From 6109d9dba1cd232ad64cdec83b42158f27ad89f2 Mon Sep 17 00:00:00 2001
From: JeroBnd <135150267+JeroBnd@users.noreply.github.com>
Date: Thu, 12 Sep 2024 09:57:35 -0300
Subject: [PATCH 1/2] Fixed the source of the dt=0 error when using adaptive
 time step  in idealized cases

Restrict the remaining time until the next boundary control to be greater than 0 in order to correct the dtInterval.
---
 dyn_em/adapt_timestep_em.F | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/dyn_em/adapt_timestep_em.F b/dyn_em/adapt_timestep_em.F
index 2de49b12d7..23ab732794 100644
--- a/dyn_em/adapt_timestep_em.F
+++ b/dyn_em/adapt_timestep_em.F
@@ -287,8 +287,10 @@ RECURSIVE SUBROUTINE adapt_timestep(grid, config_flags)
   num = INT(time_to_bc * precision + 0.5)
   den = precision
   CALL WRFU_TimeIntervalSet(tmpTimeInterval, Sn=num, Sd=den)
-  
-  if ( ( tmpTimeInterval .LT. dtInterval * 2 ) .and. &
+
+if (num .LE. 0) then
+     stepping_to_bc = .false.
+  elseif ( ( tmpTimeInterval .LT. dtInterval * 2 ) .and. &
        ( tmpTimeInterval .GT. dtInterval ) ) then
      dtInterval = tmpTimeInterval / 2
      

From aed98f6a93360940e08f57d8797796403b237ff2 Mon Sep 17 00:00:00 2001
From: JeroBnd <135150267+JeroBnd@users.noreply.github.com>
Date: Thu, 12 Sep 2024 12:52:32 -0300
Subject: [PATCH 2/2] Fix the dtInterval adjunstment on output time using
 adaptive

Problems with the precision of the time_to_output calculation cause errors in setting the correct time step at output time and final time in the em_b_wave ideal test
---
 dyn_em/adapt_timestep_em.F | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/dyn_em/adapt_timestep_em.F b/dyn_em/adapt_timestep_em.F
index 23ab732794..d96bfb037c 100644
--- a/dyn_em/adapt_timestep_em.F
+++ b/dyn_em/adapt_timestep_em.F
@@ -288,7 +288,7 @@ RECURSIVE SUBROUTINE adapt_timestep(grid, config_flags)
   den = precision
   CALL WRFU_TimeIntervalSet(tmpTimeInterval, Sn=num, Sd=den)
 
-if (num .LE. 0) then
+  if (num .LE. 0) then
      stepping_to_bc = .false.
   elseif ( ( tmpTimeInterval .LT. dtInterval * 2 ) .and. &
        ( tmpTimeInterval .GT. dtInterval ) ) then
@@ -327,34 +327,26 @@ RECURSIVE SUBROUTINE adapt_timestep(grid, config_flags)
      history_interval_sec = grid%history_interval_s + grid%history_interval_m*60 + &
                             grid%history_interval_h*3600 + grid%history_interval_d*86400
 
-     time_to_output = history_interval_sec - &
-          mod( curr_secs, REAL(history_interval_sec) )
-     num = INT(time_to_output * precision + 0.5)
+     num = INT(history_interval_sec * precision + 0.5)
      den = precision
-     call WRFU_TimeIntervalSet(tmpTimeInterval, Sn=num, Sd=den)
+     CALL WRFU_TimeIntervalSet(tmpTimeInterval, Sn=num, Sd=den)
+
+     !Calc the time to output
+     tmpTimeInterval = tmpTimeInterval * (INT(curr_secs / REAL(history_interval_sec))+1) - &
+                      (domain_get_current_time ( grid ) - domain_get_start_time ( grid ) )
 
      if ( ( tmpTimeInterval .LT. dtInterval * 2 ) .and. &
           ( tmpTimeInterval .GT. dtInterval ) ) then
-        dtInterval = tmpTimeInterval / 2
+        
+        num = INT(( real_time(tmpTimeInterval) * precision)/2 + 0.5)
+        den = precision
+        call WRFU_TimeIntervalSet(dtInterval, Sn=num, Sd=den)
+
         use_last2 = .TRUE.
         grid%stepping_to_time = .TRUE.
 
      elseif (tmpTimeInterval .LE. dtInterval) then
-        !
-        ! We will do some tricks here to assure that we fall exactly on an 
-        !   output time.  Without the tricks, round-off error causes problems!
-        !
-
-        !
-        ! Calculate output time.  We round to nearest history time to assure 
-        !    we don't have any rounding error.
-        !
-        output_time = NINT ( (curr_secs + time_to_output) /  &
-             (history_interval_sec) ) * (history_interval_sec)
-        CALL WRFU_TimeIntervalSet(tmpTimeInterval, S=output_time)
-        dtInterval = tmpTimeInterval - &
-             (domain_get_current_time(grid) - domain_get_start_time(grid))
-
+        dtInterval = tmpTimeInterval
         use_last2 = .TRUE.
         grid%stepping_to_time = .TRUE.
      endif