[Tex/LaTex] Cleveref: Parentheses around references to subequations using \labelcref

amsmathcleverefcross-referencingequationssubequations

Using the Cleveref package (v0.19) i have a problem with missing parentheses when referencing to subequations, using the \labelcref command. Here is a MWE:

\documentclass{article}
\usepackage{parskip}
\usepackage{amsmath}
\usepackage{cleveref}

% Change so that the parentheses for equations are part of the hyperlink
\creflabelformat{equation}{#2(#1)#3}
\crefrangelabelformat{equation}{#3(#1)#4 to #5(#2)#6}

% This does not work:
\creflabelformat{subequations}{#2(#1)#3}
\crefrangelabelformat{subequations}{#3(#1)#4 to #5(#2)#6}

\begin{document}
\textbf{Writing three subequations:}
\begin{subequations}\label{eqn:abc}
    \begin{align}
        A&=B\label{eqn:abc1}\\
        B&=C\label{eqn:abc2}\\
        C&=A\label{eqn:abc3}
    \end{align}
\end{subequations}
Referencing using \texttt{$\backslash$cref}: \cref{eqn:abc}, \cref{eqn:abc1}, \cref{eqn:abc2}, \cref{eqn:abc3}.

Referencing using \texttt{$\backslash$labelcref}: \labelcref{eqn:abc}, \labelcref{eqn:abc1}, \labelcref{eqn:abc2}, \labelcref{eqn:abc3}. $\leftarrow$ Parenthesis are missing for subequations!\\[2ex]

\textbf{Writing two separate single equations:}
\begin{equation}\label{eqn:singlexy}
    x=y
\end{equation}
and
\begin{equation}\label{eqn:singleyx}
    y=x
\end{equation}
Referencing using \texttt{$\backslash$cref}: \cref{eqn:singlexy}, \cref{eqn:singleyx}.

Referencing using \texttt{$\backslash$labelcref}: \labelcref{eqn:singlexy}, \labelcref{eqn:singleyx}. $\leftarrow$ Parenthesis are \emph{not} missing for normal equations!
\end{document}

The output is as follows:

Output of MWE above

As can be seen, the \labelcref command omits the parentheses when referencing to the subequations (1a, 1b and 1c), as well as to their parent equation (1). As mentioned in the code above, the following lines of code do not solve the problem:

\creflabelformat{subequations}{#2(#1)#3}
\crefrangelabelformat{subequations}{#3(#1)#4 to #5(#2)#6}

I'm quite certain it worked in an earlier version of Cleveref (without adding the above two lines).

Any ideas would be greatly appreciated!

Best Answer

You are right, in version 0.18.9 the parenthesis were there.

In the latest version, additional support for subequations has been added. So says the documentation:

Added separate subequation cross-reference type

First of all, you have to use subequation instead of subequations and, for them, \labelcrefformat instead of \creflabelformat and \labelcrefrangeformat instead of \crefrangelabelformat, that is

\labelcrefformat{subequation}{#2(#1)#3}
\labelcrefrangeformat{subequation}{#3(#1)#4 to #5(#2)#6}

instead of

\creflabelformat{subequations}{#2(#1)#3}
\crefrangelabelformat{subequations}{#3(#1)#4 to #5(#2)#6}

MWE:

\documentclass{article}
\usepackage{parskip}
\usepackage{amsmath}
\usepackage[colorlinks]{hyperref}
\usepackage{cleveref}

% Change so that the parentheses for equations are part of the hyperlink
\creflabelformat{equation}{#2(#1)#3}
\crefrangelabelformat{equation}{#3(#1)#4 to #5(#2)#6}

% This does work:
\labelcrefformat{subequation}{#2(#1)#3}
\labelcrefrangeformat{subequation}{#3(#1)#4 to #5(#2)#6}

\begin{document}
\textbf{Writing three subequations:}
\begin{subequations}\label{eqn:abc}
    \begin{align}
        A&=B\label{eqn:abc1}\\
        B&=C\label{eqn:abc2}\\
        C&=A\label{eqn:abc3}
    \end{align}
\end{subequations}
Referencing using \texttt{$\backslash$cref}: \cref{eqn:abc}, \cref{eqn:abc1}, \cref{eqn:abc2}, \cref{eqn:abc3}.

Referencing using \texttt{$\backslash$labelcref}: \labelcref{eqn:abc}, \labelcref{eqn:abc1}, \labelcref{eqn:abc2}, \labelcref{eqn:abc3}. $\leftarrow$ Parenthesis are \emph{NOT} missing for subequations!\\[2ex]

\textbf{Writing two separate single equations:}
\begin{equation}\label{eqn:singlexy}
    x=y
\end{equation}
and
\begin{equation}\label{eqn:singleyx}
    y=x
\end{equation}
Referencing using \texttt{$\backslash$cref}: \cref{eqn:singlexy}, \cref{eqn:singleyx}.

Referencing using \texttt{$\backslash$labelcref}: \labelcref{eqn:singlexy}, \labelcref{eqn:singleyx}. $\leftarrow$ Parenthesis are \emph{not} missing for normal equations!
\end{document}

Output:

enter image description here

Strangely enough, for equations you have to use \creflabelformat and \crefrangelabelformat.

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[Tex/LaTex] flush text on the left and centre equation of the same line (not working!)

Here are three possibilities; the first two are variants based on the flalign environment, with a different positioning of the equations w.r.t.the left margin text. The third possibility paves the texts aligned w.r.t. each other, at some distance from the equations. It's based on alignat:

\documentclass[a4paper, 12pt, default, numbered, print, index]{article}
\usepackage{mathtools}

\usepackage{eqparbox} \newcommand{\eqmathbox}2[M]{\eqmakebox[#1]{$\displaystyle#2$}}

\DeclareFontFamily{U}{mathx}{\hyphenchar\font45}
\DeclareFontShape{U}{mathx}{m}{n}{
<5><6><7><8><9><10>
<10.95><12><14.4><17.28><20.74><24.88>
mathx10
}{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathAccent{\widebar}{0}{mathx}{"73}

\begin{document}

We can simplify our analysis by assuming the flow is inviscid ($\tau_{i,j}$ = 0), an ideal gas ($p = ρRT$), and calorically perfect ($c_p$, $c_v$ = constant). Thus, for a homogeneous, steady, uniform gas flow in a straight duct without heat conduction, the linearised governing equations can be written as:

\begin{subequations}
\begin{flalign}
\label{eq:linear_EOM_vector_mass}
 & \rlap{Mass} & &\eqmathbox{\frac{\widebar{D}\rho'}{Dt} + \bar{ρ}∇ · \boldsymbol{u}' = \mathbf{0}} & \\[0.8ex]
\label{eq:linear_EOM_vector_mom}
 & \rlap{Momentum} & &\eqmathbox{\frac{\widebar{D}\mathbf{u}'}{Dt} + \frac{1}{\bar{ρ}}
∇ p' = \mathbf{0}}
\end{flalign}
\end{subequations}

\begin{subequations}
\begin{flalign}
\label{eq:linear_EOM_vector_mass}
 & \text{Mass} & & \frac{\widebar{D}\rho'}{Dt} + \bar{ρ}∇ · \boldsymbol{u}' = \mathbf{0} &\hspace{12em} \\[0.8ex]
\label{eq:linear_EOM_vector_mom}
 & \text{Momentum} & & \frac{\widebar{D}\mathbf{u}'}{Dt} + \frac{1}{\bar{ρ}}
∇ p' = \mathbf{0}&&
\end{flalign}
\end{subequations}

\begin{subequations}
\begin{alignat}{2}
\label{eq:linear_EOM_vector_mass}
 & \text{Mass} &\hspace{3em} &\frac{\widebar{D}\rho'}{Dt} + \bar{ρ}∇ · \boldsymbol{u}' = \mathbf{0} \\[0.8ex]
\label{eq:linear_EOM_vector_mom}
 & \text{Momentum} & & \frac{\widebar{D}\mathbf{u}'}{Dt} + \frac{1}{\bar{ρ}}
∇ p' = \mathbf{0}
\end{alignat}
\end{subequations}

\end{document}

Edit: Here is how to adapt the first solution to the last version of the O.P.'s code (two variants):

\documentclass[a4paper,12pt,default,numbered,print,index]{article}
\usepackage{lipsum}
\usepackage{enumitem}
\usepackage{graphicx} % Required for the inclusion of images
\usepackage{setspace} % for use of \singlespacing and \doublespacing
\usepackage{pdfpages}
\usepackage{cite}
\usepackage[section]{placeins}
\usepackage{comment}
\usepackage{siunitx}
\usepackage{color}
\usepackage{ragged2e}
\usepackage{esvect}
\usepackage{mathtools}
\usepackage{lscape}
\usepackage{tabularx}
\usepackage{multirow}
\usepackage{array}
\usepackage{soul}
\usepackage{bm}
\usepackage{url}
\usepackage{xparse}
\usepackage{hyperref}
\newcommand{\myeqlabel}[1]{\rlap{\bfseries#1}}
\usepackage{eqparbox}
\newcommand{\eqmathbox}[2][M]{\eqmakebox[#1]{$\displaystyle#2$}}

    \DeclareFontFamily{U}{mathx}{\hyphenchar\font45}
    \DeclareFontShape{U}{mathx}{m}{n}{
    <5><6><7><8><9><10>
    <10.95><12><14.4><17.28><20.74><24.88>
    mathx10
    }{}
    \DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
    \DeclareFontSubstitution{U}{mathx}{m}{n}
    \DeclareMathAccent{\widebar}{0}{mathx}{"73}


\begin{document}

We can simplify our analysis by assuming the flow is inviscid ($\tau_{i,j} = 0$), an ideal gas ($p = \rho RT$), and calorically perfect ($c_p$, $c_v$ = constant). Thus, for a homogeneous, steady, uniform gas flow in a straight duct without heat conduction, the linearised governing equations can be written as:
\begin{subequations}
\begin{flalign}
& \myeqlabel{Mass} &&
    \eqmathbox{\frac{\widebar{D}\rho'}{Dt} + \bar{\rho}\,\nabla\cdot\boldsymbol{u}'
            = \mathbf{0}} & \label{eq:linear_EOM_vector_mass}\\
& \myeqlabel{Momentum} &&
    \eqmathbox{\frac{\widebar{D}\mathbf{u}'}{Dt} + \frac{1}{\bar{\rho}} \nabla p'
            = \mathbf{0}} & \label{eq:linear_EOM_vector_mom}\\
& \myeqlabel{Energy} && 
    \eqmathbox{c_p\frac{\widebar{D}}{Dt}(\bar{\rho}\,T' + \rho'\widebar{T}) + \nabla \cdot (\boldsymbol{u'}\bar{p} + \bar{\boldsymbol{u}}p')
            = \dot{q}'\bar{\rho} + \bar{\dot{q}}\rho' }& \label{eq:linear_EOM_vector_energy}\\
& \myeqlabel{Entropy} && 
    \eqmathbox{\frac{\widebar{D}s'}{Dt}
            = \frac{\dot{q}'}{\bar{\rho}\,\bar{T}}} & \label{eq:linear_EOM_vector_entropy}\\
& \myeqlabel{Vorticity} &&
    \eqmathbox{\frac{\widebar{D}\boldsymbol{\xi}'}{Dt}
            = \mathbf{0}} & \label{eq:linear_EOM_vector_vorticity}
\end{flalign}
\end{subequations}
\begin{subequations}
\begin{flalign}
& \myeqlabel{Mass} &&
    \eqmathbox{\frac{\widebar{D}\rho'}{Dt} + \bar{\rho}\,\nabla\cdot\boldsymbol{u}'
            = \mathbf{0}} & \label{eq:linear_EOM_vector_mass}\\
& \textbf{Momen\rlap{tum}} &&
    \eqmathbox{\frac{\widebar{D}\mathbf{u}'}{Dt} + \frac{1}{\bar{\rho}} \nabla p'
            = \mathbf{0}} & \label{eq:linear_EOM_vector_mom}\\
& \myeqlabel{Energy} &&
    \eqmathbox{c_p\frac{\widebar{D}}{Dt}(\bar{\rho}\,T' + \rho'\widebar{T}) + \nabla \cdot (\boldsymbol{u'}\bar{p} + \bar{\boldsymbol{u}}p')
            = \dot{q}'\bar{\rho} + \bar{\dot{q}}\rho' }& \label{eq:linear_EOM_vector_energy}\\
& \myeqlabel{Entropy} &&
    \eqmathbox{\frac{\widebar{D}s'}{Dt}
            = \frac{\dot{q}'}{\bar{\rho}\,\bar{T}}} & \label{eq:linear_EOM_vector_entropy}\\
& \myeqlabel{Vorticity} &&
    \eqmathbox{\frac{\widebar{D}\boldsymbol{\xi}'}{Dt}
            = \mathbf{0}} & \label{eq:linear_EOM_vector_vorticity}
\end{flalign}
\end{subequations}

\end{document}

Confounding errors when \frontmatter and cleveref interact while using aucklandthesis.cls

The underlying problem has little to do with cleveref in this case. What happens is that calling \frontmatter in aucklandthesis.cls messes up memoir's setup for secnumdepth and, hence, all of your sectioning commands are unnumbered. Therefore, in the MWE at least, \refstepcounter is never called, and your labels miss the information cleveref complains about. If you remove the calls to \cref your document compiles, but with all chapters unnumbered.

The documentclass appears to assume \frontmatter is not to be used at all, since it calls \mainmatter straight from de definition of \maketitle...

It is true that aucklandthesis.cls does not redefine \frontmatter, but it does redefine \mainmatter and, in so doing, leaves out important things of the memoir original. As far as I can tell, you can get things working doing by hand what the class does not do:

\mainmatter
\makeatletter
\@mainmattertrue
\makeatother
\setcounter{secnumdepth}{\value{maxsecnumdepth}}
\pagenumbering{arabic}

But, in this case, it appears this documentclass is not really official to your institution, which means you are not required to use it. In which case you might be better off simply starting from one of the standard classes, memoir itself, or KOMA-Script.

Unfortunately, the original author of the class seems to be long gone from my institution, so I can't ask them about it, and there doesn't seem to be anyone else responsible for maintaining it these days.

Formally, it is a package published on CTAN. Whether its maintainer is still on the institution or not does not change their role wrt to CTAN. Well, that in theory, in practice things might be different... And I did check the documentation and it seems there is no contact information for you to attempt to report this. If you really think sticking to the document class is worth it, you might want to try some contact through CTAN itself. Or, if your institution does advertise this document class as something "official", even if not "required" but just "recommended", you probably should report this to someone at the University.

Best Answer

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[Tex/LaTex] flush text on the left and centre equation of the same line (not working!)

Confounding errors when \frontmatter and cleveref interact while using aucklandthesis.cls

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