[mesa-users] trace the computational cell that is limiting the timestep

Sun Apr 13 10:46:11 EDT 2014

Hi everyone,

I am wondering if there is a way to trace which computational cell is 
limiting the timestep in MESA 6208.

I am trying to simulate a 15 solar mass star with MESA 6208 and I find 
extremely small timesteps during Si shell burning.
I know I could lower the min_timestep_limit (setting it to 10^-10 sec 
the run goes on), but I'd like to find why and where such small 
timesteps are needed.
I attach the inlist I am using and a photo (284000), if someone wants to 
reproduce the problem.

Thanks for any suggestion,

Mathieu

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! inlist_project 

! contains the parameters controlling this job

! for the sake of future readers of this (yourself included),
! ONLY include the controls you are actually using.
! DO NOT include all of the other controls that
! simply have their default values.

!This inlist has been created merging "inlist_massive_defaults" and "inlist_massive_15M_z1.9m2"

&star_job

      mesa_dir = '' ! empty string defaults to environment variable MESA_DIR

      show_log_description_at_start = .true.

      create_pre_main_sequence_model = .true.

      change_net = .true.      
      new_net_name = 'approx26.net'  

      set_rates_preference = .true. ! for use by net + rates modules
      new_rates_preference = 2 ! only used if set_rates_preference is true
      ! 1 = NACRE rates -- this is the default
      ! 2 = jina reaclib rates

      T_lo_neut = 2d9	
      T_hi_neut= 5d9
      min_factor_neut = 1d-9

      T_lo_prot = 2d9
      T_hi_prot = 5d9
      min_factor_prot = 1d-12

      ! rate limit factors for high temperatures
      turn_on_T_limits = .true.
      turn_off_T_limits = .false.

      eos_file_prefix = 'mesa'
      kappa_file_prefix = 'gs98'

      set_initial_age = .true.
      initial_age = 0 ! in years

      set_initial_model_number = .true.
      initial_model_number = 0

      save_photo_when_terminate = .true.
      pause_before_terminate = .false.
      pgstar_flag = .false.

/ !end of star_job

&controls

  ! starting specifications
      initial_mass = 15 ! in Msun units
      !solar chemical composition
      initial_Z = 0.019
      initial_Y = 0.27

   !min_T_for_time_averaged_conv_velocity = 3e9

   ! high center T limit to avoid negative mass fractions
   sig_min_factor_for_high_Tcenter = 0.01
   ! inactive when >= 1d0
   ! if Tcenter >= Tcenter_min_for_sig_min_factor_full_on,
   ! then okay to reduce sig by as much as this factor
   ! as needed to prevent causing negative abundances
   Tcenter_min_for_sig_min_factor_full_on = 2d9
   ! if Tcenter >= this, factor = sig_min_factor_for_neg_abundances
   ! this should be > Tcenter_max_for_sig_min_factor_full_off.
   Tcenter_max_for_sig_min_factor_full_off = 1d9
   ! if Tcenter <= this, factor = 1, so has no effect
   ! this should be < Tcenter_min_for_sig_min_factor_full_on.
   ! for T > full_off and < full_on, factor changes linearly with Tcenter

   min_years_dt_for_redo_mdot = 1 ! experimental

   num_trace_history_values = 0
   trace_history_value_name(1) = 'surf_avg_v_div_v_crit'

   ! output to files and terminal
      photostep = 50
      profile_interval = 10
      history_interval = 1
      terminal_interval = 10
      write_header_frequency = 10

  velocity_logT_lower_bound = 8
         max_dt_yrs_for_velocity_logT_lower_bound = 0.1

         mesh_delta_coeff = 1.5
         mesh_delta_coeff_for_highT = 2.5
         logT_max_for_standard_mesh_delta_coeff = 9.0 
         logT_min_for_highT_mesh_delta_coeff = 9.5 

         dX_nuc_drop_limit = 7d-3
         delta_Ye_highT_limit = 1d-4

         okay_to_reduce_gradT_excess = .true. 

            gradT_excess_f1 = 1d-4
            gradT_excess_f2 = 1d-2
            gradT_excess_age_fraction = 0.9d0

            gradT_excess_lambda1 = 1.0
            gradT_excess_beta1 = 0.35

            gradT_excess_lambda2 = 0.5
            gradT_excess_beta2 = 0.25

            gradT_excess_dlambda = 0.1
            gradT_excess_dbeta = 0.1

      !Mass Loss
         RGB_wind_scheme = 'Nieuwenhuijzen'
         AGB_wind_scheme = 'Nieuwenhuijzen'
         RGB_to_AGB_wind_switch = 1d-4
         Nieuwenhuijzen_wind_eta = 0.0

         use_Type2_opacities = .true.
         Zbase = 0.02

         xa_scale = 1d-5
         newton_itermin = 2

         mixing_length_alpha = 1.0
	 MLT_option = 'Henyey'

         use_Ledoux_criterion = .true.
         alpha_semiconvection = 0.1
!         thermo_haline_coeff = 2
!         thermohaline_option = 'Kippenhahn'

         overshoot_f_above_nonburn = 0.01
         overshoot_f_above_burn_h = 0.01
         overshoot_f_above_burn_he = 0.01
         overshoot_f_above_burn_z = 0.01
         overshoot_f_below_nonburn = 0.01
         overshoot_f_below_burn_h = 0.01
         overshoot_f_below_burn_he = 0.01
         overshoot_f_below_burn_z = 0.01

         set_min_D_mix = .true.
         min_D_mix = 1d3 ! D_mix will be at least this large
         min_center_Ye_for_min_D_mix = 0

         screening_mode = 'extended'

         max_iter_for_resid_tol1 = 3
         tol_residual_norm1 = 1d-5
         tol_max_residual1 = 1d-2

         max_iter_for_resid_tol2 = 12
         tol_residual_norm2 = 1d99
         tol_max_residual2 = 1d99

         min_timestep_limit = 1d-12 ! (seconds)

         delta_lgL_He_limit = 0.1 ! limit for magnitude of change in lgL_He

         dX_nuc_drop_max_A_limit = 52
         dX_nuc_drop_min_X_limit = 1d-4
         dX_nuc_drop_hard_limit = 1d99

         delta_lgTeff_limit = 0.5  
         delta_lgL_limit = 0.5
         delta_lgRho_cntr_limit = 0.02  

!         mesh_dlog_pp_dlogP_extra = 0.4
!         mesh_dlog_cno_dlogP_extra = 0.4
!      
!         mesh_dlog_burn_n_dlogP_extra = 0.4
!         mesh_dlog_3alf_dlogP_extra = 0.4
!         mesh_dlog_burn_c_dlogP_extra = 0.4

          xa_function_species(1) = 'h1'
	  xa_function_weight(1) = 70
          xa_function_param(1) = 1d-3

	  xa_function_species(2) = 'he4'
	  xa_function_weight(2) = 70
  	  xa_function_param(2) = 1d-3

         T_mix_limit = 0

         varcontrol_target = 1d-4
         mesh_delta_coeff=1
!	 mesh_max_allowed_ratio=15
         min_timestep_limit = 1d-6 !in sec
         ! when to stop
           fe_core_infall_limit = 1d8  
/

&pgstar        
      ! top level controls
        ! pause = .true. 
            ! if true, the code waits for user to enter a RETURN on the command line

      ! main window

         MAIN_win_flag = .true.

         show_TRho_Profile_with_main = .true.

         show_HR_TRho_with_main = .true. ! if false, use aspect ratio > 1
         MAIN_win_width = 7
         MAIN_win_aspect_ratio = 1.2 ! aspect_ratio = height/width

         xaxis_by = 'by_mass' !'by_radius' 

         show_main_win_text_info = .true.

         ! xaxis limits -- to override system default selections
         !main_xmin = -12 !0.4
         !main_xmax = 4.5

         logxq_cutoff = -12.1 ! min value when using logxm for xaxis
         !main_logL_max = 7
         !main_logL_min = 0

         ! control for plot showing abundances
         log_mass_frac_ymax = 0.7 ! making this > 0 helps readability
         log_mass_frac_ymin = -7.5
         num_abundance_line_labels = 5

         log_abund_vary = 0.1 ! don't show species if it would vary by < this in plot

         ! file output
         !MAIN_file_flag = .true.
         MAIN_file_dir = 'png'
         MAIN_file_prefix = 'main'
         MAIN_file_cnt = 1 ! output when mod(model_number,main_file_cnt)==0

      ! Abund_TRho_History window -- Abundance and Center TRho History together

         Abund_TRho_History_win_flag = .true.

         Abund_TRho_History_win_width = 7.0
         Abund_TRho_History_win_aspect_ratio = 1.2 ! aspect_ratio = height/width

         Abund_TRho_History_xaxis_by = 'by_mass' ! select xaxis (same options as for main window)
            ! not used if == ''
         Abund_TRho_History_xmin = -101 ! only used if > -100
         Abund_TRho_History_xmax = 5 ! only used if > -100

         ! file output
         !Abund_TRho_History_file_flag = .true.
         Abund_TRho_History_file_dir = 'png'
         Abund_TRho_History_file_prefix = 'abund_trho_history'
         Abund_TRho_History_file_cnt = 3 ! output when mod(model_number,Abund_TRho_History_file_cnt)==0
         Abund_TRho_History_file_width = -1 ! negative means use same value as for window
         Abund_TRho_History_file_aspect_ratio = -1 ! negative means use same value as for window

      ! Mixing_Dynamo window -- Mixing_Ds and Dynamo together

         Mixing_Dynamo_win_flag = .false.

         Mixing_Dynamo_win_width = 7
         Mixing_Dynamo_win_aspect_ratio = 1.2 ! aspect_ratio = height/width

         Mixing_Dynamo_xaxis_by = '' ! select xaxis (same options as for main window)
            ! not used if == ''
         Mixing_Dynamo_xmin = -101 ! only used if > -100
         Mixing_Dynamo_xmax = -101 ! only used if > -100

         ! file output
         Mixing_Dynamo_file_flag = .false.
         Mixing_Dynamo_file_dir = 'pgstar_out'
         Mixing_Dynamo_file_prefix = 'md'
         Mixing_Dynamo_file_cnt = 5 ! output when mod(model_number,Mixing_Dynamo_file_cnt)==0
         Mixing_Dynamo_file_width = -1 ! negative means use same value as for window
         Mixing_Dynamo_file_aspect_ratio = -1 ! negative means use same value as for window

/ ! end of pgstar namelist