[Mesa-users] Follow-up on Modifying Double_BH Test Suite in MESA: Switching Accretor and Donor

[Levi]

Dear MESA-users group,



I am writing to provide further details on the modifications I made to the double_bh test suite in MESA version 24.03.1, specifically in the run_binary_extras.f90 file, as mentioned in my previous email. I have attached the complete code in a compressed file for your reference.


Here is the additional code I implemented in the extras_binary_finish_step(binary_id) subroutine:
if (b% rl_relative_gap(b% d_i) > -0.05 .and. b% rl_relative_gap(b% a_i) > -0.05) then  
    write(*,*) "rl_relative_gap(b% a_i)", b% rl_relative_gap(b% a_i)  
    write(*,*) "s_accretor% w_div_w_crit_avg_surf", b% s_accretor% w_div_w_crit_avg_surf  
    if (b% s_accretor% w_div_w_crit_avg_surf > 0.95 .and. b% s_donor% w_div_w_crit_avg_surf < 0.95) then  
       switch_donor = .true.  
    else if (b% s_donor% w_div_w_crit_avg_surf > 0.95 .and. b% s_accretor% w_div_w_crit_avg_surf > 0.95) then  
       extras_binary_finish_step = terminate  
    end if  
end if  
  
if (switch_donor) then  
    write(*,*) "switching donor"  
    if (b% d_i == 2) then  
       b% d_i = 1  
       b% a_i = 2  
       b% s_donor => b% s1  
       b% s_accretor => b% s2  
    else  
       b% d_i = 2  
       b% a_i = 1  
       b% s_donor => b% s2  
       b% s_accretor => b% s1  
    end if  
end if
Upon running the simulation with these modifications, I encountered an error related to accretion species mass fractions not adding up to 1.0. I have included the terminal output in the attached file rn.out for your reference.


I would greatly appreciate any insights into what might be causing this error and how I could resolve it. Additionally, if there are any suggestions or best practices for modifying the MESA code to switch accretor and donor stars based on specific conditions, I would be very thankful to hear them.


Thank you very much for your time and assistance. I look forward to your response.


Best regards,
Levi




---- Replied Message ----
| From | Levi via Mesa-users<mesa-users at lists.mesastar.org> |
| Date | 7/17/2024 19:49 |
| To | mesa-users at lists.mesast…<mesa-users at lists.mesastar.org> |
| Subject | [Mesa-users] Issues with modifying double_bh test suite to switch accretor and donor |
Dear MESA-users group,



I am currently using MESA version 24.03.1 and have been attempting to modify the double_bh test suite to switch the accretor and donor stars based on certain conditions. To achieve this, I added the following code to the run_binary_extras.f90 file:
if (b% rl_relative_gap(b% d_i) > -0.05 .and. b% rl_relative_gap(b% a_i) > -0.05) then      write(*,*) "rl_relative_gap(b% a_i)", b% rl_relative_gap(b% a_i)      write(*,*) "s_accretor% w_div_w_crit_avg_surf", b% s_accretor% w_div_w_crit_avg_surf      if (b% s_accretor% w_div_w_crit_avg_surf > 0.95 .and. b% s_donor% w_div_w_crit_avg_surf < 0.95) then         switch_donor = .true.      else if (b% s_donor% w_div_w_crit_avg_surf > 0.95 .and. b% s_accretor% w_div_w_crit_avg_surf > 0.95) then         extras_binary_finish_step = terminate    end if   end if  
However, upon running the simulation, I encountered the following error:
get_xa_for_accretion: accretion species mass fractions do not add to 1.0                                       sum(xa(1:species))    0.0000000000000000D+00                                                       h1           1    0.0000000000000000D+00                                                      he3           2    0.0000000000000000D+00                                                      he4           3    0.0000000000000000D+00                                                      c12           4    0.0000000000000000D+00                                                      n14           5    0.0000000000000000D+00                                                      o16           6    0.0000000000000000D+00                                                     ne20           7    0.0000000000000000D+00                                                     mg24           8    0.0000000000000000D+00   retry: get_xa_for_accretion failed in adjust mass     176   retry: get_xa_for_accretion failed in adjust mass     176
I am unsure what might be causing this issue, and I have attached the terminal output in the file rn.out for your reference.
Could anyone please provide some insight into what might be causing this error and how I might resolve it?
Thank you very much for your time and assistance.


Best regards,
Levi



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