The result of rename(x,dim,names) is x
reordered such that dimnames(x)[[dim]] is equal to
the concatenation of those elements of names
that are in dimnames(x)[[dim]] and the remaining elements
of dimnames(x)[[dim]].
The result of rename(x,dim,indices) is x
reordered along dim according to indices.
The result of rename(x,dim,FUN) is x
reordered along dim according to order(apply(x,dim,FUN)).