From 4738e4be6ffb05e0821c5a22ad468dc6288ff21b Mon Sep 17 00:00:00 2001
From: David A Minton <daminton@purdue.edu>
Date: Wed, 12 Oct 2022 07:15:15 -0400
Subject: [PATCH] Fixed bug in RMVS that accidentally advanced system by two
 steps if there were no test particles

---
 src/rmvs/rmvs_step.f90 | 77 ++++++++++++++++++++++--------------------
 1 file changed, 40 insertions(+), 37 deletions(-)

diff --git a/src/rmvs/rmvs_step.f90 b/src/rmvs/rmvs_step.f90
index 76c5a802c..2b7e9045a 100644
--- a/src/rmvs/rmvs_step.f90
+++ b/src/rmvs/rmvs_step.f90
@@ -21,45 +21,48 @@ module subroutine rmvs_step_system(self, param, t, dt)
       real(DP), dimension(:,:), allocatable :: xbeg, xend, vbeg
       integer(I4B) :: i
 
-      if (self%tp%nbody == 0) call whm_step_system(self, param, t, dt)
-
-      select type(cb => self%cb)
-      class is (rmvs_cb)
-         select type(pl => self%pl)
-         class is (rmvs_pl)
-            select type(tp => self%tp)
-            class is (rmvs_tp)
-               associate(system => self, ntp => tp%nbody, npl => pl%nbody)
-                  allocate(xbeg, source=pl%xh)
-                  allocate(vbeg, source=pl%vh)
-                  call pl%set_beg_end(xbeg = xbeg, vbeg = vbeg)
-                  ! ****** Check for close encounters ***** !
-                  call pl%set_renc(RHSCALE)
-                  lencounter = tp%encounter_check(param, system, dt)
-                  if (lencounter) then
-                     lfirstpl = pl%lfirst
-                     pl%outer(0)%x(:, 1:npl) = xbeg(:, 1:npl)
-                     pl%outer(0)%v(:, 1:npl) = vbeg(:, 1:npl)
-                     call pl%step(system, param, t, dt) 
-                     pl%outer(NTENC)%x(:, 1:npl) = pl%xh(:, 1:npl)
-                     pl%outer(NTENC)%v(:, 1:npl) = pl%vh(:, 1:npl)
-                     call rmvs_interp_out(cb, pl, dt)
-                     call rmvs_step_out(cb, pl, tp, system, param, t, dt) 
-                     tp%lmask(1:ntp) = .not. tp%lmask(1:ntp)
-                     call pl%set_beg_end(xbeg = xbeg, xend = xend)
-                     tp%lfirst = .true.
-                     call tp%step(system, param, t, dt)
-                     tp%lmask(1:ntp) = .true.
-                     pl%lfirst = lfirstpl
-                     tp%lfirst = .true.
-                     if (param%ltides) call system%step_spin(param, t, dt)
-                  else
-                     call whm_step_system(system, param, t, dt)
-                  end if
-               end associate
+      if (self%tp%nbody == 0) then
+         call whm_step_system(self, param, t, dt)
+      else
+         select type(cb => self%cb)
+         class is (rmvs_cb)
+            select type(pl => self%pl)
+            class is (rmvs_pl)
+               select type(tp => self%tp)
+               class is (rmvs_tp)
+                  associate(system => self, ntp => tp%nbody, npl => pl%nbody)
+                     allocate(xbeg, source=pl%xh)
+                     allocate(vbeg, source=pl%vh)
+                     call pl%set_beg_end(xbeg = xbeg, vbeg = vbeg)
+                     ! ****** Check for close encounters ***** !
+                     call pl%set_renc(RHSCALE)
+                     lencounter = tp%encounter_check(param, system, dt)
+                     if (lencounter) then
+                        lfirstpl = pl%lfirst
+                        pl%outer(0)%x(:, 1:npl) = xbeg(:, 1:npl)
+                        pl%outer(0)%v(:, 1:npl) = vbeg(:, 1:npl)
+                        call pl%step(system, param, t, dt) 
+                        pl%outer(NTENC)%x(:, 1:npl) = pl%xh(:, 1:npl)
+                        pl%outer(NTENC)%v(:, 1:npl) = pl%vh(:, 1:npl)
+                        call rmvs_interp_out(cb, pl, dt)
+                        call rmvs_step_out(cb, pl, tp, system, param, t, dt) 
+                        tp%lmask(1:ntp) = .not. tp%lmask(1:ntp)
+                        call pl%set_beg_end(xbeg = xbeg, xend = xend)
+                        tp%lfirst = .true.
+                        call tp%step(system, param, t, dt)
+                        tp%lmask(1:ntp) = .true.
+                        pl%lfirst = lfirstpl
+                        tp%lfirst = .true.
+                        if (param%ltides) call system%step_spin(param, t, dt)
+                     else
+                        call whm_step_system(system, param, t, dt)
+                     end if
+                  end associate
+               end select
             end select
          end select
-      end select
+      end if
+
       return
    end subroutine rmvs_step_system