[mesa-users] Fwd: convergence problems

[zoe ansari]

---------- Forwarded message ----------
From: Josiah Schwab <jwschwab at berkeley.edu>
Date: Tue, Jul 5, 2016 at 9:15 PM
Subject: Re: [mesa-users] convergence problems
To: zoe ansari <zoemc.ansari at gmail.com>


Please resend this message to mesa-users and not just me personally.

Josiah

On Jul 5, 2016 9:08 AM, "zoe ansari" <zoemc.ansari at gmail.com> wrote:

> Hi Josiah
>
> What I was trying to do is modifying Lane-Emden equation with adding this
> extra term i.e. (-Y/4)*(rho(r))*(G(r))*(M"(r))*(1/M'(r)) to dp/dm.
>
> I changed integer Y=6d-6 to integer, parameter:: Y=0.4 ( I wanted Y=0.4 at
> first place I just changed it to Y=6d-6 to see if it works with a lower Y)
> any way, I get all values of dp/dm which contains Y, as zero. so I just set
> Y in the expression( (Y/4) = (0.1)) and  it does kind of solve the problem
> by now.
>
> Then I changed the "rr" and determined dp/dm in 3 do-loop as you can see
> in run_star_extras.f.
>
> When I run the program without "other_momentum" subroutine it gives me
> different values for dp/dm, which contains an extra term of dp/dm of
> newtonian detemination.
>
> But when I add "other_momentum" subroutine , with new defenition for
> extra_dpdm, it does not run and gives convergence problem as you can see by
> my inlistis and run_star_extras.f in attached file.
>
>
>
> Any help would be greatly appreciated
>
> Zoe
>
>
> On Sun, Jul 3, 2016 at 10:57 PM, Josiah Schwab <jwschwab at berkeley.edu>
> wrote:
>
>> Hi Zoe,
>>
>> > I am trying to add an expression to "extra_dpdm" in other_momentum
>> > subroutine which has been added to run_star_extras.f of my work
>> > directory.
>>
>> In general, it is a good idea to briefly describe your physical
>> motivation.  For example, that lets us understand whether you need to
>> include this term during the pre-main sequence evolution of the star.
>> As indicated in the error message, MESA is struggling while constructing
>> the PMS model.
>>
>> > Here is my inlists http://www.uploadman.com/5482b953b1dbf96e or
>> >
>> http://dsa.uploadman.com/5482b953b1dbf96e?download_token=d735d3feb5bc080405aafe5c3f265a8327d5c4ea385d0ad7685f051395bf809d
>>
>> I looked at your run_star_extras.f.
>>
>> I would venture a guess that if you print the value of s% extra_dPdm
>> you'll be surprised :)
>>
>> I'll give you two hints to start.  The line
>>
>>   integer :: k, Y=6d-6
>>
>> and the lines like
>>
>>   rr= (s% r(k+1) - s% r(k))*(1/4)*(pi)*s% r(k)**2
>>
>> almost certainly don't do what you think they do.
>>
>> Why don't you try printing the values of Y and rr?
>>
>> Josiah
>>
>> P.S.  There's no need to include the full contents of your working
>> directory.  We don't need the 20 MB of executable and restart files.
>> The inlists and run_star_extras files are only a few KB.  That means you
>> will be able to directly attach them to your messages, making it even
>> easier for people to take a look.
>>
>
>
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