as.pairwise
Convert a results matrix to a board
Given a square matrix giving the results of pairwise comparisons, return a board object whose rows show the results of the comparisons.
- Keywords
- math
Usage
as.pairwise(x)
Arguments
- x
- A square matrix
Details
With x
an $n$-by-$n$ square matrix, the rows and
columns each correspond to one of $n$ NA
s because a
competitor can't play himself).
Function as.pairwise()
turns this into a
$n(n-1)/2$-by-$n$ matrix whose rows each correspond to a
pairwise comparison. Any row has exactly two non-NA
entries,
in columns $i$ and $j$, that correspond to elements
$(i,j)$ and $(j,i)$ of x
. Thus the entry in column
$i$ is the number of times competitor $i$ beats competitor
$j$; and the entry in column $j$ is the number of times
competitor $j$ beats competitor $i$.
See Also
Examples
a <- matrix(rpois(25,4),5,5)
rownames(a) <- letters[1:5]
colnames(a) <- letters[1:5]
as.pairwise(a)