[Developers] MoL usage: RHS for one equation is S-and-R for another?

[Jonathan Thornburg]

Hi, Ian,

Suppose I have a system of equations time-integrated with MoL

   partial_t A :=: A_rhs = fn(A,B)                   (1)
   partial_t B :=: B_rhs = fn(A_rhs,B)               (2)

Thatis, the B rhs computation uses the results of the A rhs computation.
And further suppose that we have separate thorns doing these rhs computations.

Clearly the A rhs thorn should register (A,A_rhs) as a (state-vector,rhs)
pair with MoL, and register B with MoL as S-and-R.
And the B rhs thorn should register (B,B_rhs) as a (state-vector,rhs) pair
with MoL.  But am I correct to, in the B rhs thorn, register A_rhs with
MoL as S-and-R?

(The physics example I have in mind is a Gamma-driver shift, where the
shift RHS uses partial_t of the BSSN Gamma_tildes.  Should the shift
evolution thorn really register the Gamma_tilde RHS ("source") functions
as S-and-R?)

ciao,

-- 
-- Jonathan Thornburg <jthorn at aei.mpg.de>
    Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
    Golm, Germany, "Old Europe"     http://www.aei.mpg.de/~jthorn/home.html
    "Washing one's hands of the conflict between the powerful and the
     powerless means to side with the powerful, not to be neutral."
                                       -- quote by Freire / poster by Oxfam