Devels Frediani

physics/fire_model_mod.F90

@@ -2,7 +2,7 @@ module fire_model_mod
 
     use fire_physics_mod, only: Calc_flame_length, Calc_fire_fluxes, Calc_smoke_emissions
     use level_set_mod, only: Calc_fuel_left, Update_ignition_times, Reinit_level_set, Prop_level_set, Extrapol_var_at_bdys, &
-        Stop_if_close_to_bdy, Copy_lfnout_to_lfn, Reinit_level_set_fast_dist
+        Stop_if_close_to_bdy, Copy_lfnout_to_lfn, Reinit_level_set_fast_dist, Check_isolated_negative_lfn
     use namelist_mod, only : namelist_t
     use ros_mod, only : ros_t
     use state_mod, only: state_fire_t, N_POINTS_IN_HALO
@@ -29,6 +29,7 @@ subroutine Advance_fire_model (config_flags, grid)
 
       integer :: ij, ifds, ifde, jfds, jfde, ifts, ifte, jfts, jfte, ifms, ifme, jfms, jfme
       real :: tbound, time_start
+      integer, parameter :: CHECK_ISOLATED_NEG_LFN = 0
       logical, parameter :: DEBUG_LOCAL = .false.
 
 
@@ -130,6 +131,8 @@ subroutine Advance_fire_model (config_flags, grid)
 #ifdef DM_PARALLEL
       call Do_halo_exchange_with_corners (grid%lfn, ifms, ifme, jfms, jfme, grid%ifps, grid%ifpe, grid%jfps, grid%jfpe, N_POINTS_IN_HALO, grid%cart_comm)
 #endif
+
+      if (CHECK_ISOLATED_NEG_LFN == 1) call Check_isolated_negative_lfn (grid)
 
       if (DEBUG_LOCAL) call Print_message ('calling Ignite_prescribed_fires...')
       !$OMP PARALLEL DO   &

physics/level_set_mod.F90

@@ -20,15 +20,15 @@ module level_set_mod
     use ros_mod, only : ros_t
 
 #ifdef DM_PARALLEL
-    use mpi_mod, only : Do_halo_exchange
+    use mpi_mod, only : Do_halo_exchange, Sum_across_mpi_tasks, Max_across_mpi_tasks
 #endif
 
     implicit none
 
     private
 
     public :: Calc_fuel_left, Update_ignition_times, Reinit_level_set, Prop_level_set, Extrapol_var_at_bdys, Stop_if_close_to_bdy, &
-        Copy_lfnout_to_lfn, Reinit_level_set_fast_dist
+        Copy_lfnout_to_lfn, Reinit_level_set_fast_dist, Check_isolated_negative_lfn
 
     integer, parameter :: BDY_ENO1 = 10, FAST_DIST_REINIT_FSM = 1
     integer, parameter :: FAR = 0, TRIAL = 1, KNOWN = 2
@@ -291,6 +291,137 @@ pure subroutine Copy_lfnout_to_lfn (ifts, ifte, jfts, jfte, ifms, ifme, jfms, jf
 
     end subroutine Copy_lfnout_to_lfn
 
+    subroutine Check_isolated_negative_lfn (grid, threshold, min_size, max_size)
+
+      implicit none
+
+      type (state_fire_t), intent (in out) :: grid
+      real, intent (in), optional :: threshold
+      integer, intent (in), optional :: min_size, max_size
+
+      character (len = 256) :: msg
+      integer :: cluster_i, cluster_j, cluster_size, flagged_size
+      integer :: head, tail, i, ic, inb, j, jc, jnb, max_queue, min_size_value, max_size_value
+      integer :: nx_loc, ny_loc
+      logical :: found_cluster, touches_boundary
+      logical, dimension(:, :), allocatable :: visited
+      integer, dimension(:), allocatable :: queue_i, queue_j
+      real :: detection_flag, detection_sum, global_location_i, global_location_j, global_size_value
+      real :: location_i, location_j, size_value, threshold_value
+
+
+      threshold_value = 0.0
+      if (present (threshold)) threshold_value = threshold
+
+      min_size_value = 1
+      if (present (min_size)) min_size_value = min_size
+
+      max_size_value = 6
+      if (present (max_size)) max_size_value = max_size
+
+      if (max_size_value < min_size_value) return
+
+      nx_loc = grid%ifpe - grid%ifps + 1
+      ny_loc = grid%jfpe - grid%jfps + 1
+      if (nx_loc <= 0 .or. ny_loc <= 0) return
+      max_queue = nx_loc * ny_loc
+
+      allocate (visited(grid%ifps:grid%ifpe, grid%jfps:grid%jfpe))
+      allocate (queue_i(max_queue))
+      allocate (queue_j(max_queue))
+
+      visited = .false.
+      found_cluster = .false.
+      flagged_size = 0
+      cluster_i = grid%ifps
+      cluster_j = grid%jfps
+
+      Cluster_search: do j = grid%jfps, grid%jfpe
+        do i = grid%ifps, grid%ifpe
+          if (visited(i, j)) cycle
+          visited(i, j) = .true.
+          if (grid%lfn(i, j) >= threshold_value) cycle
+
+          head = 1
+          tail = 1
+          queue_i(1) = i
+          queue_j(1) = j
+          cluster_size = 0
+          touches_boundary = .false.
+
+          do while (head <= tail)
+            ic = queue_i(head)
+            jc = queue_j(head)
+            head = head + 1
+
+            cluster_size = cluster_size + 1
+            if (ic == grid%ifps .or. ic == grid%ifpe .or. jc == grid%jfps .or. jc == grid%jfpe) touches_boundary = .true.
+
+            do jnb = jc - 1, jc + 1
+              do inb = ic - 1, ic + 1
+                if (inb == ic .and. jnb == jc) cycle
+                if (inb < grid%ifps .or. inb > grid%ifpe) cycle
+                if (jnb < grid%jfps .or. jnb > grid%jfpe) cycle
+                if (visited(inb, jnb)) cycle
+                visited(inb, jnb) = .true.
+                if (grid%lfn(inb, jnb) >= threshold_value) cycle
+
+                tail = tail + 1
+                queue_i(tail) = inb
+                queue_j(tail) = jnb
+              end do
+            end do
+          end do
+
+          if (cluster_size >= min_size_value .and. cluster_size <= max_size_value .and. .not. touches_boundary) then
+            found_cluster = .true.
+            flagged_size = cluster_size
+            cluster_i = i
+            cluster_j = j
+            exit Cluster_search
+          end if
+        end do
+      end do Cluster_search
+
+      deallocate (visited)
+      deallocate (queue_i)
+      deallocate (queue_j)
+
+      detection_flag = 0.0
+      location_i = -1.0
+      location_j = -1.0
+      size_value = -1.0
+      if (found_cluster) then
+        detection_flag = 1.0
+        location_i = real (cluster_i)
+        location_j = real (cluster_j)
+        size_value = real (flagged_size)
+      end if
+
+#ifdef DM_PARALLEL
+      call Sum_across_mpi_tasks (detection_flag, grid%cart_comm, detection_sum)
+      call Max_across_mpi_tasks (location_i, grid%cart_comm, global_location_i)
+      call Max_across_mpi_tasks (location_j, grid%cart_comm, global_location_j)
+      call Max_across_mpi_tasks (size_value, grid%cart_comm, global_size_value)
+#else
+      detection_sum = detection_flag
+      global_location_i = location_i
+      global_location_j = location_j
+      global_size_value = size_value
+#endif
+
+      if (detection_sum > 0.0) then
+        grid%datetime_now = grid%datetime_start
+        call grid%datetime_now%Add_seconds (grid%itimestep * grid%dt)
+        call grid%Save_state ()
+
+        write (msg, '(a, i6, a, i6, a, i6, a)') 'Isolated negative LFN cluster (size', int (global_size_value), ') near (i=', &
+            int (global_location_i), ', j=', int (global_location_j), '). Simulation stopped after saving state.'
+        call Stop_simulation (trim (msg))
+      end if
+
+    end subroutine Check_isolated_negative_lfn
+
     subroutine Prop_level_set (ifds, ifde, jfds, jfde, ifms, ifme, jfms, jfme, &
         num_tiles, i_start, i_end, j_start, j_end, ts, dt, dx, dy, fire_upwinding, fire_viscosity, &
         fire_viscosity_bg, fire_viscosity_band, fire_viscosity_ngp, fire_lsm_band_ngp, &
@@ -1667,34 +1798,25 @@ end function Select_godunov
 
     pure function Select_eno (diff_lx, diff_rx) result (return_value)
 
-      ! 1st order ENO scheme
+      ! 1st order ENO scheme: choose the smaller magnitude derivative
+      ! Both positive: pick smaller
+      ! Both negative: pick larger (less negative)
+      ! Mixed signs: zero (derivative crosses zero)
 
       implicit none
 
-      real, intent (in):: diff_lx, diff_rx
+      real, intent(in) :: diff_lx, diff_rx
       real :: return_value
 
-      real :: diff2x
 
-
-      if (.not. diff_lx > 0.0 .and. .not. diff_rx > 0.0) then
-        diff2x = diff_rx
-      else if (.not. diff_lx < 0.0 .and. .not. diff_rx < 0.0) then
-        diff2x = diff_lx
-      else if (.not. diff_lx < 0.0 .and. .not. diff_rx > 0.0) then
-        if (.not. abs (diff_rx) < abs(diff_lx)) then
-          diff2x = diff_rx
-        else
-          diff2x = diff_lx
-        end if
+      if (diff_lx * diff_rx > 0.0) then
+        return_value = sign(1.0, diff_lx) * min(abs(diff_lx), abs(diff_rx))
       else
-        diff2x = 0.0
+        return_value = 0.0
       end if
 
-      return_value = diff2x
-
     end function Select_eno
-      
+
     pure function Select_2nd (dx, lfn_i, lfn_im1, lfn_ip1) result (return_value)
 
       ! 2nd-order advection scheme in the x,y-direction (DME)

physics/ros_wrffire_mod.F90

@@ -88,15 +88,7 @@ pure function Calc_ros_wrffire (this, ifms, ifme, jfms, jfme, i, j, nvx, nvy, uf
       ros_wind = ros_wind * cor_wind
       ros_slope = ros_slope * cor_slope
 
-        ! Limit the ros
-      excess = ros_base + ros_wind + ros_slope - ROS_MAX
-      if (excess > 0.0) then
-          ! take excess out of wind and slope in proportion
-        ros_wind = ros_wind - excess * ros_wind / (ros_wind + ros_slope)
-        ros_slope = ros_slope - excess * ros_slope/ (ros_wind + ros_slope)
-      end if
-
-      return_value = ros_base + ros_wind + SLOPE_FACTOR * ros_slope
+      return_value = min (ros_base + ros_wind + SLOPE_FACTOR * ros_slope, ROS_MAX)
       if (FIRE_GROWS_ONLY) return_value = max (return_value, 0.0)
 
     end function Calc_ros_wrffire