Add adaptive timestep limit for total linear JFNK iterations

mabarnes · Dec 9, 2024 · dfc7cdc · dfc7cdc
1 parent a95a8f5
commit dfc7cdc
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Showing 3 changed files with 18 additions and 10 deletions.
diff --git a/moment_kinetics/src/nonlinear_solvers.jl b/moment_kinetics/src/nonlinear_solvers.jl
@@ -71,6 +71,7 @@ struct nl_solver_info{TH,TV,Tcsg,Tlig,Tprecon,Tpretype}
     serial_solve::Bool
     max_nonlinear_iterations_this_step::Base.RefValue{mk_int}
     max_linear_iterations_this_step::Base.RefValue{mk_int}
+    total_its_soft_limit::mk_int
     preconditioner_type::Tpretype
     preconditioner_update_interval::mk_int
     preconditioners::Tprecon
@@ -98,6 +99,7 @@ function setup_nonlinear_solve(active, input_dict, coords, outer_coords=(); defa
         linear_restart=10,
         linear_max_restarts=0,
         preconditioner_update_interval=300,
+        total_its_soft_limit=50,
         adi_precon_iterations=1,
        )
 
@@ -278,7 +280,7 @@ function setup_nonlinear_solve(active, input_dict, coords, outer_coords=(); defa
                           Ref(nl_solver_input.preconditioner_update_interval),
                           Ref(mk_float(0.0)), zeros(mk_int, n_vcut_inds),
                           zeros(mk_int, n_vcut_inds), serial_solve, Ref(0), Ref(0),
-                          preconditioner_type,
+                          nl_solver_input.total_its_soft_limit, preconditioner_type,
                           nl_solver_input.preconditioner_update_interval, preconditioners)
 end
 

diff --git a/moment_kinetics/src/runge_kutta.jl b/moment_kinetics/src/runge_kutta.jl
@@ -1058,15 +1058,17 @@ end
 """
     adaptive_timestep_update_t_params!(t_params, CFL_limits, error_norms,
                                        total_points, error_norm_method, success,
-                                       nl_max_its_fraction, composition;
-                                       electron=false, local_max_dt::mk_float=Inf)
+                                       nl_max_its_fraction, nl_total_its_soft_limit,
+                                       composition; electron=false,
+                                       local_max_dt::mk_float=Inf)
 
 Use the calculated `CFL_limits` and `error_norms` to update the timestep in `t_params`.
 """
 function adaptive_timestep_update_t_params!(t_params, CFL_limits, error_norms,
                                             total_points, error_norm_method, success,
-                                            nl_max_its_fraction, composition;
-                                            electron=false, local_max_dt::mk_float=Inf)
+                                            nl_max_its_fraction, nl_total_its_soft_limit,
+                                            composition; electron=false,
+                                            local_max_dt::mk_float=Inf)
     # Get global minimum of CFL limits
     CFL_limit = Ref(0.0)
     this_limit_caused_by = nothing
@@ -1325,7 +1327,7 @@ function adaptive_timestep_update_t_params!(t_params, CFL_limits, error_norms,
                 end
             end
 
-            if nl_max_its_fraction > 0.5 && t_params.previous_dt[] > 0.0
+            if (nl_max_its_fraction > 0.5 || nl_total_its_soft_limit) && t_params.previous_dt[] > 0.0
                 # The last step took many nonlinear iterations, so do not allow the
                 # timestep to increase.
                 # If t_params.previous_dt[]==0.0, then the previous step failed so

diff --git a/moment_kinetics/src/time_advance.jl b/moment_kinetics/src/time_advance.jl
@@ -2604,7 +2604,8 @@ end
                               external_source_settings, spectral_objects,
                               advect_objects, gyroavs, num_diss_params,
                               nl_solver_params, advance, scratch_dummy, r, z, vperp,
-                              vpa, vzeta, vr, vz, success, nl_max_its_fraction)
+                              vpa, vzeta, vr, vz, success, nl_max_its_fraction,
+                              nl_total_its_soft_limit)
 
 Check the error estimate for the embedded RK method and adjust the timestep if
 appropriate.
@@ -2615,7 +2616,7 @@ appropriate.
                          geometry, external_source_settings, spectral_objects,
                          advect_objects, gyroavs, num_diss_params, nl_solver_params,
                          advance, scratch_dummy, r, z, vperp, vpa, vzeta, vr, vz, success,
-                         nl_max_its_fraction) = begin
+                         nl_max_its_fraction, nl_total_its_soft_limit) = begin
     #error_norm_method = "Linf"
     error_norm_method = "L2"
 
@@ -2925,7 +2926,7 @@ appropriate.
 
     adaptive_timestep_update_t_params!(t_params, CFL_limits, error_norms, total_points,
                                        error_norm_method, success, nl_max_its_fraction,
-                                       composition)
+                                       nl_total_its_soft_limit, composition)
 
     if composition.electron_physics ∈ (kinetic_electrons,
                                        kinetic_electrons_with_temperature_equation)
@@ -3226,6 +3227,7 @@ end
 
     if t_params.adaptive
         nl_max_its_fraction = 0.0
+        nl_total_its_soft_limit = false
         if t_params.implicit_electron_advance || t_params.implicit_electron_time_evolving
             params_to_check = (nl_solver_params.ion_advance,
                                nl_solver_params.vpa_advection,
@@ -3251,6 +3253,7 @@ end
                 nl_max_its_fraction =
                     max(p.max_nonlinear_iterations_this_step[] / p.nonlinear_max_iterations,
                         nl_max_its_fraction)
+                nl_total_its_soft_limit = p.max_linear_iterations_this_step[] > p.total_its_soft_limit || nl_total_its_soft_limit
             end
         end
         adaptive_timestep_update!(scratch, scratch_implicit, scratch_electron,
@@ -3259,7 +3262,8 @@ end
                                   geometry, external_source_settings, spectral_objects,
                                   advect_objects, gyroavs, num_diss_params,
                                   nl_solver_params, advance, scratch_dummy, r, z, vperp,
-                                  vpa, vzeta, vr, vz, success, nl_max_its_fraction)
+                                  vpa, vzeta, vr, vz, success, nl_max_its_fraction,
+                                  nl_total_its_soft_limit)
     elseif success != ""
         error("Implicit part of timestep failed")
     end