Latex 算法怎么写？（一）：algorithm, algorithmic算法包到底什么区别？

June 01, 2020

2020   ·   techniques     ·   techniques  

原文: http://zhuanlan.zhihu.com/p/145195565

原文： https://tex.stackexchange.com/questions/229355/algorithm-algorithmic-algorithmicx-algorithm2e-algpseudocode-confused

概括版本

  • algorithm - float wrapper for algorithms.
  • algorithmic - first algorithm typesetting environment.
  • algorithmicx - second algorithm typesetting environment.
  • algpseudocode - layout for algorithmicx.
  • algorithm2e - third algorithm typesetting environment.

我结合algpseudocode使用algorithmicx，因为他们比algorithmic高级。另外algorithmicx提供了和algorithm2e相同的功能，但是它的语法更加简洁易懂。

絮絮叨叨版本

1. algorithm

algorithm是 算法的float warpper，类似于table, figure这样的们命令，你可以在你的表格/图形上加一个数字，防止它被分成两页。官方文档说明如下：

When placed within the text without being encapsulated in a floating environment algorithmic environments may be split over a page boundary, greatly detracting from their appearance. In addition, it is useful to have algorithms numbered for reference and for lists of algorithms to be appended to the list of contents. The algorithm environment is meant to address these concerns by providing a floating environment for algorithms.

例子

\begin{algorithm}
    \caption{Algorithm caption}
    \label{alg:algorithm-label}
    \begin{algorithmic}
        ... Your pseudocode ...
    \end{algorithmic}
\end{algorithm}

2. algorithmic

事先已经定义好一些常用的命令语句，有如IF,WHILE等。需要注意的是所有命令语句必须大写。官方文档说明如下：

The algorithmic environment provides an environment for describing algorithms and the algorithm environment provides a “float” wrapper for algorithms (implemented using algorithmic or some other method at the users’s option). The reason for two environments being provided is to allow the user maximum flexibility.

3. algorithmicx

这个可以理解成algorithmic的升级版，他可以让我们自定义一些命令，这个是algorithmic没有的功能。如果你不需要自定义命令，使用algorithmic就好了。另外因为二者的语法很相似,只有部分语法和细节有略微差异，可见下面的例子。官方文档说明如下：

The package algorithmicx itself doesn’t define any algorithmic commands, but gives a set of macros to define such a command set. You may use only algorithmicx, and define the commands yourself, or you may use one of the predefined command sets

\begin{algorithm}
    \caption{Euclid’s algorithm}
    \label{euclid}
    \begin{algorithmic}[1] % The number tells where the line numbering should start
        \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}
\end{algorithm}

4. algpseudocode

这个其实就是algorithmicx的layout(不知道咋翻译。。)， 它试图尽可能类似于algorithmic。 还有其他layout，例如：

  • algcompatible(与algorithmic包完全兼容)，
  • algpascal(目标是创建一个格式化的Pascal程序，可以用一些基本的替换规则将Pascal程序转换成algpascal算法描述)。
  • algc(就像algpascal一样，但是为c语言设计的。）

官方文档说明如下：

If you are familiar with the algorithmic package, then you’ll find it easy to switch. You can use the old algorithms with the algcompatible layout, but please use the algpseudocode layout for new algorithms. To use algpseudocode, simply use \usepackage{algpseudocode}. You don’t need to manually load the algorithmicx package, as this is done by algpseudocode.

总的来说就是如果你要是用这个包，直接\usepackage{algpseudocode}就可以了,因为它会自动导入algorithmicx，然后语法直接用algorithmicx的语法就行了。

5. algorithm2e

这是另外一个和algorithmic和algorithmicx类似的算法包，官方文档说明如下：

Algorithm2e is an environment for writing algorithms in LaTeX2e. An algorithm is defined as floating object like figures. It provides macros that allow you to create different sorts of key words, thus a set of predefined key words is given. You can also change the typography of the keywords.

例子

\begin{algorithm}[H]
    \SetAlgoLined
    \KwData{this text}
    \KwResult{how to write algorithm with \LaTeX2e }
    initialization\;
    \While{not at end of this document}{
        read current\;
        \eIf{understand}{
            go to next section\;
            current section becomes this one\;
            }{
            go back to the beginning of current section\;
        }
    }
\caption{How to write algorithms}
\end{algorithm}

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2020-06-01 23:21:53

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