cross-referencingequationsnumbering
I'm writing all my equations with
\begin{equation} ... \end{equation}
so all of them are numbered but only some of them are labeled. I don't want all of them with numbers but only the labeled ones.
Since I have a real big document I don't wanna do this manually using * for all the others. How can I do this automatically?
The mathtools package provides a switch showonlyrefs. You could use that to achieve that only those equations would be numbered which are referred to in the text.
Usage:
\mathtoolsset{showonlyrefs}
or
\mathtoolsset{showonlyrefs=true}
or set it to false this way if desired.
You have misunderstood the purpose of autonum. What determines whether an equation is numbered is not whether it has a \label{}, but whether it is referenced at any point, in other words - whether the document contains a \ref{} referring to that equation or not.
The \cref{} command is also supported, if cleveref is loaded.
For example:
\documentclass{article}
\usepackage{amsmath,cleveref,autonum}
\begin{document}
\begin{multline}\label{eq:a}
z=a+b+c+d+e+f+g\\
+ h+i+j+k+\ell+m+n+o+p+q+r+s+t+u+v+w+x+y.
\end{multline}
\begin{multline}\label{eq:b}
z=a+b+c+d+e+f+g\\
+ h+i+j+k+\ell+m+n+o+p+q+r+s+t+u+v+w+x+y.
\end{multline}
\begin{gather}\label{eq:c}
x=y
\end{gather}
\begin{gather}\label{eq:d}
x=y
\end{gather}
We reference the first \verb|multline| environment, but not the second,
and the second \verb|gather| environment, but not the first.
Hence. only \cref{eq:a} and \cref{eq:d} will be numbered,
even though all equations are labelled.
\end{document}
If you don't want an equation numbered and know you'll never refer to it, you may just as soon use the starred form of the environment. The autonum package is intended specifically to avoid the need to alter the equation itself based on whether it is ever referred to. If it depended on the addition or deletion of a \label{}, the package would lose its point since adding or deleting a star is at least as easy and, arguably, easier.
Best Answer
You have a possibility, with the
mathtoolspackage (that loadsamsmath, so it's useless to load the latter): writein your preamble, and only the
referencedequations will be numbered (use\eqref). It's not exactly what you ask (numberlabelledequations), but you can try to make ‘fake references’ at the very end of your document.