[Mesa-users] Custom screening

[Michael Famiano]

Hi All;


I'm trying to set up a custom reaction screening routine.  For my first 
attempt, I just adapted the existing screening routines (version 11701) 
and added an additional subroutine for custom screening as well as the 
option in the inlist screening_mode tag. However, I don't like the idea 
of changing the base code, so I thought the best way to do this was 
utilize the hook for other_net_get. However, I don't think I'm using the 
hook correctly.

In this case, I copied the skeleton from the other_net_get.f90 and 
modified the  null_other_net_get subroutine.  Here, I set up an array 
for the number of reactions and pointer to this array. Then, within the 
routine, I modify the screening factor for each reaction, filling the 
array I made earlier.  Then at the end of the routine, I call net_get, 
and I replace the rate_factors parameter with the pointer I made earlier.

I think I'm missing something fundamental here.  If I do something 
simple, like set the reaction factors equal to unity, the results (for 
the ns_he test, for example) match the results I would get if I disable 
screening, which is what I expect. However, if I do something like 
implement Salpeter weak screening, the results are quite different than 
if I just use the already-implemented Salpeter screening. I'm pretty 
sure the screening enhancement factors I'm using are calculated 
correctly.  (For my custom screening, I also make sure to disable 
screening in the inlist, since my routine is supposed to take care of it.)

I think I am missing something here.  Is it incorrect to use the 
other_net_get hook to do something like this, where I just pass the new 
rate factors to net_get?

I should also note that when I call net_get, I keep all the other 
parameters the same as what they were when I called null_other_net_get.

Any insight you can offer would be a great help!  Thanks a lot for your 
time!

mike