[Mesa-users] Relaxing a variables value between Newton-Raphson solver iterations

Francis Timmes fxt44 at mac.com
Wed Aug 31 13:47:52 UTC 2022

hi arman,

> ... may help the convergence of my star when the outer envelope is rapidly expanding.

this is not specific enough, but mesa has many options for mass loss and gain


and atmosphere boundary conditions


maybe explore some plots on how your specific model is evolving and why?


> On Aug 30, 2022, at 1:22 AM, Arman Aryaeipour via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> Dear MESA-users,
> Is there a way to relax the value of a variable for a cell, like velocity for cell 1, from an initial value to a final value between a set number of the Newton-Raphson solver iterations for every timestep?
> For example, is there a way to set v(1)=10^8 at solver_iter=1 and allow it to relax to v(1)=5x10^7 at solver_iter=5? in this scenario, I would set the minimum number of solver iterations to 10 so that the value of v(1) can converge on the correct final solution between solver iteration 6 to 10, and I would also do this for every timestep. I ask as I think this may help the convergence of my star when the outer envelope is rapidly expanding. I used the velocity variable in this example, but I am interested to know if there is a way to do this for any variable.
> I'd be grateful for any suggestions, and thank you in advance!
> Best regards,
> Arman Aryaeipour
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> mesa-users at lists.mesastar.org
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