st: global variables vs program arguments in Mata

["Zurab Sajaia" <zsajaia@hotmail.com>]

Hi all,

I'm writing program in Mata where some initial values are defined at the 
begining and then a subroutine recursively itterates on them.
Currently it looks something like:

void sub(a , b)
{
   some operations with a and b
   ...
   sub(a, b)
}

void main()
{
   a=...
   b=...
   sub(a, b)
}

So, essentially all the parameters are "globals", and I define them as 
arguments for the -sub-.
I was wondering if there was a "best" practice, in terms of efficiency, how 
should this kind of parameters defined, as externals (and use findexternal, 
createexternal functions inside the subroutine) or keep them as arguments? 
is there any gain/loss in using matrix/scalar types for the argument or I 
should use pointers as arguments?

Any thoughts would be helpful.

Thanks,
Zurab 
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