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这个算法的结构是怎样的？

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这个算法的结构是怎样的？

我想要输入这个：

在此处输入图片描述

我开始这样做

\begin{subequations}
\begin{equation}
0. \text{la la la } 0 + 1 = 1
\end{equation
\begin{equation}
1. he he he 
\end{equation}
\end{subequations

但我认为这不是一个好方法。

该算法的结构是怎样的？

答案1

适合老人的工作tabbing：

\documentclass{article}

\usepackage{amsmath,amsthm}

\newtheoremstyle{mystyle}%  <name>
  {\topsep}%                <space above>
  {\topsep}%                <space below>
  {\normalfont}%            <body font>
  {}%                       <indent amount>
  {\bfseries}%              <theorem head font>
  {}%                       <punctuation after theorem head>
  {.5em}%                   <space after theorem head>
  {}%                       <theorem head spec>

\theoremstyle{mystyle}
\newtheorem{algorithm}{Algorithm}[section]

\newcommand{\algoqed}{%
  \makebox[0pt][l]{%
    \makebox[\textwidth][r]{\rule{0.4em}{0.7em}}%
  }%
}

\newcounter{algostep}
\newlength{\stepwidth}
\newcommand{\step}{%
  \refstepcounter{algostep}%
  \makebox[\stepwidth][r]{\thealgostep. }%
}
\newcommand{\initialstep}[2][1]{%
  \setcounter{algostep}{#2}%
  \addtocounter{algostep}{-1}%
  \settowidth{\stepwidth}{#1. }%
}

\begin{document}

\setcounter{section}{6}   %just for the example
\setcounter{algorithm}{1} %just for the example

\begin{algorithm}
\initialstep[10]{0}
The Preconditioned Conjugate Gradient Method for Solving the Symmetric 
Positive Definite System $Ax = b$, Starting with $x^{(0)}$
\begin{tabbing}
\step
  \= Input stopping criteria, $\epsilon$ and $k_{\text{max}}$.\\
  \> Set $k=0$, $r^{(k)}=b-Ax^{(k)}$, $s=Ar^{(k)}$, 
     $p=M^{-1}s^{(k)}$, $y^{(k)}=M^{-1}r^{(k)}$\\
  \> and $\gamma^{(k)}=y^{(k)\mathrm{T}}s^{(k)}$.\\
\step\label{step1}
  \> If $\gamma^{(k)}\le\epsilon$, set $x=x^{(k)}$ and terminate.\\
\step
  \> Set $q^{(k)}=Ap^{(k)}$.\\
\step
  \> Set $\alpha^{(k)}=\frac{\gamma^{(k)}}{\|q^{(k)}\|^2}$.\\
\step
  \> Set $x^{(k+1)}=x^{(k)}+\alpha^{(k)}p^{(k)}$.\\
\step
  \> Set $r^{(k+1)}=r^{(k)}-\alpha^{(k)}q^{(k)}$.\\
\step
  \> Set $s^{(k+1)}=A^{(k+1)}$.\\
\step
  \> Set $y^{(k+1)}=M^{-1}r^{(k+1)}$.\\
\step
  \> Set $\gamma^{(k+1)}=y^{(k+1)\mathrm{T}}s^{(k+1)}$.\\
\step
  \> Set $p^{(k+1)}=M^{-1}s^{(k+1)}+\frac{\gamma^{(k+1)}}{\gamma^{(k)}}p^{(k)}$.\\
\step
  \> If \= $k<k_{\text{max}}$,\\
  \>    \> set $k\gets k + 1$ and go to step \ref{step1};\\
  \> otherwise\\
  \>    \> issue message that\\
\algoqed
  \>    \> ``algorithm did not converge in $k_{\text{max}}$ iterations''.
\end{tabbing}
\end{algorithm}

\end{document}

用\initialstep[<final>]{<initial>}1 来设置初始和最终步骤数（实际上<final>仅用于数字位数，默认为 1）。算法中的步骤由 引入，\step后面可以跟\label。第一个\step后面是\=设置制表位。

最后一行可以加上\algoqed黑框作为前缀。

我会避免使用粗体字样；标题足以突出它。我保留了原来的大写字母，但它确实很难看。

在此处输入图片描述

答案2

恕我直言，它是用这样的方法完成的

\documentclass{article}

\usepackage{amsmath,amsthm,enumitem}

\newtheoremstyle{mystyle}%  <name>
  {\topsep}%                <space above>
  {\topsep}%                <space below>
  {\bfseries}%              <body font>
  {}%                       <indent amount>
  {\bfseries}%              <theorem head font>
  {}%                       <punctuation after theorem head>
  {.5em}%                   <space after theorem head>
  {}%                       <theorem head spec>

\theoremstyle{mystyle}
\newtheorem{algorithm}{Algorithm}[section]
\renewcommand{\qedsymbol}{\rule{0.4em}{0.7em}}

\setlist[enumerate]{%
  parsep=0pt,
  leftmargin=1.25\parindent,
  listparindent=\parindent
  }

\begin{document}

\setcounter{section}{6}   %just for the example
\setcounter{algorithm}{1} %just for the example

\begin{algorithm}
  The Preconditioned Conjugate Gradient Method for Solving the Symmetric 
  Positive Definite System $Ax = b$, Starting with $x^{(0)}$
\end{algorithm}
\begin{enumerate}
  \setcounter{enumi}{-1}
  \item Input stopping criteria, $\epsilon$ and $k_{\text{max}}$.\\
  Set...
  \item ...
  \setcounter{enumi}{9}   %just for the example
  \item If $k<k_{\text{max}}$,\\
  \indent set k = k + 1 and go to step 1;\\
  otherwise\\
  \indent issue message that\\
  \indent ``algorithm did not converge in $k_{\text{max}}$ iterations''.\qed
\end{enumerate}

\end{document}

在此处输入图片描述

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