[mesa-users] convergence

[Bill Paxton]

I 2nd Rob's comments.  you need to take time to understand the complexities of the implementation of mass transfer in binaries.  start by reading Pablo's excellent section in the recent MESA instrument paper (section 2).  in particular, get clear about the differences between implicit and explicit methods (section 2.3).  the implicit method adjusts mdot at each step to fine tune the radius to match the roche lobe -- it is not trying to keep mdot smooth.  instead it is trying to keep the radius close to the roche value.  try plotting the difference R minus Roche_R for comparison.

b



On May 12, 2016, at 9:48 AM, Robert Farmer wrote:

> Hi Kenney
> 
> firstly, when debugging timestep issues you should look for whats driving the timetsep. In the terminal output, look for the dt_limit (bottom right of the output)
> 
> An example from a run i've done:
> __________________________________________________________________________________________________________________________________________________
> 
>        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
> __________________________________________________________________________________________________________________________________________________
> 
> 
> 842   9.896936   3358.924   4.753581  27.226659  15.712764   9.641372   0.000000   0.000000   0.317656   0.402478   6.306150   1285     29
>   -8.132787   9.329324   3.062386  19.641098  14.283218 -99.000000   6.071392   0.010646   0.000001   0.020066   0.324405   4.490119      6     10
>  2.5759E-03  27.111358   5.183055  27.226659   2.340030  -8.721408   0.000000   0.000001   0.000000   0.000004  2.731E-01  0.000E+00   dX_nuc_drop
> 
> 
> The dX_nuc_drop is limiting my timestep, with this i can then search the controls.default to look for what controls dX_nuc_drop, which in this case is the dX_nuc_drop_limit inlist control. Tweaking that control would then alter how my timestep behaves (you may then need to do this again with another control)
> 
> 
> Secondly you may find help in:
> http://mesastar.org/teaching-materials/2015-mesa-summer-school/phinney-lecture-1-mesa-binary-and-mass-transfer-basics
> http://mesastar.org/teaching-materials/2015-mesa-summer-school/phinney-lecture-2-advanced-mass-transfer-and-binary-extras
> 
> which are lectures from the 2015 summer school on mass transfer and might help.
> 
> Rob
> 
> ------------------------------------------------------------------------------
> Mobile security can be enabling, not merely restricting. Employees who
> bring their own devices (BYOD) to work are irked by the imposition of MDM
> restrictions. Mobile Device Manager Plus allows you to control only the
> apps on BYO-devices by containerizing them, leaving personal data untouched!
> https://ad.doubleclick.net/ddm/clk/304595813;131938128;j_______________________________________________
> mesa-users mailing list
> mesa-users at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/mesa-users

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20160512/cba31b52/attachment.html>