[Developers] patch: include amsmath package in cactus latex format

[Jonathan Thornburg]

Summary
=======
  doc/latex/cactus.sty  already includes 9 widely-available latex packages.
I propose that we add a 10th, the  amsmath  package.  This would provide
math-formatting capabilities which are currently lacking, and which
would be useful in writing Cactus thorn documentation.


Details
=======
In current-CVS cactus, equation numbers are just integers.  For example,
if (in a thorn guide documentation.tex file) I write

   As implemented here, the shift condition is
   \begin{eqnarray}
   \partial_t \beta^i      & = &   B^i                                     \\
   \partial_t B^i          & = &   F(\alpha) \partial_t \tilde{\Gamma}^i
                                   - \eta B^i                              %%%\\
   \end{eqnarray}
   or
   \begin{eqnarray}
   \partial_t \beta^i      & = &   F(\alpha) B^i                           \\
   \partial_t B^i          & = &   \partial_t \tilde{\Gamma}^i - \eta B^i  %%%\\
   \end{eqnarray}
   where in all cases
   \begin{equation}
   F(\alpha) = \frac{3}{4} \alpha
   \end{equation}

there is no way to have the first pair of equations numbered (1a) and (1b)
and the second pair numbered (2a) and (2b), and \label these so I can
later refer to equations (1) and (2) in describing a parameter which
selects one or the other.

Currently, doc/latex/cactus.sty includes

   \RequirePackage[latin9]{inputenc}
   \RequirePackage{fancyhdr}
   \RequirePackage{graphicx}
   \RequirePackage{latexsym}
   \RequirePackage{amssymb}
   \RequirePackage{ifthen}
   \RequirePackage{calc}
   \RequirePackage{thumbpdf}
   \RequirePackage{hyperref}

I propose that we add the  amsmath  package to this list (patch attached).


Among other useful features, this defines a  subequations  environment,
which nicely solves my problem:

   As implemented here, the shift condition is
   \begin{subequations}
   \label{EvolvedShift/eqn-Gamma-driver-weak-freezing}
   \begin{eqnarray}
   \partial_t \beta^i      & = &   B^i                                     \\
   \partial_t B^i          & = &   F(\alpha) \partial_t \tilde{\Gamma}^i
                                   - \eta B^i                              %%%\\
   \end{eqnarray}
   \end{subequations}
   or
   \begin{subequations}
   \label{EvolvedShift/eqn-Gamma-driver-strong-freezing}
   \begin{eqnarray}
   \partial_t \beta^i      & = &   F(\alpha) B^i                           \\
   \partial_t B^i          & = &   \partial_t \tilde{\Gamma}^i - \eta B^i  %%%\\
   \end{eqnarray}
   \end{subequations}
   where in all cases
   \begin{equation}
   F(\alpha) = \frac{3}{4} \alpha
   \end{equation}

   This is controlled by the Boolean parameter \verb|strong_freezing|:
   If this is false, we have the first
   choice~\eqref{EvolvedShift/eqn-Gamma-driver-weak-freezing},
   since $\alpha \to 0$ implies only $\partial_{tt} \beta^i \to 0$.
   If this is true, we have the second
   choice~\eqref{EvolvedShift/eqn-Gamma-driver-strong-freezing},
   since $\alpha \to 0$ then implies $\partial_t \beta^i \to 0$.

Comments?

ciao,

-- 
-- Jonathan Thornburg <jthorn at aei.mpg.de>
    Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein-Institut),
    Golm, Germany, "Old Europe"     http://www.aei.mpg.de/~jthorn/home.html
    "Washing one's hands of the conflict between the powerful and the
     powerless means to side with the powerful, not to be neutral."
                                       -- quote by Freire / poster by Oxfam
-------------- next part --------------
Index: cactus.sty
===================================================================
RCS file: /cactusdevcvs/Cactus/doc/latex/cactus.sty,v
retrieving revision 1.22
diff -u -r1.22 cactus.sty
--- cactus.sty	2 Jun 2005 20:03:47 -0000	1.22
+++ cactus.sty	4 Jun 2005 13:27:43 -0000
@@ -47,6 +47,7 @@
 \RequirePackage{graphicx}
 \RequirePackage{latexsym}
 \RequirePackage{amssymb}
+\RequirePackage{amsmath}
 \RequirePackage{ifthen}
 \RequirePackage{calc}
 \RequirePackage{thumbpdf}