Legende wird im Balkendiagramm nicht angezeigt

Question

Ich habe ein Balkendiagramm, bei dem einige Datensätze nicht für alle x-Koordinaten Punkte enthalten.

Ich habe zwei Probleme:

1. Legendenbeschriftungen werden nicht angezeigt
2. Das Symbol in der Legende ist ein Doppelbalken. Warum ist das so? Sollte es nicht ein einzelner Balken sein?

Da ich außerdem im Diagramm (nordwestliche Ecke) viel leeren Platz habe, kann ich die Legende dort einfügen?

Danke

\documentclass[preprint,1p,times]{elsarticle}

\usepackage{pgfplots}

\pgfplotsset{height=6cm, compat=1.9}

\begin{document}

\newcommand \SingleName {Single}
\newcommand \DoubleName {Double}
\newcommand \ScalarName {Scalar}
\newcommand \SSEName {SSE}
\newcommand \AVXName {AVX} 

\newcommand \MorinOffsetName {Khuong Offset}
\newcommand \MorinBranchyName {Khuong Branchy}
\newcommand \LowerBoundName{lower\_bound}
\newcommand \BitSetNoPadName{Lead Bit No Pad}
\newcommand \ClassicModName{Classic Mod}

\newcommand \ClassicName {Classic}
\newcommand \ClassicColor {magenta}
\newcommand \ClassicMark {*}
\newcommand \ClassicStyle {solid}

\newcommand \ClassicOffsetName {Offset}
\newcommand \ClassicOffsetColor {green}
\newcommand \ClassicOffsetMark {*}
\newcommand \ClassicOffsetStyle {solid}

\newcommand \BitSetName {Lead Bit}
\newcommand \BitSetColor {green}
\newcommand \BitSetMark {*}
\newcommand \BitSetStyle {solid}

\newcommand \EytzingerName {Eytzinger}
\newcommand \EytzingerColor {blue}
\newcommand \EytzingerMark {*}
\newcommand \EytzingerStyle {solid}

\pgfplotsset{every axis/.append style={
    font=\small,
        line width=0.6pt,
        }}


\begin{figure}[ht]
\begin{tikzpicture}
\begin{axis}[
    width  = 0.85\textwidth,
    height = 5cm,
    major x tick style = transparent,
    ybar=2.5*\pgflinewidth,
    bar width=2.5pt,
    ymajorgrids = true,
    ylabel = {Throughput},
    ytick={0, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600},
    symbolic x coords={\ClassicName,\LowerBoundName,\MorinBranchyName,\MorinOffsetName, \ClassicModName,\ClassicOffsetName,\BitSetName,\EytzingerName},
    xtick = data,
    xticklabel style={rotate=45, anchor=east},
    scaled y ticks = false,
    enlarge x limits=0.08,
    ymin=0,
    legend pos=outer north east,
]

  \addplot[style={red,fill=red,mark=none}]
coordinates {(\EytzingerName,170.465) (\BitSetName,199.79) (\ClassicOffsetName,184.861) (\MorinOffsetName,146.236) (\MorinBranchyName,64.4379) (\ClassicName,53.0333) (\LowerBoundName,62.4723) (\ClassicModName,152.575) };
\addplot[style={orange,fill=orange,mark=none}]
coordinates {(\EytzingerName,171.929) (\BitSetName,199.421) (\ClassicOffsetName,187.638) (\MorinOffsetName,147.191) (\MorinBranchyName,63.5857) (\ClassicName,50.8408) (\LowerBoundName,63.7888) (\ClassicModName,153.149) };
\addplot[style={blue,fill=blue,mark=none}]
coordinates {(\EytzingerName,381.08) (\BitSetName,383.956) (\ClassicOffsetName,379.795) (\ClassicModName,244.268) };
\addplot[style={cyan,fill=cyan,mark=none}]
coordinates {(\EytzingerName,260.645) (\BitSetName,263.8) (\ClassicOffsetName,254.917) (\ClassicModName,151.602) };
\addplot[style={green,fill=green,mark=none}]
coordinates {(\EytzingerName,385.152) (\BitSetName,386.348) (\ClassicOffsetName,381.327) (\ClassicModName,253.413) };

\addplot[style={yellow,fill=yellow,mark=none}]
    coordinates {(\EytzingerName,264.892) (\BitSetName,216.624) (\ClassicOffsetName,214.466) (\ClassicModName,138.059) };

 \legend={\SingleName-\ScalarName,\DoubleName-\ScalarName,\SingleName-\SSEName,\DoubleName-\SSEName,\SingleName-\AVXName,\DoubleName-\AVXName}
 %   \legend={a,b,c,d,e,f}
\end{axis}

\end{tikzpicture}
\vspace*{-5mm}
\caption{Throughput in millions of searches per second with array X of size $N=15$ and array $Z$ of size $M=2048$ randomly generated}
\label{fig:selectbinary}
\end{figure}

\end{document}