[Mesa-users] Relaxing angle-averaged model from hydro simulation

Manos Chatzopoulos chatzopoulos at phys.lsu.edu
Tue Feb 6 18:24:38 EST 2018


Pablo,

Thanks for the very helpful and kind response! I will certainly look 
forward to trying out your suggestions. In the meantime, here is the 
terminal output I get when I include angular momentum relaxation:

-------

                        avg remaining difference, lambda 
0.0000000000000000D+00    1.0000000000000000D+00

                          relax_initial_angular_momentum
  relax_angular_momentum: max_steps_to_use        1000
failed in mixing angular momentum
        retry log10(dt/yr), log10(dt), retry_factor     1 1       
-9.602060       -2.102948        0.500000
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     2 1       
-9.903090       -2.403978        0.500000
  have reached retry limit so now backup
failed in mixing angular momentum
        retry log10(dt/yr), log10(dt), retry_factor     1 1      
-10.204120       -2.705008        0.500000
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     2 1      
-10.505150       -3.006038        0.500000
  have reached retry limit so now backup
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     1 1      
-11.408240       -3.909128        0.500000
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     2 1      
-11.709270       -4.210158        0.500000
  have reached retry limit so now backup
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     1 1      
-13.214420       -5.715308        0.500000
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     2 1      
-13.515450       -6.016338        0.500000
  have reached retry limit so now backup
                                                      dt 
3.0096197113037110D-08
                                      min_timestep_limit 
9.9999999999999995D-07

  stopping because of problems dt < min_timestep_limit

  do_relax_initial_angular_momentum ierr          -1
  do_star_job_controls_after ierr          -1
  before_evolve_loop ierr          -1


---------

And here it is when I exclude it:

  avg relative error, dt/secyer, model_number 0.73839791983438141        
4.6050354628669335E-014         712
hydro_newton_step failed to accept
        retry log10(dt/yr), log10(dt), retry_factor     1 713      
-13.938827       -6.439715        0.500000
                                                      dt 
7.2663199909396781D-07
                                      min_timestep_limit 
9.9999999999999995D-07

  stopping because of problems dt < min_timestep_limit

  do_relax_initial_entropy ierr          -1
  do_star_job_controls_after ierr          -1
  before_evolve_loop ierr          -1


--------

Cheers, and thanks again for the valuable input!

Manos




On 2/6/18 5:16 PM, Pablo Marchant wrote:
> Hi Manos,
>
> can you share your terminal output to get an idea?
>
> we are doing some work to stabilize the relax routines, can't give you 
> an ETA on that though. In particular with rotation I found that the 
> current implementation of the calculation of FP and FT (the correction 
> factors to the pressure and temperature equations) can experience some 
> large changes which make convergence hard.
>
> I have some unfinished work now trying to integrate these factors for 
> the case of a point mass Roche potential. This is a good approximation 
> for most stellar purposes, and it allows constructing a simple fit to 
> the integrated values rather than having to recompute it in MESA. 
> Attached is a simple example of this implementation, it's mostly using 
> a couple of by-eye-fits I made (see the attached plot showing the 
> factors as a function of the volume equivalent radius). Can you try 
> this out and see if it improves things at all? Goes in star/private/. 
> Not promising anything though.
>
> Another option is to increase the steps for relaxation, for instance:
>
>   num_steps_to_relax_composition = 300
>
> in star_job
>
> Cheers
>
> On Tue, Feb 6, 2018 at 4:23 PM, Manos Chatzopoulos 
> <chatzopoulos at phys.lsu.edu <mailto:chatzopoulos at phys.lsu.edu>> wrote:
>
>     Dear mesa-users,
>
>     We are using our 3D hydro code (OctoTiger) to simulate the stellar
>     merger of an 1Msun star within the envelope of a larger (~14 Msun)
>     star. We then extract the angle-averaged data in the format
>     required by the MESA (v. 10108) relaxation routines (as set in the
>     relax_composition_j_entropy test_suite setup and described in the
>     star/defaults/star_job.defaults). I attach plots of our
>     entropy_new.dat, angular_momentum_new.dat and composition_new.dat
>     inputs showing the models we import into MESA starting with the
>     inlist_relax_composition_j_entropy (attached). I also attach *png
>     plots showing comparison between these profiles (only for H/He in
>     composition) and the original profiles used in the test_suite
>     problem. As you can see we are setting the mass of the desired
>     relaxed model equal to the mass coming out from our simulation.
>
>     We are having issues getting a converged/relaxed model, especially
>     when we turn on relaxation for the angular momentum profile (Which
>     we need, ultimately). Any help/input would be greatly appreciated
>     on how to move forward.
>
>     Best regards,
>
>     -- 
>     Dr. Manos Chatzopoulos
>     Assistant Professor
>     Department of Physics & Astronomy
>     Louisiana State University
>     Nicholson #275
>     Office # 225-578-2907
>     Baton Rouge, LA 70803
>     United States of America
>     http://www.lsu.edu/physics/people/faculty/chatzopoulos.php
>     <http://www.lsu.edu/physics/people/faculty/chatzopoulos.php>
>
>
>     _______________________________________________
>     mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
>     https://lists.mesastar.org/mailman/listinfo/mesa-users
>     <https://lists.mesastar.org/mailman/listinfo/mesa-users>
>
>
>
>
>
> -- 
> Pablo Marchant Campos
> M.Sc on Astrophysics, Universidad Católica de Chile
> PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn

-- 
Dr. Manos Chatzopoulos
Assistant Professor
Department of Physics & Astronomy
Louisiana State University
Nicholson #275
Office # 225-578-2907
Baton Rouge, LA 70803
United States of America
http://www.lsu.edu/physics/people/faculty/chatzopoulos.php

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