Hspace* does vertical space instead of horizontal space in algorithm block

algorithmicxhorizontal alignment

I tried to use the algorithmic package to write down a pseudo code.

\begin{algorithm}
   \caption{caption}
   \Require $n\in \N$, fixed time $T>0$
   \begin{algorithmic}[1]
        \State T        
   \end{algorithmic}
\end{algorithm}

Then I get the following output:

So I tried adding the indent at Require so that it starts on a line with the rest and therefore I used the solution of this post (How to add input and output before algorithm procedure) and added \hspace*{\algorithmicindent}, i.e.

\begin{algorithm}
    \caption{caption}
    \hspace*{\algorithmicindent} \Require $n\in \N$, fixed time $T>0$
    \begin{algorithmic}[1]
        \State T
    \end{algorithmic}
\end{algorithm}

But instead of horizontal indent i get vertical indent:

Since I don't get any error message either, I'm a bit lost as to why it misinterprets the command like that. Does anyone know what is going wrong here? Thanks in advance!

Best Answer

Presumably Require is starting a new paragraph so your \hspace* is not making vertical space it is making a single line paragraph with just a horizontal space

You would see the same if you used \hspace* before \section or \begin{quote}

Related Solutions

[Tex/LaTex] Algorithm and IEEEtran

The IEEEtran's documentation suggests:

B. Algorithms

IEEE publications use the figure environment to contain algorithms that are not to be a part of the main text flow. Peter Williams’ and Rogerio Brito’s algorithmic.sty package [24] or Szász János’ algorithmicx.sty package [25] (the latter is designed to be more customizable than the former) may be of help in producing algorithm-like structures (although authors are of course free to use whatever LaTeX commands they are most comfortable with in this regard). However, do not use the floating algorithm environment of algorithm.sty (also by Williams and Brito) or algorithm2e.sty (by Christophe Fiorio) as the only floating structures IEEE uses are figures and tables. Furthermore, IEEEtran will not be in control of the (non-IEEE) caption style produced by the algorithm.sty or algorithm2e.sty float environments.

So, as suggested, do not use the algorithm floating environment; you can wrap your algorithm inside a figure (or figure*) environment (if a caption is required and the captions are to be IEEEtran compliant) and use the algorithmicx package ; something like this:

\documentclass{IEEEtran}
\usepackage{algpseudocode}

\begin{document}

\begin{figure}
\begin{algorithmic}[1]
\Procedure{Euclid}{$a,b$}\Comment{The g.c.d. of a and b}
\State $r\gets a\bmod b$
\While{$r\not=0$}\Comment{We have the answer if r is 0}
\State $a\gets b$
\State $b\gets r$
\State $r\gets a\bmod b$
\EndWhile\label{euclidendwhile}
\State \textbf{return} $b$\Comment{The gcd is b}
\EndProcedure
\end{algorithmic}
\caption{Euclid's algorithm}\label{euclid}
\end{figure}

\end{document}

enter image description here

If no caption is required, then simply don't use the figure environment.

[Tex/LaTex] Algorithm as figure and without italic and bold formatting

Is this what you are trying to achieve?

enter image description here

This is the MWE:

\documentclass{article}
\usepackage[plain]{algorithm}
\usepackage{algpascal}

\begin{document}

\algrenewcommand\textkeyword{\textrm}
\algdef{SE}{For}{End}[2]{%
  \textkeyword{for} \(#1\) \textkeyword{to} \(#2\) \textkeyword{do begin}}{%
  \textkeyword{end}}

\begin{algorithm}
\begin{algorithmic}[1]
\State Assign an ordering $A_{1}, ..., A_{n}$ to the nonterminals of the grammar.
\For{i = 1}{n}
    \For{j = 1}{i-1}
    \State for each production of the form $A_{i} \rightarrow A_{j} \alpha$
    \End
\End
\end{algorithmic}
\caption{Paull's algorithm}
\end{algorithm}

\end{document}

Explanation

To match your first two requests, I've redefined the behavior of for to have an end statement by adding the lines:

\algdef{SE}{For}{End}[2]{%
  \textkeyword{for} \(#1\) \textkeyword{to} \(#2\) \textkeyword{do begin}}{%
  \textkeyword{end}}

To match your last request, it suffices to add the line:
```
\algrenewcommand\textkeyword{\textrm}
```
which redefines the font for keywords to be \textrm instead of \textbf.
In regards of your 3rd request, there are two ways.
- If you want the algorithm to behave as an algorithm, simply load the algorithm package with the option plain as in the above MWE:
```
\usepackage[plain]{algorithm}
```
- If you want the algorithm to behave as a figure, there is no need to load the algorithm package, simply insert the algorithmic environment inside a figure, i.e. replace the lines
```
\begin{algorithm}
\begin{algorithmic}[1]
...
\end{algorithmic}
\caption{Paull's algorithm}
\end{algorithm}
```
  with
```
\begin{figure}
\begin{algorithmic}[1]
...
\end{algorithmic}
\caption{Paull's algorithm}
\end{figure}
```
  and you will have

Addendum

This is the complete implementation of the algorithm in the figure:

\documentclass{article}
\usepackage[plain]{algorithm}
\usepackage{algpascal}

\begin{document}

\algrenewcommand\textkeyword{\textrm}
\algdef{SE}{For}{End}[2]{%
  \textkeyword{for} \(#1\) \textkeyword{to} \(#2\) \textkeyword{do begin}}{%
  \textkeyword{end}}
\algdef{SE}{ForEach}{End}[1]{%
  \textkeyword{for each} #1 \textkeyword{do begin}}{%
  \textkeyword{end}}

\begin{algorithm}
\begin{algorithmic}[1]
\State Assign an ordering $A_{1}, \dots, A_{n}$ to the nonterminals of the grammar.
\For{i := 1}{n}
    \For{j := 1}{i-1}
        \ForEach{production of the form $A_{i} \rightarrow A_{j} \alpha$}
            \State remove $A_{i} \rightarrow A_{j} \alpha$ from the grammar
            \ForEach{production of the form $A_{j} \rightarrow \beta$}
                \State add $A_{i} \rightarrow \beta\alpha$ to the grammar
            \End
        \End
    \End
    \State transform the $A_{i}$-productions to eliminate direct left recursion
\End
\end{algorithmic}
\caption{Paull's algorithm}
\end{algorithm}

\end{document}

enter image description here

There is the need to define a new command \ForEach:

\algdef{SE}{ForEach}{End}[1]{%
  \textkeyword{for each} #1 \textkeyword{do begin}}{%
  \textkeyword{end}}

Note that I've defined \ForEach so to take one "text" argument, because it seemed to me the best way to define it.

If you want it to take a "math" argument, then define it as

\algdef{SE}{ForEach}{End}[1]{%
  \textkeyword{for each} \(#1\) \textkeyword{do begin}}{%
  \textkeyword{end}}

and use it as follows (amsmath is needed for the command \text):

\ForEach{\text{production of the form }A_{i} \rightarrow A_{j} \alpha}

Best Answer

Related Solutions

[Tex/LaTex] Algorithm and IEEEtran

[Tex/LaTex] Algorithm as figure and without italic and bold formatting

Explanation

Addendum

Related Question