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 * Copyright (C) 1997-2015 by Dimitri van Heesch.
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/*! \page formulas Including formulas 

Doxygen allows you to put \LaTeX formulas in the
output (this works only for the HTML, \LaTeX and RTF output. To be able to include 
formulas (as images) in the HTML and RTF documentation, you will also need to 
have the following tools installed
<ul>
<li>\c latex: the \LaTeX compiler, needed to parse the formulas. 
    To test I have used the teTeX 1.0 distribution.
<li>\c dvips: a tool to convert DVI files to PostScript files 
    I have used version 5.92b from Radical Eye software for testing.
<li>\c gs: the GhostScript interpreter for converting PostScript files 
    to bitmaps. I have used Aladdin GhostScript 8.0 for testing.
</ul>
For the HTML output there is also an alternative solution using
<a href="https://www.mathjax.org">MathJax</a> which does not
require the above tools. If you enable \ref cfg_use_mathjax "USE_MATHJAX" in
the configuration then the latex formulas will be copied to the HTML "as is" and a
client side javascript will parse them and turn them into (interactive) images.

There are four ways to include formulas in the documentation.
<ol>
<li>Using in-text formulas that appear in the running text. 
    These formulas should be put between a pair of \ref cmdfdollar "\\f\$"
    commands, so
\verbatim
  The distance between \f$(x_1,y_1)\f$ and \f$(x_2,y_2)\f$ is 
  \f$\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\f$.
\endverbatim results in:

  The distance between \f$(x_1,y_1)\f$ and \f$(x_2,y_2)\f$ is 
  \f$\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\f$.
<br>
<li>Using in-text formulas that appear in the running text, contrary to
    \ref cmdfdollar "\\f$" it will not explicitly open the math mode in \LaTeX.
    These formulas should be put between \ref cmdfrndclose "\\f(" and
    \ref cmdfrndopen "\\f)" commands, so
\verbatim
  The LaTeX and Tex logos are: \f(\LaTeX \f) and \f(\TeX \f).
\endverbatim results in:

  The LaTeX and Tex logos are: \f(\LaTeX \f) and \f(\TeX \f).
<br>
<li>Unnumbered displayed formulas that are centered on a separate line.
    These formulas should be put between \ref cmdfbropen "\\f[" and
    \ref cmdfbrclose "\\f]" commands.
    An example:
\verbatim
  \f[
    |I_2|=\left| \int_{0}^T \psi(t) 
             \left\{ 
                u(a,t)-
                \int_{\gamma(t)}^a 
                \frac{d\theta}{k(\theta,t)}
                \int_{a}^\theta c(\xi)u_t(\xi,t)\,d\xi
             \right\} dt
          \right|
  \f]
\endverbatim
  results in:
  \f[
    |I_2|=\left| \int_{0}^T \psi(t) 
             \left\{ 
                u(a,t)-
                \int_{\gamma(t)}^a 
                \frac{d\theta}{k(\theta,t)}
                \int_{a}^\theta c(\xi)u_t(\xi,t)\,d\xi
             \right\} dt
          \right|
  \f]
<li>Formulas or other latex elements that are not in a math 
    environment can be specified using \ref cmdfcurlyopen "\\f{environment}", where
    \c environment is the name of the \LaTeX environment, 
    the corresponding end command is \ref cmdfcurlyclose "\\f}". Here is an example for an 
    equation array
\verbatim
   \f{eqnarray*}{
        g &=& \frac{Gm_2}{r^2} \\ 
          &=& \frac{(6.673 \times 10^{-11}\,\mbox{m}^3\,\mbox{kg}^{-1}\,
              \mbox{s}^{-2})(5.9736 \times 10^{24}\,\mbox{kg})}{(6371.01\,\mbox{km})^2} \\ 
          &=& 9.82066032\,\mbox{m/s}^2
   \f}
\endverbatim
  which results in:
   \f{eqnarray*}
        g &=& \frac{Gm_2}{r^2} \\ 
          &=& \frac{(6.673 \times 10^{-11}\,\mbox{m}^3\,\mbox{kg}^{-1}\,
              \mbox{s}^{-2})(5.9736 \times 10^{24}\,\mbox{kg})}{(6371.01\,\mbox{km})^2} \\ 
          &=& 9.82066032\,\mbox{m/s}^2
   \f}
</ol>
For the first and third commands one should make sure formulas contain 
valid commands in \LaTeX's math-mode.
The second command should valid text-mode commands that also work in math-mode when using
\ref cfg_use_mathjax "USE_MATHJAX".
For the fourth command the section should contain valid command for the specific environment.

\warning Currently, doxygen is not very fault tolerant in recovering 
from typos in formulas. It may be necessary to remove the
files <code>formula.repository</code> that are written to the html, rtf etc. directories to 
get rid of an incorrect formula as well as the <code>form_*</code> files.

To have the possibility to define your own \LaTeX commands, for e.g. formula building blocks
or consistent writing of certain words, the configuration option \ref cfg_formula_macrofile "FORMULA_MACROFILE"
can be used. to supply a file with \LaTeX commands.
This file can contain \LaTeX `\newcommand` and `\renewcommand` commands and they are included
formulas (image version and MathJax version) as well as in the generated \LaTeX output (for PDF generation).<br>
The `\newcommand` (and `\renewcommand`) are restricted to a version without optional
parameters so only the following types are supported:
```
\newcommand{\cmd}{replacement}
\newcommand{\cmd}[nr]{replacement}
```
e.g.
```
\newcommand{\E}{\mathrm{E}}
\newcommand{\ccSum}[3]{\sum_{#1}^{#2}{#3}}
```

\htmlonly
Go to the <a href="tables.html">next</a> section or return to the
 <a href="index.html">index</a>.
\endhtmlonly

*/