By rearranging (copy-and-pasting) math environments the automatically RefTeX generated label numbers
\begin{align}
\label{eq:5}
...
\end{align}
texttexttext...
\begin{align}
\label{eq:3}
...
\end{align}
become shuffled which makes the referencing to individual equations difficult.
How it is possible to rename the label names so that an increasing order is recovered?
I like how you asked "how is it possible to..." instead of "is it possible to...". Because of course it is possible, reftex being awesome and OCD-friendly. :)
reftex-renumber-simple-labelsis an interactive autoloaded Lisp function.Renumber all simple labels in the document to make them sequentially.
So... M-x reftex-renumber-simple-labels RET y and you are done. It should even work across files. Note that you will get an error if the labels are already ordered, though.
\label / \refsystem is that you can use labels that are meaningful to you, rather than being a random number, and then LaTeX sorts out the numbering for you. I would recommend using e.g. a label such aseq:Einsteinfor the Einstein equation, instead of numbered labels. – Andrew Swann Jan 8 '13 at 14:32C-c C-)), which, together with automatic numbering, makes the key of the label more or less useless. – T. Verron Jan 8 '13 at 14:43reftexall the time, but find itvery helpful to have keys that have meaningful names when working with my source. – Andrew Swann Jan 8 '13 at 20:53