Factor timestep out of solver operators

applications/adjoint_tests/source/algorithm/lookup/solver/adjt_apply_helmholtz_op_lookup_alg_mod.x90

@@ -26,7 +26,10 @@ module adjt_apply_helmholtz_op_lookup_alg_mod
   use integer_field_mod,             only: integer_field_type
   use adj_lookup_table_mod,          only: adj_lookup_table_type
   use sci_r_solver_field_vector_mod, only: r_solver_field_vector_type
-  use si_operators_alg_mod,          only: compute_si_operators, get_helmholtz_operator
+  use si_operators_alg_mod,          only: compute_si_operators_common, &
+                                           compute_helmholtz_operators, &
+                                           get_helmholtz_operator
+  use dycore_constants_mod,          only: stepper_siqn
 
   implicit none
 
@@ -119,10 +122,11 @@ module adjt_apply_helmholtz_op_lookup_alg_mod
       call invoke(setval_random(init_op_moist_dyn(idx)))
     end do
 
-    call compute_si_operators( config, init_op_t, init_op_d, init_op_p, &
-                               model_clock, init_op_moist_dyn )
+    call compute_si_operators_common( config, init_op_t, init_op_d, init_op_p, &
+                                      init_op_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
-    Helmholtz_operator => get_helmholtz_operator(level)
+    Helmholtz_operator => get_helmholtz_operator(stepper_siqn, level)
     lam_mesh = .false.
 
     call vector_x%initialise(vector_space_w3_ptr)

applications/adjoint_tests/source/algorithm/solver/adjt_mixed_operator_alg_mod.x90

@@ -32,7 +32,9 @@ module adjt_mixed_operator_alg_mod
   use function_space_collection_mod,    only: function_space_collection
   use moist_dyn_mod,                    only: num_moist_factors
   use fs_continuity_mod,                only: W2, W3, Wtheta
-  use si_operators_alg_mod,             only: compute_si_operators
+  use si_operators_alg_mod,             only: compute_si_operators_common, &
+                                              compute_helmholtz_operators
+  use dycore_constants_mod,             only: stepper_siqn
   use sci_enforce_bc_kernel_mod,        only: enforce_bc_kernel_type
   use model_clock_mod,                  only: model_clock_type
   use function_space_mod,               only: function_space_type
@@ -115,8 +117,9 @@ contains
       call invoke(setval_random(moist_dyn(idx)))
     end do
 
-    call compute_si_operators( config, rhs(igh_t), rhs(igh_d), rhs(igh_p), &
-                               model_clock, moist_dyn )
+    call compute_si_operators_common( config, rhs(igh_t), rhs(igh_d), rhs(igh_p), &
+                                      moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
     ! Input fields are r_def fields so preliminary work uses field_types
 
@@ -144,7 +147,7 @@ contains
     call construct_solver_state( vector_mx, rhs_rsol, import_fields=.false. )
     call construct_solver_state( vector_amx, rhs_rsol, import_fields=.false. )
 
-    mixed_op = mixed_operator_type()
+    mixed_op = mixed_operator_type(stepper_siqn)
 
     call vector_mx%set_scalar(0.0_r_def)
     call vector_amx%set_scalar(0.0_r_def)
@@ -184,7 +187,7 @@ contains
     ! Adjoint code
     ! --------------------------------------------------------------------------
 
-    adj_mixed_op = adj_mixed_operator_type()
+    adj_mixed_op = adj_mixed_operator_type(stepper_siqn)
 
     call adj_mixed_op%apply( vector_mx, vector_amx )
 

applications/adjoint_tests/source/algorithm/solver/adjt_mixed_schur_preconditioner_alg_mod.x90

@@ -29,7 +29,9 @@ module adjt_mixed_schur_preconditioner_alg_mod
   use function_space_collection_mod,    only: function_space_collection
   use driver_modeldb_mod,               only: modeldb_type
   use fs_continuity_mod,                only: W2, W3, Wtheta
-  use si_operators_alg_mod,             only: compute_si_operators
+  use si_operators_alg_mod,             only: compute_si_operators_common, &
+                                              compute_helmholtz_operators
+  use dycore_constants_mod,             only: stepper_siqn
   use sci_enforce_bc_kernel_mod,        only: enforce_bc_kernel_type
   use model_clock_mod,                  only: model_clock_type
   use function_space_mod,               only: function_space_type
@@ -160,17 +162,19 @@ contains
     call moisture_fields%get_field( "ls_moist_dyn", ls_moist_dyn_array )
     ls_moist_dyn => ls_moist_dyn_array%bundle
 
-    call compute_si_operators( modeldb%config, ls_theta, ls_rho, ls_exner, &
-                               model_clock, ls_moist_dyn )
+    call compute_si_operators_common( modeldb%config, ls_theta, ls_rho, ls_exner, &
+                                      ls_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
-    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner )
+    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner, stepper_siqn )
     call create_pressure_solver( pressure_operator, pressure_preconditioner, pressure_solver )
-    call create_mixed_preconditioner( rhs, pressure_solver, mixed_preconditioner )
+    call create_mixed_preconditioner( rhs, pressure_solver, mixed_preconditioner, stepper_siqn )
 
     call create_adj_pressure_preconditioner( rhs, adj_lookup_table_cache, &
-                                             adj_pressure_operator, adj_pressure_preconditioner )
+                                             adj_pressure_operator, adj_pressure_preconditioner, &
+                                             stepper_siqn )
     call create_adj_pressure_solver( adj_pressure_operator, adj_pressure_preconditioner, adj_pressure_solver )
-    call create_adj_mixed_preconditioner( rhs, adj_pressure_solver, adj_mixed_preconditioner )
+    call create_adj_mixed_preconditioner( rhs, adj_pressure_solver, adj_mixed_preconditioner, stepper_siqn )
 
     call construct_solver_state( vector_x, rhs_rsol, import_fields=.true. )
     call construct_solver_state( vector_mx, rhs_rsol, import_fields=.false. )

applications/adjoint_tests/source/algorithm/solver/adjt_mixed_solver_alg_mod.x90

@@ -34,7 +34,9 @@ module adjt_mixed_solver_alg_mod
   use driver_modeldb_mod,               only: modeldb_type
   use solver_constants_mod,             only: get_normalisation
   use fs_continuity_mod,                only: W2, W3, Wtheta
-  use si_operators_alg_mod,             only: compute_si_operators
+  use si_operators_alg_mod,             only: compute_si_operators_common, &
+                                              compute_helmholtz_operators
+  use dycore_constants_mod,             only: stepper_siqn
   use operator_mod,                     only: operator_type
   use sci_enforce_bc_kernel_mod,        only: enforce_bc_kernel_type
   use model_clock_mod,                  only: model_clock_type
@@ -189,19 +191,21 @@ contains
     call moisture_fields%get_field( "ls_moist_dyn", ls_moist_dyn_array )
     ls_moist_dyn => ls_moist_dyn_array%bundle
 
-    call compute_si_operators( modeldb%config, ls_theta, ls_rho, ls_exner, &
-                               model_clock, ls_moist_dyn )
+    call compute_si_operators_common( modeldb%config, ls_theta, ls_rho, ls_exner, &
+                                      ls_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
-    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner )
+    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner, stepper_siqn )
     call create_pressure_solver( pressure_operator, pressure_preconditioner, pressure_solver )
-    call create_mixed_preconditioner( rhs, pressure_solver, mixed_preconditioner )
-    call create_mixed_solver( mixed_preconditioner, mixed_operator, mixed_solver )
+    call create_mixed_preconditioner( rhs, pressure_solver, mixed_preconditioner, stepper_siqn )
+    call create_mixed_solver( mixed_preconditioner, mixed_operator, mixed_solver, stepper_siqn )
 
     call create_adj_pressure_preconditioner( rhs, adj_lookup_table_cache, &
-                                             adj_pressure_operator, adj_pressure_preconditioner )
+                                             adj_pressure_operator, adj_pressure_preconditioner, &
+                                             stepper_siqn )
     call create_adj_pressure_solver( adj_pressure_operator, adj_pressure_preconditioner, adj_pressure_solver )
-    call create_adj_mixed_preconditioner( rhs, adj_pressure_solver, adj_mixed_preconditioner )
-    call create_adj_mixed_solver( adj_mixed_preconditioner, adj_mixed_operator, adj_mixed_solver )
+    call create_adj_mixed_preconditioner( rhs, adj_pressure_solver, adj_mixed_preconditioner, stepper_siqn )
+    call create_adj_mixed_solver( adj_mixed_preconditioner, adj_mixed_operator, adj_mixed_solver, stepper_siqn )
 
     call construct_solver_state( vector_x, rhs_rsol, import_fields=.true. )
     call construct_solver_state( vector_mx, rhs_rsol, import_fields=.false. )

applications/adjoint_tests/source/algorithm/solver/adjt_pressure_precon_alg_mod.x90

@@ -27,7 +27,9 @@ module adjt_pressure_precon_alg_mod
   use function_space_collection_mod,    only: function_space_collection
   use driver_modeldb_mod,               only: modeldb_type
   use fs_continuity_mod,                only: W2, W3, Wtheta
-  use si_operators_alg_mod,             only: compute_si_operators
+  use si_operators_alg_mod,             only: compute_si_operators_common, &
+                                              compute_helmholtz_operators
+  use dycore_constants_mod,             only: stepper_siqn
   use sci_enforce_bc_kernel_mod,        only: enforce_bc_kernel_type
   use model_clock_mod,                  only: model_clock_type
   use function_space_mod,               only: function_space_type
@@ -149,15 +151,17 @@ contains
     call moisture_fields%get_field( "ls_moist_dyn", ls_moist_dyn_array )
     ls_moist_dyn => ls_moist_dyn_array%bundle
 
-    call compute_si_operators( modeldb%config, ls_theta, ls_rho, ls_exner, &
-                               model_clock, ls_moist_dyn )
+    call compute_si_operators_common( modeldb%config, ls_theta, ls_rho, ls_exner, &
+                                      ls_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
-    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner )
+    call create_pressure_preconditioner( rhs, pressure_operator, pressure_preconditioner, stepper_siqn )
 
-    call create_adj_pressure_preconditioner( rhs,                    &
-                                             adj_lookup_table_cache, &
-                                             adj_pressure_operator,  &
-                                             adj_pressure_preconditioner )
+    call create_adj_pressure_preconditioner( rhs,                         &
+                                             adj_lookup_table_cache,      &
+                                             adj_pressure_operator,       &
+                                             adj_pressure_preconditioner, &
+                                             stepper_siqn )
 
     ! Size = 1 as only P field needed
     vector_x = r_solver_field_vector_type(1_i_def)

applications/adjoint_tests/source/algorithm/solver/adjt_scaled_matrix_vector_alg_mod.x90

@@ -2,6 +2,9 @@
 ! (C) Crown copyright 2025 Met Office. All rights reserved.
 ! The file LICENCE, distributed with this code, contains details of the terms
 ! under which the code may be used.
+!
+! Some of the content of this file has been produced with the assistance of
+! Met Office GitHub Copilot Enterprise.
 !-----------------------------------------------------------------------------
 
 ! @todo Causes failure of later test (mixed_schur_preconditioner); not calling until resolved (#616).
@@ -23,7 +26,11 @@ module adjt_scaled_matrix_vector_alg_mod
   use operator_mod,                  only: r_solver_operator_type
   use r_solver_field_mod,            only: r_solver_field_type
   use sci_r_solver_field_vector_mod, only: r_solver_field_vector_type
-  use si_operators_alg_mod,          only: compute_si_operators, get_div_star, get_Hb_lumped_inv
+  use si_operators_alg_mod,          only: compute_si_operators_common, &
+                                           compute_helmholtz_operators, &
+                                           get_div_star, get_Hb_lumped_inv, &
+                                           get_tau_u_dt_cp
+  use dycore_constants_mod,          only: stepper_siqn
   use solver_constants_mod,          only: get_normalisation_r_solver
 
   ! Object types
@@ -83,6 +90,7 @@ module adjt_scaled_matrix_vector_alg_mod
     real(kind=r_def)            :: machine_tolerance
     real(kind=r_def)            :: relative_diff
     real(kind=r_def), parameter :: overall_tolerance = 1500.0_r_def
+    real(kind=r_solver)         :: const_u
 
     ! Setup
 
@@ -106,24 +114,28 @@ module adjt_scaled_matrix_vector_alg_mod
       call invoke(setval_random(init_op_moist_dyn(idx)))
     end do
 
-    call compute_si_operators( config, init_op_t, init_op_d, init_op_p, &
-                               model_clock, init_op_moist_dyn )
+    call compute_si_operators_common( config, init_op_t, init_op_d, init_op_p, &
+                                      init_op_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
 
     call vector_x%initialise(vector_space_w3_ptr)
     call vector_mx%initialise(vector_space_w2_ptr)
     call vector_x%copy_field_properties(vector_amx)
 
     u_normalisation => get_normalisation_r_solver( W2, vector_mx%get_mesh_id() )
     div_star        => get_div_star()
-    Hb_lumped_inv   => get_Hb_lumped_inv()
+    Hb_lumped_inv   => get_Hb_lumped_inv(stepper_siqn)
+
+    const_u = get_tau_u_dt_cp(stepper_siqn)
 
     call invoke( setval_random(vector_x),                                                                           &
                  setval_c( vector_mx, 0.0_r_solver ),                                                               &
                  setval_c( vector_amx, 0.0_r_solver ),                                                              &
 
     ! Tangent linear (Mx)
 
-                 scaled_matrix_vector_kernel_type( vector_mx, vector_x, div_star, u_normalisation, Hb_lumped_inv ), &
+                 scaled_matrix_vector_kernel_type( vector_mx, vector_x, div_star, u_normalisation, Hb_lumped_inv, &
+                                                   const_u ),                                                        &
 
     ! <Mx,Mx>
 
@@ -143,7 +155,8 @@ module adjt_scaled_matrix_vector_alg_mod
 
     ! Adjoint (AMx)
 
-                 adj_scaled_matrix_vector_kernel_type( vector_mx, vector_amx, div_star, u_normalisation, Hb_lumped_inv ), &
+                 adj_scaled_matrix_vector_kernel_type( vector_mx, vector_amx, div_star, u_normalisation,          &
+                                                       Hb_lumped_inv, const_u ),                                   &
 
     ! <AMx,x>
 

applications/adjoint_tests/source/algorithm/solver/adjt_semi_implicit_solver_step_alg_mod.x90

@@ -28,7 +28,9 @@ module adjt_semi_implicit_solver_step_alg_mod
   use driver_modeldb_mod,               only: modeldb_type
   use fs_continuity_mod,                only: W2, W3, Wtheta
   use mr_indices_mod,                   only: nummr
-  use si_operators_alg_mod,             only: compute_si_operators
+  use si_operators_alg_mod,             only: compute_si_operators_common, &
+                                              compute_helmholtz_operators
+  use dycore_constants_mod,             only: stepper_siqn
   use operator_mod,                     only: operator_type
   use sci_enforce_bc_kernel_mod,        only: enforce_bc_kernel_type
   use model_clock_mod,                  only: model_clock_type
@@ -163,9 +165,10 @@ contains
     call moisture_fields%get_field( "ls_moist_dyn", ls_moist_dyn_array )
     ls_moist_dyn => ls_moist_dyn_array%bundle
 
-    call compute_si_operators( modeldb%config, ls_theta, ls_rho, ls_exner, &
-                               model_clock, ls_moist_dyn )
-    call adj_semi_implicit_solver%initialise(rhs, adj_lookup_table_cache)
+    call compute_si_operators_common( modeldb%config, ls_theta, ls_rho, ls_exner, &
+                                      ls_moist_dyn )
+    call compute_helmholtz_operators( model_clock, stepper_siqn )
+    call adj_semi_implicit_solver%initialise(rhs, adj_lookup_table_cache, stepper_siqn)
 
     ! Set up moist_dyn_gas_law & mr
     call moist_dyn_gas_law%initialise(vector_space=vector_space_wtheta_ptr)
@@ -288,7 +291,7 @@ contains
     ! --------------------------------------------------------------------------
 
     call semi_implicit_solver_alg_step( state, rhs, dry_flux_solver, &
-                                        moist_dyn_gas_law, mr, first_iteration )
+                                        moist_dyn_gas_law, mr, first_iteration, stepper_siqn )
 
     ! --------------------------------------------------------------------------
     ! Compute <Mx,Mx>

applications/adjoint_tests/source/algorithm/timestepping/atlt_si_timestep_alg_mod.x90

@@ -35,7 +35,9 @@ module atlt_si_timestep_alg_mod
                                                      tl_semi_implicit_alg_final
   use atl_si_timestep_alg_mod,                 only: atl_si_timestep_type
   use driver_modeldb_mod,                      only: modeldb_type
-  use si_operators_alg_mod,                    only: compute_si_operators
+  use si_operators_alg_mod,                    only: compute_si_operators_common, &
+                                                     compute_helmholtz_operators
+  use dycore_constants_mod,                    only: stepper_siqn
   use sci_enforce_bc_kernel_mod,               only: enforce_bc_kernel_type
   use field_array_mod,                         only: field_array_type
 
@@ -185,10 +187,11 @@ contains
 
     call tl_semi_implicit_alg_init( mesh, u, rho, theta, exner, mr,   &
                                     ls_u, ls_rho, ls_theta, ls_exner, &
-                                    ls_mr, ls_moist_dyn, (num_steps == 1) )
+                                    ls_mr, ls_moist_dyn, modeldb, (num_steps == 1) )
 
-    call compute_si_operators( modeldb%config, ls_theta, ls_rho, ls_exner, &
-                               modeldb%clock, ls_moist_dyn )
+    call compute_si_operators_common( modeldb%config, ls_theta, ls_rho, ls_exner, &
+                                      ls_moist_dyn )
+    call compute_helmholtz_operators( modeldb%clock, stepper_siqn )
 
     do i = 1, num_steps
       call tl_semi_implicit_alg_step( modeldb, u, rho, theta, exner, mr, moist_dyn,          &

dependencies.yaml

@@ -30,8 +30,8 @@ lfric_apps:
     ref:
 
 lfric_core:
-   source: git@github.com:MetOffice/lfric_core.git
-   ref: 2026.07.1
+   source: git@github.com:tommbendall/lfric_core.git
+   ref: 932de2756a609a4982ce34feb3f1911e0a2ee617
 
 moci:
     source: git@github.com:MetOffice/moci.git

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_agnesi_hyd_cart-BiP120x8-2000x2000_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 40DAA271B7D2549D
-Inner product checksum theta = 42418E8247B61657
-Inner product checksum u = 43F0A73C1317F206
+Inner product checksum rho = 40DAA271B7D254AF
+Inner product checksum theta = 42418E8247B61632
+Inner product checksum u = 43F0A73C1317F297

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-C24_MG_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 40E2F2B22471284D
-Inner product checksum theta = 4210411A3413C5A2
-Inner product checksum u = 4501AC432273CA03
+Inner product checksum rho = 40E2F2B224494971
+Inner product checksum theta = 4210411A341A1A2D
+Inner product checksum u = 4501AC43210280BA

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-C48_MG-2panel_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 4102EEF5FAAF36AB
-Inner product checksum theta = 423041DD8254B694
-Inner product checksum u = 45017CE3BDCC7471
+Inner product checksum rho = 4102EEF5FA87CBE1
+Inner product checksum theta = 423041DD825A8404
+Inner product checksum u = 45017CE3BA63F0FA

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-C48_MG-3panel_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 4102EEF5FAAF36A3
-Inner product checksum theta = 423041DD8254B695
-Inner product checksum u = 45017CE3BDCC746C
+Inner product checksum rho = 4102EEF5FA87CBE2
+Inner product checksum theta = 423041DD825A8403
+Inner product checksum u = 45017CE3BA63F106

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-C48_MG_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 4102EEF5FAAF36AA
-Inner product checksum theta = 423041DD8254B693
-Inner product checksum u = 45017CE3BDCC746C
+Inner product checksum rho = 4102EEF5FA87CBE0
+Inner product checksum theta = 423041DD825A8404
+Inner product checksum u = 45017CE3BA63F10A

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-alt1-C24s_MG_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 40E31B89B4F18C5A
-Inner product checksum theta = 42104617DFB2BB0E
-Inner product checksum u = 4500F65BA3091AE0
+Inner product checksum rho = 40E31B568E5A4E4A
+Inner product checksum theta = 4210461E78734A26
+Inner product checksum u = 4500F54C439B1A5A

rose-stem/site/meto/kgos/gungho_model/azspice/checksum_gungho_model_baroclinic-alt2-C24_MG_op_azspice_gnu_fast-debug-64bit.txt

@@ -1,3 +1,3 @@
-Inner product checksum rho = 40E2EB31AE9BB095
-Inner product checksum theta = 42104262EDD0C3CB
-Inner product checksum u = 4501DA5CB7431A79
+Inner product checksum rho = 40E2EB31AEBFEF72
+Inner product checksum theta = 42104262EDD13B2E
+Inner product checksum u = 4501DA5CAEFE8D62