diff options
author | jthorn <jthorn@e296648e-0e4f-0410-bd07-d597d9acff87> | 2002-05-30 11:06:42 +0000 |
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committer | jthorn <jthorn@e296648e-0e4f-0410-bd07-d597d9acff87> | 2002-05-30 11:06:42 +0000 |
commit | 1fb1b55b3fd8a4fc61af1822a6cd79e0458ee777 (patch) | |
tree | edb48d93ba954cfc8077cdb224214779bcdcf70d /doc/documentation.tex | |
parent | 0e22df4aec6bfa187d03f0cdf0b0ec85350bab5c (diff) |
remove all user-defined latex macros as per Gabrielle's orders :(
git-svn-id: http://svn.einsteintoolkit.org/cactus/EinsteinInitialData/Exact/trunk@85 e296648e-0e4f-0410-bd07-d597d9acff87
Diffstat (limited to 'doc/documentation.tex')
-rw-r--r-- | doc/documentation.tex | 72 |
1 files changed, 27 insertions, 45 deletions
diff --git a/doc/documentation.tex b/doc/documentation.tex index 43e58e0..52d1792 100644 --- a/doc/documentation.tex +++ b/doc/documentation.tex @@ -2,28 +2,6 @@ \documentclass{article} \usepackage{amsmath} -\def\eqref#1{$(\ref{#1})$} -\def\cf{cf.\hbox{}} -\def\ie{i.e.\hbox{}} -\def\eg{e.g.\hbox{}} -\def\etal{{\it et~al.\/}} -\def\nb{n.b.\hbox{}} -\def\Nb{N.b.\hbox{}} - -\def\tfrac#1#2{{\textstyle \frac{#1}{#2}}} -\def\dfrac#1#2{{\displaystyle \frac{#1}{#2}}} - -\def\half{\tfrac{1}{2}} -\def\third{\tfrac{1}{3}} - -\def\new{\text{new}} -\def\G{{\sf G}} -\def\diag{\operatorname{diag}} -\def\sech{\operatorname{sech}} - -% nicely typeset "C++" (adapted from a comp.lang.C++ FAQ entry) -\def\Cplusplus{\hbox{C\hspace{-.05em}\raisebox{.4ex}{\tiny\bf ++}}} - %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% \begin{document} @@ -132,7 +110,8 @@ types of coordinates: \verb|Exact::exactmodel = "Minkowski"| specifies Minkowski spacetime in the usual Minkowski coordinates: \begin{equation} -g_{ab} = \diag \left[ +g_{ab} = \text{diag} + \left[ \begin{array}{cccc} -1 & 1 & 1 & 1 %%%\\ \end{array} @@ -148,11 +127,11 @@ with the usual Minkowski time slicing, but using the nontrivial spatial coordinates defined as follows: First take the flat metric in polar spherical coordinates, then define a new radial coordinate by \begin{equation} -r = r_\new (1 - a \G(r_\new)) +r = r_\text{new} (1 - a {\sf G}(r_\text{new})) \end{equation} where $a = \verb|Exact::flatfunny_a|$ is a specified parameter with -$a \in [0,1)$, and $\G(r) = \exp(-\half r^2/\sigma^2)$ is a Gaussian -centered at $r=0$ with amplitude~1 and width +$a \in [0,1)$, and ${\sf G}(r) = \exp(-\frac{1}{2} r^2/\sigma^2)$ +is a Gaussian centered at $r=0$ with amplitude~1 and width $\sigma = \verb|Exact::flatfunny_s|$. Finally, transform back to Cartesian coordinates. @@ -165,13 +144,13 @@ with the nontrivial time slicing and spatial coordinates defined as follows: First take the flat 4-metric in polar spherical coordinates, then define a new time coordinate by \begin{equation} -t_\new = t - a \G(r) +t_\text{new} = t - a {\sf G}(r) \end{equation} where $a = \verb|Exact::flatshift_a|$ is a specified parameter with -$a \in (-1,1)$, and $\G(r) = \exp(-\half r^2/\sigma^2)$ is a Gaussian -centered at $r=0$ with amplitude~1 and width +$a \in (-1,1)$, and ${\sf G}(r) = \exp(-\frac{1}{2} r^2/\sigma^2)$ +is a Gaussian centered at $r=0$ with amplitude~1 and width $\sigma = \verb|Exact::flatshift_s|$. Finally, transform back to -Cartesian (4-)coordinates. (\Nb{} this gives a time-independent +Cartesian (4-)coordinates. (N.b.\ this gives a time-independent 4-metric.) %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% @@ -261,14 +240,14 @@ g_{ab} & = \left[ \end{array} \right] \\ -g_{ij} & = \diag +g_{ij} & = \text{diag} \left[ \begin{array}{ccc} 1 + \frac{2m}{r} & r^2 & r^2 \sin^2 \theta %%%\\ \end{array} \right] \\ -K_{ij} & = \diag +K_{ij} & = \text{diag} \left[ \begin{array}{ccc} - \frac{2m^2}{r^2} \frac {1 + \frac{m}{r}} {\sqrt{1 + \frac{2m}{r}}} @@ -344,7 +323,7 @@ There is also a numerical parameter \verb|KerrSchild_eps| which is used to avoid division by zero if a grid point falls exactly at the black hole center; the default setting should be ok for most purposes. -Kerr-Schild coordinates use the same time slicing (\nb{} non-maximal!) +Kerr-Schild coordinates use the same time slicing (n.b.\ non-maximal!) and $z$~spatial coordinate as Kerr coordinates, but define new spatial coordinates $x$ and~$y$ by \begin{equation} @@ -466,7 +445,7 @@ for each $i = 1$, $2$, $3$, $4$. \subsection{Pure-Radiation Robertson-Walker Cosmology} \verb|Exact::exactmodel = "Rob-Wal"| specifies a pure-radiation -Robertson-Walker spacetime ($p = \third \rho$, $k=0$), as described in +Robertson-Walker spacetime ($p = \frac{1}{3} \rho$, $k=0$), as described in Hawking and Ellis section~5.3 and MTW section~27.11 (see also gr-qc/0110031), transformed to the usual Cactus $(t,x,y,z)$ Cartesian-topology coordinates. The physics parameters are @@ -563,7 +542,7 @@ as described in gr-qc/0110031, and in more detail in L. Pimentel, International Journal of Theoretical Physics {\bf 32}(6) [1993], 979, and -S. Gotlober, \etal{}, +S. Gotlober, {\it et.~al.\/}, ``Early Evolution of the Universe and Formation [of] Structure'', Akad. Verlag, 1990. There is one physics parameter, @@ -574,7 +553,8 @@ q = \text{\tt Kasner\_q} %%%\\ In the usual Cactus $(t,x,y,z)$ Cartesian-topology coordinates, the 4-metric is \begin{equation} -g_{ab} = \diag \left[ +g_{ab} = \text{diag} + \left[ \begin{array}{cccc} -1 & t^{2q} & t^{2q} & t^{2-4q} %%%\\ \end{array} @@ -582,12 +562,13 @@ g_{ab} = \diag \left[ \end{equation} and the stress-energy tensor is \begin{equation} -T_{ab} = \diag \left[ +T_{ab} = \text{diag} + \left[ \begin{array}{cccc} - q \dfrac{2 - 3q}{8\pi t^2} - & q \dfrac{(2 - 3q) t^{2q}}{8\pi t^2} - & q \dfrac{(2 - 3q) t^{2q}}{8\pi t^2} - & q \dfrac{(2 - 3q) t^{2-4q}}{8\pi t^2} + q \displaystyle\frac{2 - 3q}{8\pi t^2} + & q \displaystyle\frac{(2 - 3q) t^{2q}}{8\pi t^2} + & q \displaystyle\frac{(2 - 3q) t^{2q}}{8\pi t^2} + & q \displaystyle\frac{(2 - 3q) t^{2-4q}}{8\pi t^2} %%%\\ \end{array} \right] @@ -688,20 +669,21 @@ R(r) = r - A f(r) g(r) Here $A = a$ if \verb|bowl_evolve = "false"|, but is multiplied by a Fermi factor \begin{equation} -A = \dfrac{a}{1 + \exp(-\sigma_t(t-t_0))} +A = \frac{a}{1 + \exp(-\sigma_t(t-t_0))} \end{equation} if \verb|bowl_evolve = "true"|. For this latter case we have flat spacetime far in the past, and a static bowl far in the future. $f(r)$ is either a Gaussian or a Fermi function, \begin{equation} f(r) = \begin{cases} - \exp \left( -\half (r-c)^2/\sigma^2 \right) + \exp \left( -\frac{1}{2} (r-c)^2/\sigma^2 \right) & \text{if {\tt bowl\_type = "Gauss"}} \\[1ex] - \dfrac{1}{1 + \exp(-\sigma(r-c))} + \displaystyle + \frac{1}{1 + \exp(-\sigma(r-c))} & \text{if {\tt bowl\_type = "Fermi"}} %%%\\ \end{cases} \end{equation} -$g(r) = 1 - \sech 4r$ is a fixup factor to ensure that +$g(r) = 1 - \text{sech}(4r)$ is a fixup factor to ensure that $\displaystyle \lim_{r \to 0} R(r) = r$. The three extra paramters $(\delta x, \delta y, \delta z)$ |