Achieving captioning with align blocks

Question

I have code like this:

\begin{align}
  c_{i,p} = \frac{c_{i,p}}{IQR(c_{i})}\label{eq:1}\\  
  c_{i,p} = \frac{c_{i,p})}{Median(c_{i})}\label{eq:1}\\  
  c_{i,p} = \frac{c_{i,p})}{MAD(c_{i})}\label{eq:1}\\  
  c_{i,p} = \frac{c_{i,p})}{max(c_{i,p})-c_{i,p}}\label{eq:1}\\  
  c_{i,p} = \frac{c_{i,p})}{max(c_{i,p})-c_{i,p}}\label{eq:1}\\  
\end{align}

That looks like:

However, I came across the formatting of this textbook like so and would love to add captions in this way. There are two types of ways the author captions the formulas.

1. Each formula is in a block grid and each has a label between (1) to (3). I want to achieve this and also allow captioning around the whole figure created so that it goes in my \listoffigures.

2. Each formula has its own subsubsection number. I want to achieve this too or at least see how it is done.

Answer 1

Some comments:

• What you call "captions" of equations appear to be, in LaTeX jargon, nothing but \paragraph-level headers. To wit, it's straightforward to replicate the "look" of your textbook using \paragraph instructions; see also the code below.

• Use of the \paragraph approach provides a high degree of flexibility of where page breaks may occur. With an align-based approach, you'd have to worry about where to allow page breaks.

• In your textbook excerpt, the equations do not appear to be aligned relative to each other. Put differently, they are individually and independently centered on their respective lines. I suggest you use individual equation environments.

Aside: Since "IQR", "MAD", and "Median" would appear to be operators (in the TeX/LaTeX sense of the word), they should be typeset in upright letters. The amsmath package lets you create math operators via the \DeclareMathOperator directive. By the way, \max is already defined -- use it!

\documentclass{article}
\setcounter{secnumdepth}{4} % default is "3" for article document class
% Paragraph-level headers: italic, not bold
\usepackage{sectsty}
\paragraphfont{\mdseries\itshape} 

\usepackage{amsmath} % for \DeclareMathOperator and \numberwithing macros
\DeclareMathOperator{\IQR}{IQR}
\DeclareMathOperator{\Median}{Median}
\DeclareMathOperator{\MAD}{MAD}
\numberwithin{equation}{section}

\begin{document}
% Just for this example:
\setcounter{section}{2}
\setcounter{subsection}{2}
\setcounter{subsubsection}{23}
\setcounter{equation}{36}

\paragraph{Interquartile range}
\begin{equation}
  c_{i,p} = \frac{c_{i,p}}{\IQR(c_{i})}\label{eq:1}
\end{equation}
\paragraph{Median}
\begin{equation} 
  c_{i,p} = \frac{c_{i,p}}{\Median(c_{i})}\label{eq:2}
\end{equation}
\paragraph{Minimum absolute distance}
\begin{equation} 
  c_{i,p} = \frac{c_{i,p}}{\MAD(c_{i})}\label{eq:3}
\end{equation}
\paragraph{Max 1}
\begin{equation} 
  c_{i,p} = \frac{c_{i,p}}{\max(c_{i,p})-c_{i,p}}\label{eq:4} 
\end{equation}
\paragraph{Max 2}
\begin{equation} 
  c_{i,p} = \frac{c_{i,p}}{\max(c_{i,p})-c_{i,p}}\label{eq:5}  
\end{equation}
\end{document}