From 26022c4ce0bde62a7bbe02dd2cce717875502f51 Mon Sep 17 00:00:00 2001
From: Grzegorz Kowal <grzegorz@amuncode.org>
Date: Tue, 29 Aug 2023 17:43:03 -0300
Subject: [PATCH] EVOLUTION, FORCING: Add injected flag to update_forcing().

This flag indicates whether the energy injection was performed. If not,
there is no need for the variable update.

Signed-off-by: Grzegorz Kowal <grzegorz@amuncode.org>
---
 sources/evolution.F90 | 10 +++++---
 sources/forcing.F90   | 55 ++++++++++++++++++++++++++++++-------------
 2 files changed, 45 insertions(+), 20 deletions(-)

diff --git a/sources/evolution.F90 b/sources/evolution.F90
index a847cf5..b0ff270 100644
--- a/sources/evolution.F90
+++ b/sources/evolution.F90
@@ -1097,6 +1097,8 @@ module evolution
 
     integer, intent(out) :: status
 
+    logical :: injected
+
 !-------------------------------------------------------------------------------
 !
 ! advance the solution using the selected method
@@ -1106,10 +1108,12 @@ module evolution
 ! add forcing contribution, requires the boundary and primitive variable update
 !
     if (forcing_enabled) then
-      call update_forcing(time, dt)
+      call update_forcing(time, dt, injected)
 
-      call update_variables(time + dt, 0.0d+00, status)
-      if (status /= 0) go to 100
+      if (injected) then
+        call update_variables(time + dt, 0.0d+00, status)
+        if (status /= 0) go to 100
+      end if
     end if
 
 ! check if we need to perform the refinement step
diff --git a/sources/forcing.F90 b/sources/forcing.F90
index 2a9f53e..a577bca 100644
--- a/sources/forcing.F90
+++ b/sources/forcing.F90
@@ -35,8 +35,9 @@ module forcing
 ! interfaces for procedure pointers
 !
   abstract interface
-    subroutine update_forcing_iface(t, dt)
-      real(kind=8), intent(in) :: t, dt
+    subroutine update_forcing_iface(t, dt, injected)
+      real(kind=8), intent(in   ) :: t, dt
+      logical     , intent(  out) :: injected
     end subroutine
   end interface
 
@@ -969,23 +970,25 @@ module forcing
 ! subroutine UPDATE_FORCING_EDDIES:
 ! --------------------------------
 !
-!   Subroutine adds the energy injection terms.
+!   This subroutine adds the energy injection terms using simple eddy mixing.
 !
 !   Arguments:
 !
-!     t  - time;
-!     dt - time step;
+!     t        - time;
+!     dt       - time step;
+!     injected - flag indicating whether the injection was performed;
 !
 !===============================================================================
 !
-  subroutine update_forcing_eddies(t, dt)
+  subroutine update_forcing_eddies(t, dt, injected)
 
     use coordinates, only : xmin, ymin, zmin, xlen, ylen, zlen
     use random     , only : randuni, randsym
 
     implicit none
 
-    real(kind=8), intent(in) :: t, dt
+    real(kind=8), intent(in   ) :: t, dt
+    logical     , intent(  out) :: injected
 
     integer                    :: ni, n
 #if NDIMS == 3
@@ -995,6 +998,8 @@ module forcing
 
 !-------------------------------------------------------------------------------
 !
+    injected = .false.
+
     if (t < tinj_start .or. t > tinj_stop) then
       arms = 0.0d+00
       dinj = 0.0d+00
@@ -1042,6 +1047,8 @@ module forcing
 
       end do
 
+      injected = .true.
+
     end if
 
 !-------------------------------------------------------------------------------
@@ -1053,16 +1060,18 @@ module forcing
 ! subroutine UPDATE_FORCING_OH:
 ! ----------------------------
 !
-!   Subroutine adds the energy injection terms for Ornstein–Uhlenbeck driving.
+!   This subroutine adds the energy injection terms using Ornstein–Uhlenbeck
+!   driving.
 !
 !   Arguments:
 !
-!     t  - time;
-!     dt - time step;
+!     t        - time;
+!     dt       - time step;
+!     injected - flag indicating whether the injection was performed;
 !
 !===============================================================================
 !
-  subroutine update_forcing_oh(t, dt)
+  subroutine update_forcing_oh(t, dt, injected)
 
 #if NDIMS == 3
     use constants, only : pi2
@@ -1071,7 +1080,8 @@ module forcing
 
     implicit none
 
-    real(kind=8), intent(in) :: t, dt
+    real(kind=8), intent(in   ) :: t, dt
+    logical     , intent(  out) :: injected
 
     integer      :: l
     real(kind=8) :: acoeff, dcoeff
@@ -1084,6 +1094,8 @@ module forcing
 
 !-------------------------------------------------------------------------------
 !
+    injected = .false.
+
     if (t < tinj_start .or. t > tinj_stop) then
       arms = 0.0d+00
       dinj = 0.0d+00
@@ -1136,6 +1148,8 @@ module forcing
 !
     rinj = dinj / dt
 
+    injected = .true.
+
 !-------------------------------------------------------------------------------
 !
   end subroutine update_forcing_oh
@@ -1145,23 +1159,26 @@ module forcing
 ! subroutine UPDATE_FORCING_ALVELIUS:
 ! ----------------------------------
 !
-!   Subroutine adds the energy injection terms for Alvelius driving.
+!   This subroutine adds the energy injection terms using Alvelius
+!   driving.
 !
 !   Arguments:
 !
-!     t  - time;
-!     dt - time step;
+!     t        - time;
+!     dt       - time step;
+!     injected - flag indicating whether the injection was performed;
 !
 !===============================================================================
 !
-  subroutine update_forcing_alvelius(t, dt)
+  subroutine update_forcing_alvelius(t, dt, injected)
 
     use constants, only : pi2
     use random   , only : randuni
 
     implicit none
 
-    real(kind=8), intent(in) :: t, dt
+    real(kind=8), intent(in   ) :: t, dt
+    logical     , intent(  out) :: injected
 
     integer         :: l
     real(kind=8)    :: th1, dinj, sqdt
@@ -1176,6 +1193,8 @@ module forcing
 
 !-------------------------------------------------------------------------------
 !
+    injected = .false.
+
     if (t < tinj_start .or. t > tinj_stop) then
       arms = 0.0d+00
       dinj = 0.0d+00
@@ -1258,6 +1277,8 @@ module forcing
 !
     rinj = dinj / dt
 
+    injected = .true.
+
 !-------------------------------------------------------------------------------
 !
   end subroutine update_forcing_alvelius