bmc-maths.sty

%══════════════════════════════════════════%
%                                          %
%                  BMC                     %
%     A Bespoke, Multipurpose Class        %
%        -- Maths Functionality --         %
%                 -~=~-                    %
%          Authored by tecosaur            %
%                                          %
%══════════════════════════════════════════%

\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{bmc-maths}[2019/06/09 Maths functionality used in the BMC class]

\newif\ifbmc@nomathsfont
\newif\ifbmc@plainmathsdd
\bmc@nomathsfontfalse
\bmc@plainmathsddfalse
\DeclareOption{nofont}{\bmc@nomathsfonttrue}
\DeclareOption{plaindd}{\bmc@plainmathsddtrue}
\ProcessOptions\relax

% various math packages
\RequirePackage{amsmath,amssymb}
\ifbmc@nomathsfont\else
  \RequirePackage[varbb]{newpxmath}
\fi
\RequirePackage{xfrac}
\RequirePackage[makeroom]{cancel}
\RequirePackage{mathtools}

% deliminators
\DeclarePairedDelimiter{\abs}{\lvert}{\rvert}
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}

\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
\DeclarePairedDelimiter{\floor}{\lfloor}{\rfloor}
\DeclarePairedDelimiter{\round}{\lfloor}{\rceil}
% number sets
\newcommand{\RR}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{R}}{\mathbb{R}^{#1}}}}
\newcommand{\NN}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{N}}{\mathbb{N}^{#1}}}}
\newcommand{\ZZ}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{Z}}{\mathbb{Z}^{#1}}}}
\newcommand{\QQ}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{Q}}{\mathbb{Q}^{#1}}}}
\newcommand{\CC}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{C}}{\mathbb{C}^{#1}}}}
\newcommand{\PP}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{P}}{\mathbb{P}^{#1}}}}
\newcommand{\HH}[1][]{\ensuremath{\ifstrempty{#1}{\mathbb{H}}{\mathbb{H}^{#1}}}}
% expected value
\newcommand{\EE}{\ensuremath{\mathbb{E}}}

% commonly used macros
%  - differentials
\ifbmc@plainmathsdd
  \newcommand{\dd}[1][]{\ensuremath{\,\mathsl{d}^{#1}}}
\else
  \newsavebox\diffdbox
  \newcommand{\slantedromand}{{\mathpalette\makesl{d}}}
  \newcommand{\makesl}[2]{%
    \begingroup
    \sbox{\diffdbox}{$\mathsurround=0pt#1\mathrm{#2}$}%
    \pdfsave
    \pdfsetmatrix{1 0 0.2 1}%
    \rlap{\usebox{\diffdbox}}%
    \pdfrestore
    \hskip\wd\diffdbox
    \endgroup
  }
  \newcommand{\dd}[1][]{\ensuremath{\mathop{}\!\ifstrempty{#1}{%
        \slantedromand\@ifnextchar^{\hspace{0.2ex}}{\hspace{0.1ex}}}%
      {\slantedromand\hspace{0.2ex}^{#1}}}}
\fi
\ProvideDocumentCommand\dv{o m g}{%
  \ensuremath{%
    \IfValueTF{#3}{%
      \IfNoValueTF{#1}{%
        \frac{\dd #2}{\dd #3}%
      }{%
        \frac{\dd^{#1} #2}{\dd #3^{#1}}%
      }%
    }{%
      \IfNoValueTF{#1}{%
        \frac{\dd}{\dd #2}%
      }{%
        \frac{\dd^{#1}}{\dd #2^{#1}}%
      }%
    }%
  }%
}
\providecommand*{\pdv}[3][]{\frac{\partial^{#1}#2}{\partial#3^{#1}}}
%  - others
\DeclareMathOperator{\Lap}{\mathcal{L}}
\DeclareMathOperator{\Var}{Var} % varience
\DeclareMathOperator{\Cov}{Cov} % covarience
\DeclareMathOperator{\E}{E} % expected

% Since the amsthm package isn't loaded
\newcommand*{\qed}{\hfill\ensuremath{\blacksquare}}
\newcommand*{\qedhere}{\hfill\ensuremath{\square}}

% I prefer the slanted \leq
\let\oldleq\leq % save them in case they're every wanted
\let\oldgeq\geq
\renewcommand{\leq}{\leqslant}
\renewcommand{\geq}{\geqslant}

% redefine matrix env to allow for alignment, use r as default
\renewcommand*\env@matrix[1][r]{\hskip -\arraycolsep
    \let\@ifnextchar\new@ifnextchar
    \array{*\c@MaxMatrixCols #1}}