User: bmundim Date: 2011/01/24 12:01 PM

Modified: / ET.tex

Log: Following Frank's suggestion of breaking lines around column 80.

File Changes:

Directory: / ============

File [modified]: ET.tex Delta lines: +55 -41 =================================================================== --- ET.tex 2011-01-24 17:52:33 UTC (rev 18) +++ ET.tex 2011-01-24 18:01:31 UTC (rev 19) @@ -414,48 +414,58 @@ \subsection{Initial Data} \todo{1/2 page Josh, Bruno}

-The Einstein Toolkit contains many modules used to generate initial data for GR simulations, -including both vacuum and hydrodynamical configurations. These include modules used primarily -for testing out various components of the evolution scheme as well as physically motivated -configurations that describe single of binary blacks and/or neutron stars. Many of the modules -are self-contained, consisting of either all the code to generate exact initial solutions or -the numerical tools required to construct solutions known semi-analytically. Others, though, -require the installation of other numerical software packages that are included in the toolkit -as External libraries. The {\tt twopunctures} module \cite{Ansorg:2004ds}, commonly used in numerical -relativity to generate binary black hole data, invokes the GNU Scientific Library [GSL; \cite{Galassi:2009}]. -Several modules have also been implemented to read in datafiles generated by the -{\tt Lorene code} \cite{Lorene:web,GGTMB}, including the BHBH, BHNS, and NSNS data made publicly -available through the Lorene website. +The Einstein Toolkit contains many modules used to generate initial data for +GR simulations, including both vacuum and hydrodynamical configurations. +These include modules used primarily for testing out various components of +the evolution scheme as well as physically motivated configurations that +describe single of binary blacks and/or neutron stars. Many of the modules +are self-contained, consisting of either all the code to generate exact +initial solutions or the numerical tools required to construct solutions +known semi-analytically. Others, though, require the installation of other +numerical software packages that are included in the toolkit as External +libraries. The {\tt twopunctures} module \cite{Ansorg:2004ds}, commonly +used in numerical relativity to generate binary black hole data, invokes +the GNU Scientific Library [GSL; \cite{Galassi:2009}]. Several modules +have also been implemented to read in datafiles generated by the {\tt Lorene +code} \cite{Lorene:web,GGTMB}, including the BHBH, BHNS, and NSNS data +made publicly available through the Lorene website.

-Scheduling of initial data routines generally follows a standard format. User-defined parameters -are run through a parameter check designed to catch obvious internal inconsistencies, in addition to -any known incompatibilities with other modules of the toolkit. Initial data is then generated -at the proper stage within the Cactus framework, determined primarily by whether the configuration -in question represents vacuum or a hydrodynamical configuration. Finally, any necessary cleanup -is typically performed at the end of the initial step, prior to the iterations forward in time. +Scheduling of initial data routines generally follows a standard format. +User-defined parameters are run through a parameter check designed to catch +obvious internal inconsistencies, in addition to any known incompatibilities +with other modules of the toolkit. Initial data is then generated at the proper +stage within the Cactus framework, determined primarily by whether the +configuration in question represents vacuum or a hydrodynamical configuration. +Finally, any necessary cleanup is typically performed at the end of the initial +step, prior to the iterations forward in time.

-For vacuum initial data configurations, an initial data module must supply $g_{ij}$, the spatial 3-metric, -and $K_{ij}$, the extrinsic curvature. While the evolution scheme typically makes use of the BSSN formalism, -the conversion between the physical and conformal metric and extrinsic curvature is handled solely within -evolution modules, and is not referenced by initial data ones. Optionally, many initial data modules also -supply values for the lapse and shift vector, and in some cases time derivatives as well, though these -may be supplied by other routines depending on the freedom to choose gauge conditions envisioned for a -specific configuration. +For vacuum initial data configurations, an initial data module must supply +$g_{ij}$, the spatial 3-metric, and $K_{ij}$, the extrinsic curvature. +While the evolution scheme typically makes use of the BSSN formalism, +the conversion between the physical and conformal metric and extrinsic +curvature is handled solely within evolution modules, and is not referenced +by initial data ones. Optionally, many initial data modules also supply values +for the lapse and shift vector, and in some cases time derivatives as well, +though these may be supplied by other routines depending on the freedom +to choose gauge conditions envisioned for a specific configuration.

-For hydrodynamic configurations, assuming that an equation of state has been specified, the user must also -supply the values of hydrodynamic variables at all grid locations, in particular the primitive variables -$\rho$, $v_i$ and the energy variable $\epsilon$ for all cases where we don't have a polytype EOS in the -form $P=P(\rho)$ (see Sec.~\ref{???} for a discussion of the use of EOS in the ET). For an MHD configuration, -one must supply all of these along with the initial magnetic field $B^i$ as well. +For hydrodynamic configurations, assuming that an equation of state has been +specified, the user must also supply the values of hydrodynamic variables +at all grid locations, in particular the primitive variables $\rho$, $v_i$ and +the energy variable $\epsilon$ for all cases where we don't have a polytype EOS +in the form $P=P(\rho)$ (see Sec.~\ref{???} for a discussion of the use of EOS +in the ET). For an MHD configuration, one must supply all of these along with +the initial magnetic field $B^i$ as well.

The initial data routines currently implemented include the following: \begin{itemize} \item Vacuum spacetime tests: \begin{enumerate} -\item {\tt IDConstraintViolate}: A vacuum spacetime in which the diagonal terms in the spatial metric are -modified by a spatial deformation to explicitly violate the Hamiltonian constraint. -\item {\tt Exact}: A set of exact spacetimes in various coordinates, along with tools to Lorentz boost -those configurations. +\item {\tt IDConstraintViolate}: A vacuum spacetime in which the diagonal terms +in the spatial metric are modified by a spatial deformation to explicitly +violate the Hamiltonian constraint. +\item {\tt Exact}: A set of exact spacetimes in various coordinates, along with +tools to Lorentz boost those configurations. \end{enumerate} \item Vacuum gravitational wave configurations: \begin{enumerate} @@ -464,13 +474,17 @@ \end{enumerate} \item Black Hole configurations: \begin{enumerate} -\item {\tt IDAnalyticBH}: This module can generate Schwarzchild black holes, as well as the Misner solution -for multiple BHs and the brill-Lindquist binary BH solution. -\item {\tt IDAxibrillBH,~IDAxiOddBrillBH}: These modules generate single black holes deformed by even and -odd parity axisymmetric perturbations, respectively. -\item {\tt DistortedBHIVP,~RotatingDBHIVP}: These modules generate single black holes distorted by even -and odd-parity non-axisymmetric perturbation, respectivey. -\item {\tt TwoPunctures}: This module generates accurate binary black-hole initial data. +\item {\tt IDAnalyticBH}: This module can generate Schwarzchild black holes, +as well as the Misner solution for multiple BHs and the brill-Lindquist binary +BH solution. +\item {\tt IDAxibrillBH,~IDAxiOddBrillBH}: These modules generate single +black holes deformed by even and odd parity axisymmetric perturbations, +respectively. +\item {\tt DistortedBHIVP,~RotatingDBHIVP}: These modules generate single +black holes distorted by even and odd-parity non-axisymmetric perturbation, +respectivey. +\item {\tt TwoPunctures}: This module generates accurate binary black-hole +initial data. \end{enumerate} \end{itemize}