Reformatted code to pull use statements out of individual subroutines in the submodules due to complains from ifort. Also cleaned up some cruft

src/discard/discard.f90

@@ -1,23 +1,23 @@
 submodule (swiftest_classes) s_discard
+   use swiftest
 contains
-   module procedure discard_system
+   module subroutine discard_system(self, config)
       !! author: David A. Minton
       !!
       !! Check to see if particles should be discarded based on their positions relative to the massive bodies
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: discard.f90
       !! Adapted from Hal Levison's Swift routine discard.f
-      use swiftest
       implicit none
-      logical, dimension(:), allocatable :: lspill_list
+      class(swiftest_nbody_system),  intent(inout) :: self    !! Swiftest system object
+      class(swiftest_configuration), intent(in)    :: config  !! Input collection of  configuration parameters
 
-      real(DP) :: msys
       if (self%tp%nbody == 0) return 
       select type(self)
       class is (whm_nbody_system)
          associate(cb => self%cb, pl => self%pl, tp => self%tp, t => config%t, dt => config%dt, &
                    msys => self%msys, discards => self%tp_discards, &
-                   ntp => self%tp%nbody)
+                   ntp => self%tp%nbody, ldiscard => self%tp%ldiscard)
             if ((config%rmin >= 0.0_DP) .or. (config%rmax >= 0.0_DP) .or. &
                (config%rmaxu >= 0.0_DP) .or. ((config%qmin >= 0.0_DP) .and. (config%qmin_coord == "BARY"))) then
                   call pl%h2b(cb) 
@@ -27,29 +27,34 @@
                if (ntp > 0) call tp%discard_sun(cb, config, t, msys)
             end if
             if (config%qmin >= 0.0_DP .and. ntp > 0) call tp%discard_peri(cb, pl, config, t, msys)
-            if (config%lclose .and. ntp > 0) call tp%discard_pl(cb, pl, config, t, dt)
+            if (config%lclose .and. ntp > 0) call tp%discard_pl(pl, t, dt)
 
             if (any(tp%ldiscard(1:ntp))) then
                ! Spill the discards to the spill list
-               allocate(lspill_list, source = tp%ldiscard)
-               call tp%spill(discards, lspill_list) 
+               call tp%spill(discards, ldiscard)
                call self%write_discard(config, discards)
-               deallocate(lspill_list)
             end if
          end associate  
          end select
       return
-   end procedure discard_system
+   end subroutine discard_system
 
-   module procedure discard_sun_tp 
+   module subroutine discard_sun_tp(self, cb, config, t, msys)
       !! author: David A. Minton
       !!
       !!  Check to see if test particles should be discarded based on their positions relative to the Sun
       !!        or because they are unbound from the system
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: discard_sun.f90
       !! Adapted from Hal Levison's Swift routine discard_sun.f
-      use swiftest
+      implicit none
+      ! Arguments
+      class(swiftest_tp),            intent(inout) :: self   !! Swiftest test particle object
+      class(swiftest_cb),            intent(inout) :: cb     !! Swiftest central body object
+      class(swiftest_configuration), intent(in)    :: config !!  configuration parameters
+      real(DP),                      intent(in)    :: t      !! Current simulation tim
+      real(DP),                      intent(in)    :: msys   !! Total system mass
+      ! Internals
       integer(I4B)        :: i
       real(DP)            :: energy, vb2, rb2, rh2, rmin2, rmax2, rmaxu2
 
@@ -83,23 +88,29 @@
       end associate
 
       return
-
-   end procedure discard_sun_tp
+   end subroutine discard_sun_tp
 
-   module procedure discard_peri_tp
+   module subroutine discard_peri_tp(self, cb, pl, config, t, msys)
       !! author: David A. Minton
       !!
       !! Check to see if a test particle should be discarded because its perihelion distance becomes too small
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: discard_peri.f90
       !! Adapted from Hal Levison's Swift routine discard_peri.f
-      use swiftest
+      implicit none
+      ! Arguments
+      class(swiftest_tp),            intent(inout) :: self   !! Swiftest test particle object
+      class(swiftest_cb),            intent(inout) :: cb     !! Swiftest central body object
+      class(swiftest_pl),            intent(inout) :: pl     !! Swiftest massive body object
+      class(swiftest_configuration), intent(in)    :: config !!  configuration parameters
+      real(DP),                      intent(in)    :: t      !! Current simulation tim
+      real(DP),                      intent(in)    :: msys   !! Total system mass 
+      ! Internals
       logical, save             :: lfirst = .true.
-      integer(I4B)              :: i, j, ih, ntp, npl
+      integer(I4B)              :: i, j, ih
       real(DP)                  :: r2
       real(DP), dimension(NDIM) :: dx
 
-
       associate(tp => self, ntp => self%nbody, npl => pl%nbody, qmin_coord => config%qmin_coord)
          if (lfirst) then
             call util_hills(npl, pl)
@@ -132,19 +143,23 @@
       end associate
       return
 
-   end procedure discard_peri_tp
+   end subroutine discard_peri_tp
 
-   module procedure discard_pl_tp
+   module subroutine discard_pl_tp(self, pl, t, dt)
       !! author: David A. Minton
       !!
       !! Check to see if test particles should be discarded based on their positions relative to the massive bodies
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: discard_pl.f90
       !! Adapted from Hal Levison's Swift routine discard_pl.f
-      use swiftest
       implicit none
-
-      integer(I4B)              :: i, j, isp, ntp, npl
+      ! Arguments
+      class(swiftest_tp),            intent(inout) :: self   !! Swiftest test particle object
+      class(swiftest_pl),            intent(inout) :: pl     !! Swiftest massive body object
+      real(DP),                      intent(in)    :: t      !! Current simulation tim
+      real(DP),                      intent(in)    :: dt     !! Stepsize
+      ! Internals 
+      integer(I4B)              :: i, j, isp
       real(DP)                  :: r2min, radius
       real(DP), dimension(NDIM) :: dx, dv
 
@@ -170,19 +185,25 @@
       end associate
       return
 
-   end procedure discard_pl_tp
+   end subroutine discard_pl_tp
 
-   module procedure discard_pl_close
+   module subroutine discard_pl_close(dx, dv, dt, r2crit, iflag, r2min)
       !! author: David A. Minton
       !!
       !!  Check to see if a test particle and massive body are having, or will have within the next time step, an encounter such
       !!          that the separation distance r is less than some critical radius rcrit (or r**2 < rcrit**2 = r2crit)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: discard_pl_close.f90
       !! Adapted from Hal Levison's Swift routine discard_pl_close.f
-      use swiftest
+      implicit none
+      ! Arguments
+      real(DP), dimension(:), intent(in)    :: dx, dv
+      real(DP), intent(in)                  :: dt, r2crit
+      integer(I4B), intent(out)             :: iflag
+      real(DP), intent(out)                 :: r2min
+      ! Internals
       real(DP) :: r2, v2, vdotr, tmin
-
+      
       r2 = dot_product(dx(:), dx(:))
       if (r2 <= r2crit) then
          iflag = 1
@@ -208,7 +229,6 @@
       end if
 
       return
-
-      end procedure discard_pl_close
+   end subroutine discard_pl_close
 
 end submodule s_discard

src/driftkick/drift.f90

@@ -1,5 +1,5 @@
 submodule (swiftest_classes) drift_implementation
-
+   use swiftest
    !> Integration control parameters:
    real(DP), parameter :: E2MAX    = 0.36_DP      
    real(DP), parameter :: DM2MAX   = 0.16_DP
@@ -16,7 +16,6 @@ module pure subroutine drift_one(mu, x, v, dt, iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine routine drift_one.f90
       !! Adapted from Hal Levison and Martin Duncan's Swift routine drift_one.f
-      use swiftest_globals
       implicit none
       ! Arguments
       real(DP), intent(in)                   :: mu    !! G * (Mcb + m), G = gravitational constant, Mcb = mass of central body, m = mass of body to drift
@@ -46,7 +45,6 @@ pure subroutine drift_dan(mu, x0, v0, dt0, iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_dan.f90
       !! Adapted from Hal Levison and Martin Duncan's Swift routine drift_dan.f
-      use swiftest
       implicit none
       integer(I4B), intent(out)                :: iflag
       real(DP), intent(in)                     :: mu, dt0
@@ -118,7 +116,6 @@ pure subroutine drift_kepmd(dm, es, ec, x, s, c)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepmd.f90
       !! Adapted from Martin Duncan's Swift routine drift_kepmd.f
-      use swiftest
       implicit none
       real(DP), intent(in)  :: dm, es, ec
       real(DP), intent(out) :: x, s, c      
@@ -155,7 +152,6 @@ pure subroutine drift_kepu(dt,r0,mu,alpha,u,fp,c1,c2,c3,iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu.f90
       !! Adapted from Hal Levison's Swift routine drift_kepu.f
-      use swiftest
       implicit none
       integer(I4B), intent(out) :: iflag
       real(DP), intent(in)      :: dt, r0, mu, alpha, u
@@ -183,7 +179,6 @@ pure subroutine drift_kepu_fchk(dt, r0, mu, alpha, u, s, f)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_fchk.f90
       !! Adapted from Martin Duncan's Swift routine drift_kepu_fchk.f
-      use swiftest
       implicit none
       real(DP), intent(in)  :: dt, r0, mu, alpha, u, s
       real(DP), intent(out) :: f
@@ -206,7 +201,6 @@ pure subroutine drift_kepu_guess(dt, r0, mu, alpha, u, s)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_guess.f90
       !! Adapted from Hal Levison and Martin Duncan's Swift routine drift_kepu_guess.f
-      use swiftest
       implicit none
       real(DP), intent(in)  :: dt, r0, mu, alpha, u
       real(DP), intent(out) :: s      
@@ -245,7 +239,6 @@ pure subroutine drift_kepu_lag(s, dt, r0, mu, alpha, u, fp, c1, c2, c3, iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_lag.f90
       !! Adapted from Hal Levison's Swift routine drift_kepu_lag.f
-      use swiftest
       implicit none
       integer(I4B), intent(out) :: iflag
       real(DP), intent(in)      :: dt, r0, mu, alpha, u
@@ -290,7 +283,6 @@ pure subroutine drift_kepu_new(s, dt, r0, mu, alpha, u, fp, c1, c2, c3, iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_new.f90
       !! Adapted from Hal Levison's Swift routine drift_kepu_new.f
-      use swiftest
       implicit none
       integer(I4B), intent(out) :: iflag
       real(DP), intent(in)      :: dt, r0, mu, alpha, u
@@ -332,7 +324,6 @@ pure subroutine drift_kepu_p3solve(dt, r0, mu, alpha, u, s, iflag)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_p3solve.f90
       !! Adapted from Martin Duncan's Swift routine drift_kepu_p3solve.f
-      use swiftest
       implicit none
       integer(I4B), intent(out) :: iflag
       real(DP), intent(in)      :: dt, r0, mu, alpha, u
@@ -376,7 +367,6 @@ pure subroutine drift_kepu_stumpff(x, c0, c1, c2, c3)
       !!
       !! Adapted from David E. Kaufmann's Swifter routine: drift_kepu_stumpff.f90
       !! Adapted from Hal Levison's Swift routine drift_kepu_stumpff.f
-      use swiftest
       implicit none
       real(DP), intent(inout) :: x
       real(DP), intent(out)   :: c0, c1, c2, c3

src/driftkick/kick.f90

@@ -1,36 +1,42 @@
 submodule(swiftest_classes) s_kick
-contains
-   module procedure kick_vh_body 
-   !! author: David A. Minton
-   !!
-   !! Kick heliocentric velocities of bodies
-   !!
-   !! Adapted from Martin Duncan and Hal Levison's Swift routine kickvh.f and kickvh_tp.f
-   !! Adapted from David E. Kaufmann's Swifter routine whm_kickvh.f90 and whm_kickvh_tp.f90
    use swiftest
-   implicit none
-   integer(I4B) :: i
-
-   associate(n => self%nbody, vh => self%vh, ah => self%ah, status => self%status)
-      if (n == 0) return
-      do concurrent(i = 1:n, status(i) == ACTIVE) 
-         vh(:, i) = vh(:, i) + ah(:, i) * dt
-      end do
-   end associate
+contains
+   module subroutine kick_vh_body(self, dt)
+      !! author: David A. Minton
+      !!
+      !! Kick heliocentric velocities of bodies
+      !!
+      !! Adapted from Martin Duncan and Hal Levison's Swift routine kickvh.f and kickvh_tp.f
+      !! Adapted from David E. Kaufmann's Swifter routine whm_kickvh.f90 and whm_kickvh_tp.f90
+      implicit none
+      ! Arguments
+      class(swiftest_body),         intent(inout) :: self !! Swiftest generic body object
+      real(DP),                     intent(in)    :: dt   !! Stepsize
+      ! Internals
+      integer(I4B) :: i
 
-   return
+      associate(n => self%nbody, vh => self%vh, ah => self%ah, status => self%status)
+         if (n == 0) return
+         do concurrent(i = 1:n, status(i) == ACTIVE) 
+            vh(:, i) = vh(:, i) + ah(:, i) * dt
+         end do
+      end associate
 
-   end procedure kick_vh_body
+      return
+   end subroutine kick_vh_body
 
-   module procedure kick_vb_body 
+   module subroutine kick_vb_body(self, dt)
       !! author: David A. Minton
       !!
       !! Kick barycentric velocities of bodies
       !!
       !! Adapted from Martin Duncan and Hal Levison's Swift routine kickvh.f and kickvh_tp.f
       !! Adapted from David E. Kaufmann's Swifter routine helio_kickvb.f90 and helio_kickvb_tp.f90
-      use swiftest
       implicit none
+      ! Arguments
+      class(swiftest_body),         intent(inout) :: self !! Swiftest generic body object
+      real(DP),                     intent(in)    :: dt   !! Stepsize
+      ! Internals
       integer(I4B) :: i
 
       associate(n => self%nbody, vb => self%vb, ah => self%ah, status => self%status)
@@ -42,5 +48,5 @@
 
       return
 
-      end procedure kick_vb_body
+   end subroutine kick_vb_body
 end submodule s_kick

src/eucl/eucl.f90

@@ -1,6 +1,6 @@
 submodule (swiftest_classes) s_eucl
+   use swiftest
 contains
-
    module procedure eucl_dist_index_plpl
       !! author: Jacob R. Elliott and David A. Minton
       !!
@@ -10,7 +10,6 @@
       !!
       !!    Mélodie Angeletti, Jean-Marie Bonny, Jonas Koko. Parallel Euclidean distance matrix computation on big datasets *. 
       !!       2019. hal-0204751
-      use swiftest
       implicit none
 
       integer(I4B) :: i, j, k, kp, p
@@ -41,7 +40,6 @@
       !! author: Jacob R. Elliott and David A. Minton
       !!
       !! Efficient parallel loop-blocking algrorithm for evaluating the Euclidean distance matrix for planet-planet
-      use swiftest
       implicit none
       integer(I4B) :: k, i, j
       real(DP), dimension(NDIM) :: dx

src/gr/gr.f90

@@ -1,14 +1,13 @@
 submodule(swiftest_classes) s_gr
+   use swiftest
 contains
-
    module procedure gr_getaccb_ns_body
       !! author: David A. Minton
       !!
       !! Add relativistic correction acceleration for non-symplectic integrators
       !!    Based on Quinn, Tremaine, & Duncan 1998
       !!
       !! Adapted from David A. Minton's Swifter routine routine gr_getaccb_ns.f90
-      use swiftest
       implicit none
 
       real(DP), dimension(NDIM) :: xh, vh