Documentation of Arh2 file format ver. 3.0 added

doc/arh2_file_format.tex

+\documentclass[10pt,a4paper]{article}
+\usepackage[utf8]{inputenc}
+\usepackage{amsmath}
+\usepackage{amsfonts}
+\usepackage{amssymb}
+\usepackage{graphicx}
+\usepackage{hyperref}
+\usepackage{longtable}
+
+\author{Simon Praetorius}
+\date{2015-03-02}
+\title{File format description for ARH2 Version 3.0}
+
+\begin{document}
+\maketitle
+\begin{abstract}
+This document describes the AMDiS Refinement Hierarchy 2 (ARH2) File format, version 3.0. The file format includes a description of the refinement of mesh-elements and value containers for the degrees of freedom (DOFs) for a given Finite Element. The concrete definition of finite elements is thereby described in a separate file format (AMDiS Finite Element Description (AFED) ) given elsewhere.
+
+Historically the ARH2 format is based on the ARH format from 1970 (* placeholder for the actual date).
+
+Please send comments on ARH2 to the AMDiS form:\\ \url{https://fusionforge.zih.tu-dresden.de/forum/?group_id=11}\\or post the comments on the Wiki:\\
+\url{https://fusionforge.zih.tu-dresden.de/plugins/mediawiki/wiki/amdis}
+\end{abstract}
+
+\section{Version history}
+\begin{description}
+\item[Version 3.0: March 02, 2015] Definition and description of Finite Elements was restructured and extracted from the ARH2 file format and put into a new file format. A new container format for parallel files (pARH) was added.
+
+\item[Version 2.1: June 01, 2014*] A zlib compression for the file was added.
+
+\item[Version 2.0: January 01, 2014*] First official release of the ARH2 file format. The format consists of two parts, the \textit{header} and the \textit{body}. The header contains the general information about the content in this file, the format version number, the header size, dimensions, a macro table, an simplified Finite Element description and a value table. The header is followed by body structure for each macro element, which includes mesh structure code and DOF value vectors. 
+\end{description}
+
+\section{The file format}
+The ARH2 file format consists of three sections: 
+\begin{enumerate}
+\item The first section contains a file format descriptor and version informations. This can be used to distinguish between the old ARH format and the ARH2 format and all of its versions, i.e. test whether the reader supports the actual format.
+
+\item The second part contains header information about the data stored in the file. This contains information about the dimension of the mesh and the elements, amount of data stored in the file and some flags concerning the data format and compression of the data.
+
+\item The third part contains information about the macro-elements stored in the file, about the different finite elements spaces of the value vectors stored in the file and a list of the value vectors including addition information used to extract only parts of the data from file.
+
+\item The last block contains for all macro element the structure code (an information how to refine a macro element) and all values stored on this macro element.
+\end{enumerate}
+
+The concrete structure is given in the table below:
+\begin{longtable}{p{.2\textwidth}|p{.12\textwidth}|p{.1\textwidth}|p{.58\textwidth}}
+\textbf{Field} & \textbf{Size (B)} & \textbf{Type} & \textbf{Description} \\\hline\hline\endhead
+\hline\multicolumn{4}{r}{\textit{Continued on next page}}\\\hline\endfoot
+\endlastfoot
+fd & 4 & string & Format descriptor (lower case) [\texttt{sarh}] \\
+maj & 1 & uchar & major version [3] \\
+min & 1 & uchar & minor version [0] \\\hline
+hs & 4 & uint & header size (until = line) \\
+dow & 4 & uint & dimension of world \\
+dim & 4 & uint & dimension of the mesh \\
+num\_fes & 4 & uint & number of Finite Element spaces \\
+num\_vec & 4 & uint & number of value vectors \\
+num\_el & 4 & uint & number of macro elements \\
+cps & 4 & int & compression flag: 0... no compression, 1... ZLib compression\footnote{Details of ZLib Version, Parameters etc.} \\\hline\hline
+
+\end{longtable}
+
+\end{document}
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