# Undefined control sequence \State \COMMENT

Undefined control sequence \State \COMMENT.

The manual clearly state that I can use the \comment. I use \usepackage{algpseudocode} \usepackage{algorithm}. Here is my code:

\documentclass[10pt, a4paper]{article}
\usepackage[utf8x]{inputenc}
\usepackage{amsmath,graphicx,subfigure}

\title{{Bachelor Thesis\\[0.5em]}
{\bf \huge Road Inventory\\Detection and Recognition\\[0.5em]}
{\bf Weekly Report 3}}
\author{Poul Sørensen. s093294}

%\setlength{\parindent}{0mm}
\setlength{\parskip}{1.5mm}

\usepackage{lettrine}
\usepackage[draft,english]{fixme}                   %Pakke til at skrive marginnoter under arbejdet. Skift draft til final når der skal printes. Brug 'fxnote{}','fxwarning', 'fxerror' eller 'fxfatal' alt efter behov.
%\fxsetup{layout=margin}                            %Footnote anbefales som option - men er ikke specielt praktisk?

\newcommand{\openCV}{\texttt{OpenCV}~}
\newcommand{\cpp}{\texttt{C++}~}
\usepackage{url}

% Different font in captions
\usepackage[font=small,format=plain,labelfont=bf,up,textfont=it,up,margin=7mm]{caption}

\usepackage{multirow}
\usepackage{array}

\usepackage{rotating}

\renewcommand{\topfraction}{0.85}
\renewcommand{\textfraction}{0.1}
\renewcommand{\floatpagefraction}{0.75}

\usepackage{color}

\definecolor{quotationcolour}{rgb}{0.95,0.95,0.95}
\definecolor{quotationmarkcolour}{rgb}{0,0.4,0.9}
% Double-line for start and end of epigraph.
\newcommand{\epiline}{\hrule \vskip -.2em \hrule}
% Massively humongous opening quotation mark.
\newcommand{\hugequote}{%
\fontsize{42}{48}\selectfont \color{quotationmarkcolour} \textbf{}
\vskip -.5em
}

\newcounter{quotecounter}

% Beautify quotations.
\newcommand{\epigraph}[2]{%
\refstepcounter{quotecounter}
\begin{flushright}
\colorbox{quotationcolour}{%
\parbox{.95\textwidth}{%
\epiline \vskip 1em {\hugequote} \vskip -.5em
\parindent 2.2em
#1\begin{flushright}\textbf{Quote \thesection.\thequotecounter}~~ \textsc{#2}\end{flushright}
\epiline
}
}
\end{flushright}

}

\usepackage{algpseudocode}
\usepackage{algorithm}
\usepackage{eqparbox}
%\usepackage{program}
%\renewcommand{\algorithmiccomment}[1]{\hfill\eqparbox{COMMENT}{\backslash\backslash #1}}

\begin{document}

\maketitle

\newpage
\section{Performance Measurement }
There exist a few methods for measure performance~\cite{Book:OpenCV}. First one of interest is \textit{cross-validation} and its close related technique of \textit{bootstrapping}. A great outline on the topic can be found online\footnote{www.faqs.org/fags/ai-fag/neural-nets/part3/section-12.html}.

Cross-validation involves splitting the data $\Phi$ into $k$ distinct subsets ${\Phi_1,\cdots,\Phi_{k-1},\Phi_k}$, training $k$ times on $k-1$ of the subsets and testing with left out set. The $k$ test results can then be averaged to a final score.

%\begin{algorithm}
\begin{algorithmic}

\Procedure{CrossValidate}{$\Phi$}
\ForAll{$\phi \in {\Phi_1,\cdots,\Phi_{k-1},\Phi_k}$}
\State $model =$ Train($\Phi \setminus \phi$ )
\ForAll{$s \in \phi$ }
\State  \COMMENT{hej}
\EndFor

\EndFor
\EndProcedure

\end{algorithmic}
%\end{algorithm}

\section{Related Work}\fxnote{(intended for report.)}

\subsection{Machine Learning}
\input{../../"Report Parts"/MachineLearning/ML.tex}
\subsubsection{Prediction Trees}
\input{../../"Report Parts"/MachineLearning/PredictionTrees.tex}

\subsection{Colour Analysis}

\subsection{Decision Tree}

\subsection{Forest of Decision Trees}

\subsection{Hough Forest}

\newpage

\section*{Project status according to the study plan}

All under control. Report work is doing well.

\bibliographystyle{plain}
\bibliography{../../../../references}

\appendix
\end{document}

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Yes it is needed; you should give a minimal example. – jon Mar 5 '12 at 4:42
Code examples should be minimal, not as lengthy as yours. – Werner Mar 5 '12 at 6:18
Please don't do cross-site posts. Moderators can migrate questions from stackoverflow to tex.se – Thorsten Mar 5 '12 at 13:21

LaTeX is case sensitive it terms of control sequences. So, \Comment is different from \COMMENT, \comment and all other valid combinations. This is what you're after in terms of showing a comment - using \Comment{...}:

\documentclass{article}
\usepackage{algpseudocode}% http://ctan.org/pkg/algorithmicx
\begin{document}
\begin{algorithmic}
\Procedure{CrossValidate}{$\Phi$}
\ForAll{$\phi \in {\Phi_1,\cdots,\Phi_{k-1},\Phi_k}$}
\State $model =$ Train($\Phi \setminus \phi$ )
\ForAll{$s \in \phi$ }
\State \Comment{hej}
\EndFor
\EndFor
\EndProcedure
\end{algorithmic}
\end{document}


From the algorithmicx documentation (section 2.4 Placing comments in sources, p 4):

Comments may be placed everywhere in the source using the \Comment macro ...

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Somehow i got some manuals mixed up. \COMMENT was from program package. – s093294 Mar 5 '12 at 19:09
Thank you. It solve the issue – s093294 Mar 5 '12 at 19:09

I would like to add one more thing which is also helpful. sometimes you need to specify the place of your comment. so on the top of document

\newcommand{\Comment}[1]{{\hskip3em$\rightarrow$ #1}}


and inside the algorithm you could easily use

\Comment


and the results will appear like this

x → Here is a comment

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