The best way to describe this function is with an example:
> x <- c(d=2,a=3,b=1,c=4)
> x
d a b c
2 3 1 4
In the above, we see x is an order vector showing that d
came second, a came third, b came first, and c came
fourth. This is difficult to deal with because one has to search
through the vector to find a particular competitor, or a particular
rank. This would be harder if the vector was longer.
If we wish to answer the question “where did competitor a
come? where did b come?” we would want an order vector
in which the competitors are in alphabetical order. This is
accomplished by ordertrans():
> o <- ordertrans(x)
> o
a b c d
3 1 4 2
(this is equivalent to o <- x[order(names(x))]). Object o
contains the same information as x, but presented differently.
This says that a came third, b came first, c came
fourth, and d came second. In particular, the Plackett-Luce
order statistic is identical:
> ordervec2supp(x) == ordervec2supp(o)
> [1] TRUE
There is a nice example of ordertrans() in
inst/eurovision.Rmd, and file inst/ordertrans.Rmd provides
further discussion and examples.
Function ordertrans() takes a second argument which allows the
user to arrange an order vector into the order specified.
Function ordertrans() also works in the context of hyper3
objects:
x <- c(d=2,a=3,b=1,a=4)
x
d a b a
2 3 1 4
ordertrans(x)
a a b d
3 4 1 2
Object x shows that d came second, a came third and
fourth, and b came first. We can see that ordertrans()
gives the same information in a more intelligible format. This
functionality is useful in the context of hyper3 likelihood
functions.