\pgfplotsset{
compat=1.11,
legend image code/.code={
\draw[mark repeat=2,mark phase=2]
plot coordinates {
(0cm,0cm)
(0.0cm,0cm)        %% default is (0.3cm,0cm)
(0.0cm,0cm)         %% default is (0.6cm,0cm)
};%
}
}
\begin{figure}
  \begin{subfigure}[b]{\textwidth}
    \begin{tikzpicture}
      \begin{axis}[tick style = {draw = none}, width = \textwidth,
        height = 0.6\textwidth, ymin = 0.92, legend style={at={(0.9825,0.75)},anchor=north east},
        xlabel = {epoch}, ylabel = {Classification Accuracy}]
        \addplot table
        [x=epoch, y=val_accuracy, col sep=comma, mark = none]
        {Plots/Data/adagrad.log}; 
        \addplot table
        [x=epoch, y=val_accuracy, col sep=comma, mark = none]
        {Plots/Data/adadelta.log}; 
        \addplot table
        [x=epoch, y=val_accuracy, col sep=comma, mark = none]
        {Plots/Data/adam.log}; 
        
         \addlegendentry{\footnotesize{ADAGRAD}}
        \addlegendentry{\footnotesize{ADADELTA}}
        \addlegendentry{\footnotesize{ADAM}}
        \addlegendentry{SGD$_{0.01}$}
      \end{axis}
    \end{tikzpicture}
    %\caption{Classification accuracy}
  \end{subfigure}
  \begin{subfigure}[b]{\textwidth}
    \begin{tikzpicture}
      \begin{axis}[tick style = {draw = none}, width = \textwidth,
        height = 0.6\textwidth, ymax = 0.5,
        xlabel = {epoch}, ylabel = {Error Measure\vphantom{y}},ytick ={0,0.1,0.2,0.3,0.4,0.45,0.5}, yticklabels =
        {0,0.1,0.2,0.3,0.4,\phantom{0.94},0.5}]
        \addplot table
        [x=epoch, y=val_loss, col sep=comma, mark = none] {Plots/Data/adagrad.log};
        \addplot table
        [x=epoch, y=val_loss, col sep=comma, mark = none] {Plots/Data/adadelta.log};
        \addplot table
        [x=epoch, y=val_loss, col sep=comma, mark = none] {Plots/Data/adam.log};
        
        \addlegendentry{\footnotesize{ADAGRAD}}
        \addlegendentry{\footnotesize{ADADELTA}}
        \addlegendentry{\footnotesize{ADAM}}
        \addlegendentry{SGD$_{0.01}$}
        
      \end{axis}
    \end{tikzpicture}
    \caption{Performance metrics during training}
  \end{subfigure}
  \\~\\
  \begin{subfigure}[b]{1.0\linewidth}
    \begin{tabu} to \textwidth {@{}  *3{X[c]}c*3{X[c]} @{}}
      \multicolumn{3}{c}{Classification Accuracy}
      &~&\multicolumn{3}{c}{Error Measure}
      \\\cline{1-3}\cline{5-7}
      ADAGRAD&ADADELTA&ADAM&&ADAGRAD&ADADELTA&ADAM
      \\\cline{1-3}\cline{5-7}
      1&1&1&&1&1&1
    \end{tabu}
    \caption{Performace metrics after 20 epochs}
  \end{subfigure}
  \caption{Classification accuracy on the test set and ...Performance metrics of the network given in ... trained
    with different optimization algorithms}
\end{figure}
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