
   const float common_factor = one_over_sqrt_pi * expf(-u2);
-- 
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