[Mesa-users] using an index I found in another array

aldanag at campus.technion.ac.il aldanag at campus.technion.ac.il
Fri Feb 23 10:17:56 EST 2018


Thank you very much for your detailed comments. I am new with MESA and I thought the recombination energy was not included in the EOS.


Aldana.

________________________________
From: Pablo Marchant <pamarca at gmail.com>
Sent: Friday, February 23, 2018 4:41:15 PM
To: Aldana Grichener
Cc: mesa-users at lists.mesastar.org
Subject: Re: [Mesa-users] using an index I found in another array

Hi Aldana, various comments to your code snippet

         if(avg_charge_H(j) .eq. 0.5d0) then

It's almost impossible that the avg_charge will be exactly 0.5. You likely want to check for a range.

            loc=j

and because the previous if will never work, loc will never be assigned a value, it's value will just be random

               m_50_new= s% m(k .eq. loc) !s% m(loc)

Index arrays cannot be logicals, they have to be integers. The reason your code fails is because loc is never set, in your error message it is a very large negative number. That is not a valid array index, it has nothing to do with the content of s% m

               A= 1.3d13 !13.6 ev/hydrogen mass where the energy in erg/gr
               E_recomb= s% X(loc)*delta_m*A !erg
               s% extra_heat(k) = E_recomb/ s% nz !erg/g/s

This is wrong, you are computing an energy in ergs, and then dividing it by the number of zones to get the desired specific energy injection rate. That does not have the right units, and is completely resolution dependent. Even if you fix this, I'd urge you to critically evaluate the code you have written. Even if you fix the units I don't think it would do what you want.

But more importantly, why are you including the recombination energy? MESA already has this in its EOS (for clarification, see Section 8 of Paxton+2018).

Cheers

--
Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
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