Til brug med PGFplots

preamble.tex

% Use this package to plots from MATLAB
\usepackage{pgfplots}
\definecolor{blue}{rgb}{ 0    0.4470    0.7410}
\definecolor{red}{rgb}{0.6350    0.0780    0.1840}
\definecolor{orange}{rgb}{0.8500    0.3250    0.0980}
\definecolor{yellow}{rgb}{0.9290    0.6940    0.1250}
\definecolor{purple}{rgb}{ 0.4940    0.1840    0.5560}
\definecolor{green}{rgb}{  0.4660    0.6740    0.1880}
\pgfplotsset{compat=1.5.1}
\usepackage{tikz}
\usepgfplotslibrary{external}
\tikzexternalize[prefix=tikz/]

\usetikzlibrary{decorations.markings}
\usetikzlibrary{pgfplots.groupplots}
\usetikzlibrary{arrows,shapes,positioning,angles,spy}

\usepackage{pgfplotstable}

% Style to select only points from #1 to #2 (inclusive)
\pgfplotsset{select coords between index/.style 2 args={
    x filter/.code={
        \ifnum\coordindex<#1\def\pgfmathresult{}\fi
        \ifnum\coordindex>#2\def\pgfmathresult{}\fi
    }
}}

\pgfplotsset{ylabsh/.style={every axis y label/.style={at={(0,0.5)}, xshift=#1, rotate=90}}}

\makeatletter
\pgfplotsset{
    groupplot xlabel/.initial={},
    every groupplot x label/.style={
        at={($({\pgfplots@group@name\space c1r\pgfplots@group@rows.west}|-{\pgfplots@group@name\space c1r\pgfplots@group@rows.outer south})!0.5!({\pgfplots@group@name\space c\pgfplots@group@columns r\pgfplots@group@rows.east}|-{\pgfplots@group@name\space c\pgfplots@group@columns r\pgfplots@group@rows.outer south})$)},
        anchor=north,
    },
    groupplot ylabel/.initial={},
    every groupplot y label/.style={
            rotate=90,
        at={($({\pgfplots@group@name\space c1r1.north}-|{\pgfplots@group@name\space c1r1.outer
west})!0.5!({\pgfplots@group@name\space c1r\pgfplots@group@rows.south}-|{\pgfplots@group@name\space c1r\pgfplots@group@rows.outer west})$)},
        anchor=south
    },
    execute at end groupplot/.code={%
      \node [/pgfplots/every groupplot x label]
{\pgfkeysvalueof{/pgfplots/groupplot xlabel}};  
      \node [/pgfplots/every groupplot y label] 
{\pgfkeysvalueof{/pgfplots/groupplot ylabel}};  
    }
}

\def\endpgfplots@environment@groupplot{%
    \endpgfplots@environment@opt%
    \pgfkeys{/pgfplots/execute at end groupplot}%
    \endgroup%
}

\makeatother