章节标题中的粗体数学符号

Question

我希望用数学模式写一封信，并在章节标题中以粗体显示。

运行这个

\documentclass[
    pdftex,a4paper,11pt,oneside,fleqn,
    bibliography=totoc,listof=totoc,
    headlines=2.1,headsepline,
    numbers=noenddot
]{scrreprt}

%%%----- PDF Format -----------------------------
\usepackage{float}
\usepackage[pdftex,pdfpagelabels,bookmarks,bookmarksopen,bookmarksnumbered,
    bookmarksopenlevel      = 1,
    pdfstartpage                    = 1,
    pdfstartview                    = FitV, 
    pdfpagelayout                   = SinglePage,
    plainpages                      = false,
    hypertexnames                   = false,
    colorlinks                      = true, 
    linkcolor                           = black,
    citecolor                           = black,
    urlcolor                            = black
]{hyperref}
    
%%%----- Mathe ----------------------------------
\usepackage{amsmath,amsfonts,amssymb,bm}
\usepackage[squaren,textstyle]{SIunits}
\usepackage{icomma}
    
\usepackage{mathtools}
\usepackage[makeroom]{cancel}
            
\begin{document}

\section{Filtered-$\boldsymbol{x}$-LMS (FxLMS)-Algorithmus}
blabla

\begin{align*}
    a \cdot b\\
    c {\cdot} d
\end{align*}

\end{document}

我收到以下错误： ! Illegal parameter number in definition of \BKM@title.

Answer 1

您显示的代码不会产生错误。但如果我添加

\usepackage{hyperref}
\usepackage{bookmark}

我确实

! Illegal parameter number in definition of \BKM@title.
<to be read again>
                   2
l.14 ...-$\boldsymbol{x}$-LMS (FxLMS)-Algorithmus}

问题是，在\boldsymbol书签制作过程中无法保存。标准的解决方法是

\section{Filtered-\texorpdfstring{$\boldsymbol{x}$}{x}-LMS (FxLMS)-Algorithmus}

完整代码：

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath,amsfonts,amssymb,bm}
\usepackage[squaren,textstyle]{SIunits}
\usepackage{icomma}

\usepackage{mathtools}
\usepackage[makeroom]{cancel}
\usepackage{hyperref}
\usepackage{bookmark}

\begin{document}

\section{Filtered-\texorpdfstring{$\boldsymbol{x}$}{x}-LMS (FxLMS)-Algorithmus}
blabla

\end{document}

几点说明。

由于有些年份，\usepackage[utf8]{inputenc}可以省略。

该软件包SIunits很旧，并且无人维护。您应该切换到siunitx功能更强大、维护和开发更完善的软件包。

您可以使用\bm代替\boldsymbol：它更短。

Answer 2

由于您使用的是 Koma-Script 类（scrreprt），您可以通过在序言中添加此行来使章节标题中的所有数学内容变为粗体：

\addtokomafont{sectioning}{\boldmath}

因此，修改后的 MWE：

\documentclass[
    pdftex,a4paper,11pt,oneside,fleqn,
    bibliography=totoc,listof=totoc,
    headlines=2.1,headsepline,
    numbers=noenddot
]{scrreprt}

%%%----- PDF Format -----------------------------
\usepackage{float}
\usepackage[pdftex,pdfpagelabels,bookmarks,bookmarksopen,bookmarksnumbered,
    bookmarksopenlevel      = 1,
    pdfstartpage                    = 1,
    pdfstartview                    = FitV, 
    pdfpagelayout                   = SinglePage,
    plainpages                      = false,
    hypertexnames                   = false,
    colorlinks                      = true, 
    linkcolor                           = black,
    citecolor                           = black,
    urlcolor                            = black
]{hyperref}
    
%%%----- Mathe ----------------------------------
\usepackage{amsmath,amsfonts,amssymb,bm}
\usepackage[squaren,textstyle]{SIunits}
\usepackage{icomma}
    
\usepackage{mathtools}
\usepackage[makeroom]{cancel}

\addtokomafont{sectioning}{\boldmath}
            
\begin{document}

\section{Filtered-$x$-LMS (FxLMS)-Algorithmus}
blabla

\end{document}

这混合了衬线和无衬线字体，但您也可以更改字体sectioning，或选择粗体无衬线数学样式用于标题。

\documentclass[
    pdftex,a4paper,11pt,oneside,fleqn,
    bibliography=totoc,listof=totoc,
    headlines=2.1,headsepline,
    numbers=noenddot
]{scrreprt}

%%%----- PDF Format -----------------------------
\usepackage{float}
\usepackage[pdftex,pdfpagelabels,bookmarks,bookmarksopen,bookmarksnumbered,
    bookmarksopenlevel      = 1,
    pdfstartpage                    = 1,
    pdfstartview                    = FitV, 
    pdfpagelayout                   = SinglePage,
    plainpages                      = false,
    hypertexnames                   = false,
    colorlinks                      = true, 
    linkcolor                           = black,
    citecolor                           = black,
    urlcolor                            = black
]{hyperref}
    
%%%----- Mathe ----------------------------------
\usepackage{amsmath,amsfonts,amssymb,bm}
\usepackage[squaren,textstyle]{SIunits}
\usepackage{icomma}
    
\usepackage{mathtools}
\usepackage[makeroom]{cancel}

\DeclareMathVersion{boldsans}
\SetSymbolFont{operators}{boldsans}{OT1}{cmsmf} {bx}{n}
\SetSymbolFont{letters}  {boldsans}{OML}{cmssm} {b}{it}
\SetSymbolFont{symbols}  {boldsans}{OMS}{cmsssy}{b}{n}
\SetSymbolFont{largesymbols}{boldsans}{OMX}{cmssex}{m}{n}

\addtokomafont{sectioning}{\mathversion{boldsans}}
            
\begin{document}

\section{Filtered-$x$-LMS (FxLMS)-Algorithmus}
    {\mathversion{boldsans}
    \[ \int \frac{\sqrt{\epsilon}}{x} \mathop{\mathrm{d}x}{} = \sqrt{\epsilon} \ln x + C
    \]
    }

\end{document}