From 592f1e59aa9e5dc48e20fdbac86f2d307f6c95e8 Mon Sep 17 00:00:00 2001
From: anand43 <anand43@purdue.edu>
Date: Thu, 25 Jan 2024 13:52:18 -0500
Subject: [PATCH] Skip calculation of kick if c_lm = 0; to improve performance

---
 src/swiftest/swiftest_sph.f90 | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/swiftest/swiftest_sph.f90 b/src/swiftest/swiftest_sph.f90
index 2def11b02..a84376038 100644
--- a/src/swiftest/swiftest_sph.f90
+++ b/src/swiftest/swiftest_sph.f90
@@ -72,6 +72,11 @@ module subroutine swiftest_sph_g_acc_one(GMcb, r_0, phi_cb, rh, c_lm, g_sph, GMp
         do l = 1, l_max ! skipping the l = 0 term; It is the spherical body term
             do m = 0, l
 
+                ! If c_lm is too small, skip the iteration to improve performance
+                if (abs(c_lm(m+1, l+1, 1)) < epsilon(0.0_DP) .and. abs(c_lm(m+1, l+1, 2)) < epsilon(0.0_DP)) then
+                    cycle  
+                endif
+
                 ! Associated Legendre Polynomials 
                 lmindex = PlmIndex(l, m)  
                 plm = p(lmindex)                  ! p_l,m