[mesa-users] Question about abundances in the 1 Msun test problem

Francis Timmes fxt44 at mac.com
Wed Aug 6 23:38:28 EDT 2014

i’m not one to generate unnecessary work or endless options.
personally, i use set_uniform_xa_from_file when i want to set
an exact composition. let’s try an mini-experiment on sensing
what the community thinks would be useful.

is the current two completely general schemes and the proposed options 
for choosing between "dump missing metals in the most massive isotope” 
and "renormalize the metals” sufficient for your immediate purposes or 
is additional flexibility needed? no response means you are ok with the 
current adjustability.


On Aug 6, 2014, at 8:00 PM, Bill Paxton <paxton at kitp.ucsb.edu> wrote:

> On Aug 6, 2014, at 7:42 PM, Francis Timmes wrote:
>> how about a third option, “dump into the most abundant isotope”?
>> for this particular case, a touch more h1 may be the least perturbing solution.
> Hi Frank,
> yes, i know i did something other than what you recommended. ;D
> the reason is that it was easy to do what i did, and it is a bit harder to do 
> what you suggested given the current way the code is structured.
> it currently gets the X and Y info from the user and then picks
> a set of metal mass fractions from a given set to provide the
> remaining Z.  So transferring from Z to X or Y isn't currently
> an easy to implement option whereas changing the choice
> of metals is.    so i did the easy one first.
> i can see it now --- after adding a 3rd option to add to the most
> abundant, we'll need a 4th option that lets the user specify
> which element to use for the extra, and then 5th that says
> split the extra between H1 and He4, and then a 6th that
> says distribute the extra over all the isotopes, and then ....
> everyone should keep in mind that we already have 2
> completely general ways to see any uniform composition
> by giving the set of desired mass fractions.    one is 
> set_uniform_xa_from_file and the other is set_to_xa_for_accretion.
> so at some point we'll stop adding options and just say
> "use one of the general schemes".    but if you think it is
> important to add “dump into the most abundant isotope”
> then i'll take another look at how to do it.   you say.
> -Bill

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