[FLASH-USERS] Custom Region code (was: FLASH 4.0 released)

[Klaus Weide]

On Wed, 19 Sep 2012, Morgan MacLeod wrote:

> Dear FLASH Users,
> 
> I noticed that the option to excise a hole from the grid with the split
> solver appears to have been removed between FLASH4-beta and FLASH4. (this
> used to be done with useHole = .true.).
> 
> Can anyone comment on the reason for removing this option?
> 
> Thank you,

Hello Morgan,

There were several reasons we removed the Custom Region (CR) support
that had been included in FLASH 4-alpha and 4-beta:

  * The feature was only ever supported with the split (PPM) Hydro solver.
    At the Flash Center we are now focussing on using and developing the 
    unsplit solvers (for both Hydro and MHD). The existing CR support
    could not easily be ported from the split to the unsplit solvers.
  * At least one important purpose of the CR code, namely that of
    representing obstacles that are placed in the fluid flow, is now
    better served by "rigid body" handling available in unsplit solvers.
  * The CR support required calls from various places within Hydro code 
    to the supporting Grid routines; these got in the way of some code 
    development work in Hydro (even split).
  * Nobody at the FLASH Center was actively using CR; we were not aware
    of anyone outside the Center using it; and thought it unlikely that
    users had already adopted the feature.

Please let us know if you have found the CR functionality useful and want 
to continue using it.  If there is some interest, we could provide a 
patch, applicable to the 4.0 release code, that would reinstate the 
functionality.

Klaus