Undefined control sequence, table\resizebox

Question

I have the following table:

\begin{table}[ht]
\centering
\resizebox{\linewidth}{!}{%
\begin{tabular}{|l|c|c|l|l|l|l|}
\hline
\multirow{2}{*}{\textbf{}} & \multicolumn{6}{c|}{\textbf{Metric}} \\ \cline{2-7} 
 & \multicolumn{3}{c|}{\textbf{SSIM}} & \multicolumn{3}{c|}{\textbf{IoU/F1}} \\ \hline
\textbf{Model} & \multicolumn{1}{l|}{\textbf{Max.}} & \multicolumn{1}{l|}{\textbf{Mean}} & \textbf{Min.} & \textbf{Max.} & \textbf{Mean} & \textbf{Min.} \\ \hline
\textbf{EfficientNetB7} & \textbf{0.956} & \textbf{0.877} & \textbf{0.761} & \textbf{0.988} & \textbf{0.952} & \textbf{0.897} \\ \hline
InceptionV3 & 0.944 & 0.863 & 0.758 & 0.977 & 0.947 & 0.894 \\ \hline
InceptionResNetV2 & 0.941 & 0.859 & 0.743 & 0.983 & 0.943 & 0.886 \\ \hline
DenseNet201 & 0.940 & 0.862 & 0.747 & 0.978 & 0.945 & 0.891 \\ \hline
\end{tabular}
}
\caption{Evaluation of the state-of-the-art models. EfficientNetB7 is proven to be the most suitable model with a high SSIM and IoU score.}
\label{tab:evaluation_models}
\end{table}

which compiles with an error of:

Undefined control sequence

The compiler is having trouble understanding a command you have used. Check that the command is spelled correctly. If the command is part of a package, make sure you have included the package in your preamble using \usepackage{...}.

<recently read> \multirow 
                          
l.509 }
       
The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

I was wondering if it is my document or the table that has a problem?

Thanks in advance.

Answer 1

The error message you get informs you about \multirow being undefined. Most likely this is the case because you did not load the multirow package.

In this particular case and since this specific column is empty, you can also just omit \multirow{2}{*}{\textbf{}} entirely.

Additionally to the two before mentioned solutions to getting rid of the error message, there are other issues with this table. Using resizebox in order to make sure a table is as wide as the textwidth distorts the font sizes resulting in a bunch of different and inconsistent font sizes throughout your document. Since your table is narrow enough to not overflow into the margins, just omit the whole \resizebox and you will end up with the following compilable example code:

\documentclass{article}


\begin{document}

\begin{table}[ht]
\centering
\begin{tabular}{|l|c|c|l|l|l|l|}
\hline
& \multicolumn{6}{c|}{\textbf{Metric}} \\ \cline{2-7} 
 & \multicolumn{3}{c|}{\textbf{SSIM}} & \multicolumn{3}{c|}{\textbf{IoU/F1}} \\ \hline
\textbf{Model} & \multicolumn{1}{l|}{\textbf{Max.}} & \multicolumn{1}{l|}{\textbf{Mean}} & \textbf{Min.} & \textbf{Max.} & \textbf{Mean} & \textbf{Min.} \\ \hline
\textbf{EfficientNetB7} & \textbf{0.956} & \textbf{0.877} & \textbf{0.761} & \textbf{0.988} & \textbf{0.952} & \textbf{0.897} \\ \hline
InceptionV3 & 0.944 & 0.863 & 0.758 & 0.977 & 0.947 & 0.894 \\ \hline
InceptionResNetV2 & 0.941 & 0.859 & 0.743 & 0.983 & 0.943 & 0.886 \\ \hline
DenseNet201 & 0.940 & 0.862 & 0.747 & 0.978 & 0.945 & 0.891 \\ \hline
\end{tabular}
\caption{Evaluation of the state-of-the-art models. EfficientNetB7 is proven to be the most suitable model with a high SSIM and IoU score.}
\label{tab:evaluation_models}
\end{table}

\end{document}

Personally, I would suggest to use a different approach omitting all vertical and most horizontal lines, replacing the few useful, horizontal lines with the ones from the booktabs package for improved spacing and at the same time getting rid of the \textbf commands. Highlighting all column headers does not really seem to make sense here. In order to align the numbers inside of their cells with respect to the decimal marker, I also used an S column type from the siunitx package. (For this particular table, a simple c column would also work just as well). You can also combine this approach with tabular* is you nevertheless want to make sure the table is as wide as the textwidth while not dirtorting font sizes:

\documentclass{article}

\usepackage{booktabs}
\usepackage{siunitx}

\begin{document}
\begin{table}[ht]
\caption{Evaluation of the state-of-the-art models. EfficientNetB7 is proven to be the most suitable model with a high SSIM and IoU score.}
\label{tab:evaluation_models}
\centering
\begin{tabular}{l*{6}{S[table-format=1.4]}}
\toprule
& \multicolumn{6}{c}{Metric} \\  
\cmidrule{2-7}
 & \multicolumn{3}{c}{SSIM} & \multicolumn{3}{c}{IoU/F1} \\ 
 \cmidrule(r){2-4} \cmidrule(l){5-7}
Model & {Max.} & {Mean} & {Min.} & {Max.} & {Mean} & {Min.} \\
\midrule
EfficientNetB7 & 0.956 & 0.877 & 0.761 & 0.988 & 0.952 & 0.897 \\ 
InceptionV3 & 0.944 & 0.863 & 0.758 & 0.977 & 0.947 & 0.894 \\ 
InceptionResNetV2 & 0.941 & 0.859 & 0.743 & 0.983 & 0.943 & 0.886 \\ 
DenseNet201 & 0.940 & 0.862 & 0.747 & 0.978 & 0.945 & 0.891 \\ 
\bottomrule
\end{tabular}
\end{table}


\begin{table}[ht]
\caption{Evaluation of the state-of-the-art models. EfficientNetB7 is proven to be the most suitable model with a high SSIM and IoU score.}
\label{tab:evaluation_models}
\begin{tabular*}{\textwidth}{@{\extracolsep{\fill}}l*{6}{S[table-format=1.4]}}
\toprule
& \multicolumn{6}{c}{Metric} \\ 
\cmidrule{2-7}
 & \multicolumn{3}{c}{SSIM} & \multicolumn{3}{c}{IoU/F1} \\ 
 \cmidrule(r){2-4}   \cmidrule(l){5-7}
Model & {Max.} & {Mean} & {Min.} & {Max.} & {Mean} & {Min.} \\
\midrule
EfficientNetB7 & 0.956 & 0.877 & 0.761 & 0.988 & 0.952 & 0.897 \\ 
InceptionV3 & 0.944 & 0.863 & 0.758 & 0.977 & 0.947 & 0.894 \\ 
InceptionResNetV2 & 0.941 & 0.859 & 0.743 & 0.983 & 0.943 & 0.886 \\ 
DenseNet201 & 0.940 & 0.862 & 0.747 & 0.978 & 0.945 & 0.891 \\ 
\bottomrule
\end{tabular*}
\end{table}
\end{document}