\cdbalgorithm{weyl\_index\_order}{}

Sorts the indices on a \deprecated 
Riemann or Weyl tensor by first applying anti-symmetry in each pair,
and subsequently sorting the pairs by using symmetry under pair
exchange. This alphabetical sorting can be prohibited by giving a
list of indices which is preferred to be in the first pair.
\begin{screen}{1,2,4}
R_{s2 s1 s3 r1};
@weyl_index_order(%){s1};
R_{s1 s2 r1 s3}
@weyl_index_order(%);
R_{r1 s3 s1 s2}
\end{screen}
~
