Thomas Bendall (tommbendall) · Mar 9, 2026 · Jul 20, 2026 · Jul 23, 2026 · Jul 24, 2026 · Jul 24, 2026
@@ -374,7 +374,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1800,
-inner_iterations=1,
+inner_iterations_si=1,1
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -29,6 +29,7 @@ module atlt_rhs_alg_mod
   use adjoint_test_parameters_mod,         only : ls_u_range, ls_theta_range,   &
                                                   ls_rho_range, ls_exner_range, &
                                                   ls_md1_range, ls_md2_range, ls_md3_range
+  use dycore_constants_mod,                only : stepper_siqn
 
   implicit none
 
@@ -208,7 +209,7 @@ module atlt_rhs_alg_mod
     ! Tangent linear
     call tl_rhs_alg( rhs, alpha_dt, base_state, state, moist_dyn, &
                      ls_state, ls_moist_dyn, compute_eos,         &
-                     dlayer_rhs, model_clock )
+                     dlayer_rhs, stepper_siqn, model_clock )
 
     ! < Mx, Mx >
     call invoke( x_innerproduct_x( base_state_inner_prod(igh_u), base_state(igh_u) ), &
@@ -312,7 +313,7 @@ module atlt_rhs_alg_mod
     ! Adjoint
     call atl_rhs_alg( rhs, alpha_dt, base_state, state, moist_dyn, &
                       ls_state, ls_moist_dyn, compute_eos,         &
-                      dlayer_rhs, model_clock )
+                      dlayer_rhs, stepper_siqn, model_clock )
 
     ! < AMx, x >
     call invoke( x_innerproduct_y( base_state_base_state_input_inner_prod(igh_u), &

@@ -23,6 +23,7 @@ module adjt_transport_controller_alg_mod
   use finite_element_config_mod,          only : element_order_h, &
                                                  element_order_v
   use fs_continuity_mod,                  only : W2, W3
+  use dycore_constants_mod,               only : stepper_siqn
   use init_from_controller_alg_mod,       only : init_ctrlr_fieldvals
   use inner_from_controller_rdef_alg_mod, only : ctrlr_ref_field_prod_rdef,         &
                                                  ctrlr_ref_field_inp_prod_rdef,     &
@@ -166,6 +167,7 @@ module adjt_transport_controller_alg_mod
     ref_field_inner_prod = 0.0_r_def
     call ls_wind_pert_rho_controller%initialise( config,           &
                                                  model_clock,      &
+                                                 stepper_siqn,     &
                                                  ref_field_rdef,   &
                                                  ls_wind_n_rdef,   &
                                                  ls_wind_np1_rdef, &
@@ -355,6 +357,7 @@ module adjt_transport_controller_alg_mod
     wind_np1_inner_prod = 0.0_r_def
     call pert_wind_ls_rho_controller%initialise( config,            &
                                                  model_clock,       &
+                                                 stepper_siqn,      &
                                                  ls_ref_field_rdef, &
                                                  wind_n_rdef,       &
                                                  wind_np1_rdef,     &
@@ -398,7 +401,7 @@ module adjt_transport_controller_alg_mod
     wn_wn_inp_inner_prod = 0.0_r_def
     wnp1_wnp1_inp_inner_prod = 0.0_r_def
     call adj_pert_wind_ls_rho_initialiser( pert_wind_ls_rho_controller, &
-                                           model_clock,                 &
+                                           model_clock, stepper_siqn,   &
                                            wind_n_rdef,                 &
                                            wind_np1_rdef )
 

@@ -11,6 +11,7 @@ module atlt_transport_control_alg_mod
   use field_mod,                           only : field_type
   use function_space_mod,                  only : function_space_type
   use constants_mod,                       only : r_def, i_def, l_def
+  use dycore_constants_mod,                only : stepper_siqn
   use log_mod,                             only : log_event,         &
                                                   log_scratch_space, &
                                                   LOG_LEVEL_INFO,    &
@@ -275,7 +276,7 @@ module atlt_transport_control_alg_mod
                                    wind_np1, wind_n, mr_out, mr_in,  &
                                    ls_advected_fields,               &
                                    ls_wind_np1, ls_wind_n, ls_mr_in, &
-                                   model_clock, outer )
+                                   model_clock, outer, stepper_siqn )
 
     ! < Mx, Mx >
     adv_inc_inner_prod = 0.0_r_def
@@ -384,7 +385,8 @@ module atlt_transport_control_alg_mod
                                     wind_np1, wind_n, mr_out, mr_in,  &
                                     ls_advected_fields,               &
                                     ls_wind_np1, ls_wind_n, ls_mr_in, &
-                                    model_clock, outer, adj_lookup_table_cache )
+                                    model_clock, outer, stepper_siqn, &
+                                    adj_lookup_table_cache )
 
     ! < AMx, x >
     ai_ai_inp_inner_prod = 0.0_r_def

@@ -9,6 +9,7 @@ module atlt_transport_controller_alg_mod
 
   use config_mod,                         only : config_type
   use constants_mod,                      only : i_def, r_def, l_def
+  use dycore_constants_mod,               only : stepper_siqn
   use field_mod,                          only : field_type
   use r_tran_field_mod,                   only : r_tran_field_type
   use log_mod,                            only : log_event,         &
@@ -197,7 +198,7 @@ module atlt_transport_controller_alg_mod
                  setval_X( wind_np1_rdef_inp, wind_np1_rdef ) )
 
     ! Initialise tl_transport_controller object
-    call tl_transport_controller%initialise( config, model_clock,               &
+    call tl_transport_controller%initialise( config, model_clock, stepper_siqn, &
                                              ref_field_rdef, ls_ref_field_rdef, &
                                              wind_n_rdef, wind_np1_rdef,        &
                                              ls_wind_n_rdef, ls_wind_np1_rdef,  &
@@ -257,6 +258,7 @@ module atlt_transport_controller_alg_mod
     rf_rf_inp_inner_prod = 0.0_r_def
     call atl_transport_controller_initialiser( tl_transport_controller, &
                                                model_clock,             &
+                                               stepper_siqn,            &
                                                ref_field_rdef,          &
                                                wind_n_rdef,             &
                                                wind_np1_rdef )

@@ -25,6 +25,7 @@ module setup_test_alg_mod
   use transport_metadata_collection_mod,   only : transport_metadata_collection
   use transport_controller_mod,            only : transport_controller_type
   use transport_counter_mod,               only : transport_counter_type
+  use dycore_constants_mod,                only : stepper_siqn
 
   implicit none
 
@@ -167,7 +168,7 @@ module setup_test_alg_mod
     outer = 1_i_def
 
     ! Initialise tl_transport_controller object
-    call tl_transport_controller%initialise( config, model_clock,               &
+    call tl_transport_controller%initialise( config, model_clock, stepper_siqn, &
                                              ref_field_rdef, ls_ref_field_rdef, &
                                              wind_n_rdef, wind_np1_rdef,        &
                                              ls_wind_n_rdef, ls_wind_np1_rdef,  &

@@ -188,7 +188,7 @@ max_tiled_multigrid_level = 1
 &timestepping
 alpha = 0.5
 dt = 100.0
-inner_iterations = 2
+inner_iterations_si = 2,2
 method = 'semi_implicit'
 outer_iterations = 2
 runge_kutta_method = 'ssp3'

@@ -284,7 +284,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=3600,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -189,7 +189,7 @@ calendar_start='2016-01-01 15:00:00',
 &timestepping
 alpha=0.5,
 dt=1000.0,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='ssp5',

@@ -205,7 +205,7 @@ calendar_start='2016-01-01 15:00:00',
 &timestepping
 alpha=0.5,
 dt=1000.0,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='ssp5',

@@ -190,7 +190,7 @@ calendar_start='2016-01-01 15:00:00',
 &timestepping
 alpha=0.5,
 dt=10.0,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='ssp5',

@@ -202,7 +202,7 @@ calendar_start='2016-01-01 15:00:00',
 &timestepping
 alpha=0.5,
 dt=10.0,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='ssp5',

@@ -357,7 +357,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1800,
-inner_iterations=1,
+inner_iterations_si=1,1
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -305,7 +305,7 @@ timestep_start='1',
 &timestepping
 alpha=0.5,
 dt=90,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -400,7 +400,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1800,
-inner_iterations=1,
+inner_iterations_si=1,1
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -399,7 +399,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1800,
-inner_iterations=1,
+inner_iterations_si=1,
 method='semi_implicit',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -342,7 +342,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=3600,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='semi_implicit',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -399,7 +399,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1800,
-inner_iterations=1,
+inner_iterations_si=1,
 method='semi_implicit',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -776,7 +776,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=600,
-inner_iterations=2,
+inner_iterations_si=2,
 method='jules',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -972,7 +972,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=1200,
-inner_iterations=2,
+inner_iterations_si=2
 method='semi_implicit',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -127,7 +127,7 @@ calendar_origin='2016-01-01 15:00:00'
 &timestepping
 alpha=0.5,
 dt=4050.0,
-inner_iterations=2,
+inner_iterations_si=2,2
 method='rk',
 outer_iterations=2,
 runge_kutta_method='forward_euler',

@@ -192,6 +192,7 @@ contains
   subroutine name_transport_step( config, model_clock, wind, tracer_con, &
                                   rho, transport_density )
 
+    use dycore_constants_mod,             only: stepper_rk
     use init_gungho_prognostics_alg_mod,  only: init_u_field
     use model_clock_mod,                  only: model_clock_type
     use sci_mass_matrix_solver_alg_mod,   only: mass_matrix_solver_alg
@@ -226,7 +227,7 @@ contains
     primary_mesh => wind%get_mesh()
 
     ! Initialise the main transport controller ---------------------------------
-    call transport_controller%initialise( config, model_clock, rho, wind )
+    call transport_controller%initialise( config, model_clock, stepper_rk, rho, wind )
 
     ! Transport dry density
     if (transport_density) then

@@ -475,7 +475,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=600,
-inner_iterations=2,
+inner_iterations_si=2,
 method='semi_implicit',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -536,7 +536,7 @@ timestep_start='1',
 &timestepping
 alpha=0.55,
 dt=600,
-inner_iterations=2,
+inner_iterations_si=2,
 method='semi_implicit',
 outer_iterations=1,
 runge_kutta_method='forward_euler',

@@ -167,7 +167,7 @@ dt                 = 0.001
         ! O(500)     for thermal double vortex test case (res 120: 486 s)
 alpha              = 0.5
 outer_iterations   = 2
-inner_iterations   = 2
+inner_iterations_si = 2,2
 runge_kutta_method = 'ssp3'
         ! This runge_kutta_method does not affect the shallow water miniapp
 spinup_alpha       = .false.

@@ -15,6 +15,7 @@ module swe_timestep_alg_mod
 
   ! Constants
   use constants_mod,                  only: i_def, r_def
+  use dycore_constants_mod,           only: stepper_siqn, stepper_rk
   use field_indices_mod,              only: isw_u, &
                                             isw_g, &
                                             isw_b, &
@@ -36,7 +37,7 @@ module swe_timestep_alg_mod
                                             tik, LPROF
   use timestepping_config_mod,        only: alpha,            &
                                             outer_iterations, &
-                                            inner_iterations
+                                            inner_iterations_si
   use transport_config_mod,           only: cheap_update
 
   ! Derived Types
@@ -486,13 +487,14 @@ contains
     outer_dynamics_loop: do outer = 1,outer_iterations
 
       ! Advect quantities
-      call swe_transport_control_alg_step( config,      &
-                                           rhs_adv,     &
-                                           adv_fields,  &
-                                           state_n,     &
-                                           state,       &
-                                           model_clock, &
-                                           outer,       &
+      call swe_transport_control_alg_step( config,       &
+                                           rhs_adv,      &
+                                           adv_fields,   &
+                                           state_n,      &
+                                           state,        &
+                                           model_clock,  &
+                                           outer,        &
+                                           stepper_siqn, &
                                            wind_prev )
 
       ! Set wind_prev to be latest estimate of wind
@@ -530,7 +532,7 @@ contains
       !============================================================================
       ! Start the inner loop
       !============================================================================
-      inner_dynamics_loop: do inner = 1,inner_iterations
+      inner_dynamics_loop: do inner = 1,inner_iterations_si(outer)
 
         ! Build residual: -R = -( rhs(state, alpha) - rhs(state_n, alpha-1) - rhs_adv)
         call swe_rhs_alg( rhs_np1, alpha_dt, state, s_geopot )
@@ -668,13 +670,14 @@ contains
     ! Advect quantities
     outer_iteration = 1_i_def
     call rhs_adv%set_scalar(0.0_r_def)
-    call swe_transport_control_alg_step( config,      &
-                                         rhs_adv,     &
-                                         adv_fields,  &
-                                         state_n,     &
-                                         state,       &
-                                         model_clock, &
-                                         outer_iteration )
+    call swe_transport_control_alg_step( config,          &
+                                         rhs_adv,         &
+                                         adv_fields,      &
+                                         state_n,         &
+                                         state,           &
+                                         model_clock,     &
+                                         outer_iteration, &
+                                         stepper_rk )
 
     ! Put RHS together
     call rhs_n%axpy(1.0_r_def, rhs_adv)