Status of the code

Note: This needs an update

Whisky relies on a number of thorns which are in different stages of development. Here we give a basic overview of what each thorn does and should do. The links will give more details.

Whisky

Provides the hydro variables and the evolution routines. Calculates stress energy terms for a spacetime evolution routine.

The basic routines all seem to work fine. We have good results and convergence for shock tubes, TOV stars (Cowling approximation and dynamic), rotating polytropes, the migration test and the forced collapse of an unstable TOV star. Some testing may still be required for any new run, but it seems solid.

Whisky_Init_Data

Provides some simple initial data, such as shock tubes (just simple cases right now) and TOV stars. Shock tubes work fine. TOV routines require LSODA and are largely untested; currently we're using RNSID or the separate TOVSolver thorns.

Whisky_RNSID

Provides initial data for hydro and spacetime variables for a single neutron star. Currently used for the TOV tests as well.

As this is just an interface to the standard RNSID code I think we can say this has been well tested, with one exception: you can't have a point exactly on the origin at the moment.

Whisky_TOVSolver

Provides initial data for hydro and spacetime variables for a TOV star. Works fine but doesn't do boosted solutions or include support for the static conformal factor as yet. Will provide up to 10 TOV stars "glued" together in various ways along with various perturbations. To make these configurations a solution of the field equations you must use the IVP solver.

Whisky_IVP

Given an initial guess for a solution of Einstein's equations with matter this thorn uses BAM to solve the York-Lichnerowicz initial value problem. Normally used for perturbations of solutions generated by RNSID or TOV_Solver.

Works ok for NS problems. Note that using BAM is always a bit tricksy.

EOS_Base

Allows the registration of multiple equations of state which can be chosen between at run time.

Works fine. Is also used by GRAstro_Hydro.

EOS_Ideal_Fluid

An implementation of the ideal gas EOS to use with EOS_Base.

Works fine. Is also used by GRAstro_Hydro.

EOS_Polytrope

An implementation of a polytropic EOS that uses EOS_Base.

This is a fudge, as EOS_Base isn't really designed for a polytropic EOS. However it works and provides all that we require with the minimum of code rewriting. Stupid choice of name, though.

ADMBase

Provides spacetime variables and some other utility routines.

This is the standard Cactus thorn from CactusEinstein. For our purposes it just provides the spacetime variables.

ADMCoupling

Couples the fluid / spacetime variables (it's a Cactus thing and doesn't do anything interesting)

StaticConformal

Provides the static conformal factor. As we currently have no initial data that uses a conformal factor, this is just used for compatibility.

BSSN_MoL

Evolves the spacetime using the BSSN formulation of Einstein's equations.

This is essentially the standard spacetime evolver used for black hole runs at AEI, tweaked to use MoL. Is pretty constantly tested. In the long term will be merged back into the standard ADM_BSSN.

ADMConstraints

The standard thorn from CactusEinstein.

MoL

Generalized time integration.

This works fine with the current codes. However at the moment it (still) won't do mesh refinement properly. However, MoL2 does; speak to IH if you need to use it.

This page is maintained by Ian Hawke.

Impressum.