[mesa-users] delta_lgL_nuc_limit & delta_lgL_nuc_hard_limit

[Willie Strickland]

From controls.defaults starting at line 7135

      !## limits based on total integrated power at surface for all nuclear reactions
      ! excluding photodistintegrations

         ! `L_nuc` = nuclear reaction total energy release for all nuclear reactions (Lsun units)

         !### delta_lgL_nuc_limit

         ! limit for magnitude of change in `lgL_nuc`

      delta_lgL_nuc_limit = -1


         !### delta_lgL_nuc_hard_limit

         ! if max delta is greater than `delta_lgL_nuc_hard_limit`,
         ! retry with smaller timestep

      delta_lgL_nuc_hard_limit = -1


What is the reason one would use delta_lgL_nuc_limit instead of  delta_lgL_nuc_hard_limit ?
Why would one not always use delta_lgL_nuc_hard_limit ?
Does  delta_lgL_nuc_limit  stop the run ?

I notice the default for both is no-limit.

Willie



> On Thu, Mar 26, 2015 at 12:01 AM, Héctor MR <HEM52 at pitt.edu> wrote:
>   Hi,
> 
>   Thanks! Basically, this is the part of my inlist &controls section which deals with the problem:
> 
> 
>       report_why_dt_limits = .true.
>       
>       delta_lgL_nuc_limit = 0.5
>       
>       !delta_lgL_nuc_hard_limit = 0.5
>       
>       min_timestep_factor = 0.8d0
>       
>       power_nuc_burn_upper_limit = 1d15
>       
>       max_timestep =  1972350000    
>       
>       varcontrol_target = 1d-3
>       mesh_delta_coeff = 0.5
> 
>       logQ_limit = 1d6
>       gamma_center_limit = 1d6
> 
>       photostep = 50
>       profile_interval = 50
>       history_interval = 10
>       terminal_cnt = 10
>       write_header_frequency = 10
>       
>       min_timestep_limit = 1d-8 ! seconds
> 
>       T_mix_limit = 1d4
> 
> 
>   And, eventually, my terminal output shows that the variation in lg_Lnuc is bigger than the limit I established before (0.5). I do not understand my misconception regarding the command delta_lgL_nuc_limit. Lnuc is giving me problems regarding the time step and this is why I want to limit it.
> 
>   Thanks!
> 
> 
> __________________________________________________________________________________________________________________________________________________
> 
>        step    lg_Tcntr    Teff       lg_LH     lg_Lnuc     Mass       H_rich     H_cntr     N_cntr     Y_surf     X_avg     eta_cntr  zones retry
>    lg_dt_yr    lg_Dcntr    lg_R       lg_L3a    lg_Lneu     lg_Mdot    He_core    He_cntr    O_cntr     Z_surf     Y_avg     gam_cntr  iters bckup
>      age_yr    lg_Pcntr    lg_L       lg_LZ     lg_Psurf    lg_Dsurf   C_core     C_cntr     Ne_cntr    Si_cntr    Z_avg     v_div_cs     dt_limit
> __________________________________________________________________________________________________________________________________________________
> 
>         480   8.486869  2.618E+05   2.859290   3.126873   1.382237   0.000000   0.000000   0.000206   0.000000   0.000000 214.803526   1919      1
>    1.795872   9.535192  -2.586528 -29.955105   2.519596  -7.000000   0.000000   0.000000   0.618844   1.000000   0.000000  23.766144      4      0
>  3.8224E+06  27.397920   1.452514   2.789604  10.804753  -2.247950   1.382237   0.354695   0.019368   0.000662  1.000E+00 -0.519E-12        max_dt
> 
>         490   8.521023  2.618E+05   3.635027   3.909948   1.382299   0.000000   0.000000   0.000279   0.000000   0.000000 198.563837   1898      1
>    1.795872   9.535305  -2.586601 -28.919191   3.114083  -7.000000   0.000000   0.000000   0.618800   1.000000   0.000000  21.980979      4      0
>  3.8230E+06  27.398142   1.452150   3.581138  10.804681  -2.247597   1.382299   0.353850   0.019502   0.000662  1.000E+00  0.693E-12        max_dt
> 
> 
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> news, videos, case studies, tutorials and more. Take a look and join the 
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