Hi Erik,

Frank suggested you might be an appropriate person to ask about elliptic solver thorns that work in the current release of ET. I have, as you know, built Hilbert and have built the development version.  

I am wanting to write a thorn which prepares a geon, approximated by initial data which has toroidal symmetry and is bounded. The desired distribution would be placed on the r axis in cylindrical coordinates and have a gaussian distribution. In the actual application, of course the initial data would be interpolated onto a Cartesian coordinate mesh or meshes.  I just want to solve the Hamiltonian constraint and have the initial data be time-symmetric. This sounds like a pretty simple thing to do. I think I could start with Brill and put q to my purposes and pretty much get out what I want.  However, the IDBrill does not seem to work.  Also, I am wondering what kinds of elliptic solvers you know of that are fully supported in ET?  Frank mentioned a petsc thorn. It does not get downloaded and built by default and looking at the einsteintoolkit.th file it is mentioned in:

# CactusElliptic thorns

!TARGET   = $ARR

!TYPE     = git

!URL      = https://bitbucket.org/cactuscode/cactuselliptic.git

!REPO_PATH= $2

!CHECKOUT = CactusElliptic/EllPETSc CactusElliptic/TATPETSc

CactusElliptic/EllBase

#DISABLED CactusElliptic/EllPETSc

CactusElliptic/EllSOR

CactusElliptic/TATelliptic

#DISABLED CactusElliptic/TATPETSc

However, what's with the DISABLED reference to EllPETSc is a bit concerning. So before I go though the exercise to look more into the EllPETSc, I thought  I'd ask whether the EllPETSc thorn is fully compatible with Hilbert?

Can you thus please bring me up to the current moment on just what elliptic solvers are in use for initial data construction in Hilbert?  I know many people have been focussing on the multiple BH problem, so there's not much traffic anymore about Brill.  I do want to run Brill though and also do the "geon" problem.

Thanks for your advice and any pointers you can give.