Error in matlab2tikz

matlab2tikztikz-pgf

I am attempting to plot two graphs together in one plot using matlab2tikz and I am facing a basic syntax issue that I have been trying hours to search for.

The error is as follow:
Extra }, or forgotten \endgroup. I have referenced the line overleaf saying its causing the error in the code below.

I have rewrote the code below but with exculding the I/O data vector because they are too large to be fitted in this tex-exchange website.

% This file was created by matlab2tikz.
%
%The latest updates can be retrieved from
%  http://www.mathworks.com/matlabcentral/fileexchange/22022-matlab2tikz-matlab2tikz
%where you can also make suggestions and rate matlab2tikz.
%
\documentclass[12pt,english]{article}
\usepackage{pgfplots}
\usepackage{tikz}
\usetikzlibrary{fadings}
\usetikzlibrary{patterns}
\usetikzlibrary{shadows.blur}
\usetikzlibrary{shapes}
\usetikzlibrary{plotmarks}
\usetikzlibrary{arrows.meta}
\usepgfplotslibrary{patchplots}

\begin{document}
\begin{tikzpicture}

\begin{axis}[%
width=4.448in,
height=3.461in,
at={(0.831in,0.481in)},
scale only axis,
separate axis lines,
every outer x axis line/.append style={white!40!black},
every x tick label/.append style={font=\color{white!40!black}},
every x tick/.append style={white!40!black},
xmin=1,
xmax=411,
every outer y axis line/.append style={white!40!black},
every y tick label/.append style={font=\color{white!40!black}},
every y tick/.append style={white!40!black},
ymin=-1,
ymax=0.8,
ylabel style={font=\color{white!40!black}},
ylabel={y1},
axis background/.style={fill=white},
legend style={legend cell align=left, align=left, draw=white!15!black}
]
\addplot [color=white!60!black, forget plot]
  table[row sep=crcr]{%
1   0.2845\\
2   0.2365\\
3   0.0805\\
4   -0.0615\\
5   -0.0115\\
6   -0.1195\\
7   -0.1795\\
8   -0.1185\\
9   -0.2065\\
10  -0.1515\\
11  -0.0105\\
12  0.0485\\
13  0.2055\\
14  0.2975\\
15  0.3405\\
16  0.4775\\
17  0.5205\\
18  0.5275\\
19  0.6015\\
20  0.6165\\
};
\addlegendentry{m1: 88.97\%}
\end{axis}%%%%%%%%%%%%OVERLEAF IS POINTING TOWARDS THIS LINE AS SOURCE OF ERROR

\begin{axis}[%
width=4.521in,
height=3.566in,
at={(0.758in,0.481in)},
scale only axis,
separate axis lines,
every outer x axis line/.append style={white!40!black},
every x tick label/.append style={font=\color{white!40!black}},
every x tick/.append style={white!40!black},
xmin=1,
xmax=411,
every outer y axis line/.append style={white!40!black},
every y tick label/.append style={font=\color{white!40!black}},
every y tick/.append style={white!40!black},
ymin=0,
ymax=1,
axis line style={draw=none},
ticks=none
]
\addplot [color=white!60!black, forget plot]
  table[row sep=crcr]{
1   0.284500056219376\\
2   0.23650004412451\\
3   0.0805000155159026\\
4   -0.0615000481945472\\
5   -0.0115000863989766\\
6   -0.119500047731206\\
7   -0.1794999297787\\
8   -0.118499920917993\\
9   -0.206499892438547\\
10  -0.1514999680987\\
11  -0.0105000375051933\\
12  0.0484998970746079\\
13  0.2054999375486\\
14  0.297499996486305\\
15  0.340500089571283\\
16  0.477500053171494\\
17  0.520500116898769\\
18  0.527499974522247\\
19  0.601499983679697\\
20  0.616499933860055\\
};
\end{axis} 

\begin{axis}[%
width=4.521in,
height=3.566in,
at={(0.758in,0.481in)},
scale only axis,
xmin=0,
xmax=1,
xtick={\empty},
xlabel={Time (seconds)},
ymin=0,
ymax=1,
ytick={\empty},
ylabel={Amplitude},
axis line style={draw=none},
ticks=none,
title style={font=\bfseries},
title={Simulated Response Comparison},
axis x line*=bottom,
axis y line*=left
]
\end{axis}
\end{tikzpicture}%

\end{document}

I hope someone can help me figure out what's causing this error.

Update:

As per Marijn's recommendation I have removed forget plot and I ran the code again on the original data and obtained the following output:

However, the simulated output on MATLAB looks like this:

Best Answer

The output from automatic conversion scripts like matlab2tikz, svg2tikz, dot2tex and others is often more complex than needed, causing deficiencies in the output or even errors. This is not necessarily to be blamed on these scripts themselves, as automatic conversion is a very difficult problem - however often it is a better solution to write the pgfplots code yourself from scratch or to export the plots from your original program as PDF and include them as-is.

However, for the current plot some simplifications are possible that seem to approach the original output.

First I removed the final plot that was just adding the title, and added a title option in the first axis.

Second I removed the separate \begin{axis} \end{axis} environments for the two plots and put them together in a single axis environment with two \addplot table statements in the body of the environment, which is the normal procedure when you want to plot multiple lines. This also removes the need for forget plot which was causing the error.

Third I added the axis titles and modified the second plot attributes to be red and dashed, and added the two \addlegendentry statements in the right order. Just for the MWE I also moved the legend to the bottom right (south east) position not to overlap with the plot lines.

MWE:

\documentclass[12pt,english]{article}
\usepackage{pgfplots}
\usepackage{tikz}
\usetikzlibrary{fadings}
\usetikzlibrary{patterns}
\usetikzlibrary{shadows.blur}
\usetikzlibrary{shapes}
\usetikzlibrary{plotmarks}
\usetikzlibrary{arrows.meta}
\usepgfplotslibrary{patchplots}

\begin{document}
\begin{tikzpicture}

\begin{axis}[%
width=4.448in,
height=3.461in,
at={(0.831in,0.481in)},
scale only axis,
separate axis lines,
every outer x axis line/.append style={white!40!black},
every x tick label/.append style={font=\color{white!40!black}},
every x tick/.append style={white!40!black},
xmin=1,
xmax=25,%411,
every outer y axis line/.append style={white!40!black},
every y tick label/.append style={font=\color{white!40!black}},
every y tick/.append style={white!40!black},
ymin=-1,
ymax=0.8,
ylabel style={font=\color{white!40!black}},
ylabel={\textcolor{black}{Amplitude} (y1)},
xlabel={Time (seconds)},
title={Simulated Response Comparison},
axis background/.style={fill=white},
legend style={legend cell align=left, align=left, draw=white!15!black},
legend pos=south east,
]
\addplot [color=white!60!black]%, forget plot]
  table[row sep=crcr]{%
1   0.2845\\
2   0.2365\\
3   0.0805\\
4   -0.0615\\
5   -0.0115\\
6   -0.1195\\
7   -0.1795\\
8   -0.1185\\
9   -0.2065\\
10  -0.1515\\
11  -0.0105\\
12  0.0485\\
13  0.2055\\
14  0.2975\\
15  0.3405\\
16  0.4775\\
17  0.5205\\
18  0.5275\\
19  0.6015\\
20  0.6165\\
};
\addplot [color=red,dashed]%, forget plot]
  table[row sep=crcr]{
1   0.284500056219376\\
2   0.23650004412451\\
3   0.0805000155159026\\
4   -0.0615000481945472\\
5   -0.0115000863989766\\
6   -0.119500047731206\\
7   -0.1794999297787\\
8   -0.118499920917993\\
9   -0.206499892438547\\
10  -0.1514999680987\\
11  -0.0105000375051933\\
12  0.0484998970746079\\
13  0.2054999375486\\
14  0.297499996486305\\
15  0.340500089571283\\
16  0.477500053171494\\
17  0.520500116898769\\
18  0.527499974522247\\
19  0.601499983679697\\
20  0.616499933860055\\
};
\addlegendentry{val\_dat (y1)}
\addlegendentry{m1: 88.97\%}
\end{axis} 
\end{tikzpicture}%

\end{document}

Result:

Option 1 - Setting width and height

When using matlab2tikz you can specify the width and height of figures:

matlab2tikz('nameoffile.tex','width','8cm','height','4cm');

Note that, if I remember correctly, this will set the size of just the axis. Hence, the total width will be 8cm + the width of yticks, ylabel, and other stuff next to the axis itself.

This won't help you with scaling the plots on the LaTeX end of course, but what you can do instead is to set the width to macros that you define in your LaTeX document. For example, you can say

matlab2tikz('nameoffile.tex','width','\figW','height','\figH');

in Matlab, and have a LaTeX file such as

\documentclass{article}
\usepackage{pgfplots,amsmath}

\newlength\figH
\newlength\figW
\setlength{\figH}{4cm}
\setlength{\figW}{8cm}

\begin{document}

Some text, then a centred plot:

\begin{center}
\input{firstplot}
\end{center}

More text, then a wider plot:

\begin{center}
\setlength{\figW}{10cm} % when added inside the  center environment it has no effect outside it
\input{secondplot}
\end{center}

\end{document}

Option 2 - Adding a scale parameter

You also have the option to specify additional options for the tikzpicture and axis environments generated by matlab2tikz. This way you can set a scale parameter for one of them, and have a macro holding the value. In Matlab, do

matlab2tikz('nameoffile.tex','extraAxisOptions','scale=\figurescale');

and have a LaTeX file as

\documentclass{article}
\usepackage{pgfplots,amsmath}

\newcommand\figurescale{1} % set default scaling to 1

\begin{document}

Some text, then a centred plot:

\begin{center}
\input{firstplot}
\end{center}

More text, then a twice as wide plot:

\begin{center}
\renewcommand{\figurescale}{2} % when added inside the  center environment it has no effect outside it
\input{secondplot}
\end{center}

\end{document}

Adding the scale parameter to the axis will not change the size of tick labels and axis labels. If you use 'extraTikzpictureOptions','scale=\figurescale in the call to matlab2tikz, instead of 'extraAxisOptions', scaling will change the size of axis labels etc.

Option 3 - the `tikzscale` package

(I totally forgot to add this option, which is actually quite convenient. SOrry about that.)

The tikzscale package modifies the \includegraphics command so that it can be used instead of \input for .tikz files, and the same scaling options can be used.

Note that you must use .tikz as the file ending, .tex is not recognized.

A quick code example:

\documentclass{article}%

\usepackage{pgfplots,filecontents}
\usepackage{tikzscale}

% the filecontents environment writes its content to the specified file
\begin{filecontents*}{fig.tikz}
\begin{tikzpicture}
\begin{axis}
\addplot{x};
\end{axis}
\end{tikzpicture}
\end{filecontents*}
\begin{document}

\includegraphics{fig.tikz}

\includegraphics[width=.7\linewidth]{fig.tikz}

\includegraphics[height=6cm]{fig.tikz}

\end{document}

Lastly a note about your second code snippet:

\begin{figure}[scale=0.5]
\center
\input{/path/fig.tex}
\end{figure}

There are two things that are wrong here.

The figure environment is just a floating container in which you can put stuff, such as images. It has no options for scaling or similar, so [scale=0.5] does nothing here.
The correct command for centering is \centering, not \center. There is also a center environment, used as \begin{center} ... \end{center}, but within figures it is recommended to use \centering (see Should I use center or centering for figures and tables?).

Best Answer

Related Solutions

[Tex/LaTex] tikz+matlab2tikz

Option 1 - Setting width and height

Option 2 - Adding a scale parameter

Option 3 - the tikzscale package

Related Question

Option 3 - the `tikzscale` package