This produces a crosstable between two integer vectors (partitions) of
the same length with a given maximum vector entry k so that the
size of the table is k*k with zeroes for missing entries
between 1 and k (the command table does pretty
much the same thing but will leave out missing entries).
Usage
xtable(c1,c2,k)
Value
A matrix of dimensions c(k,k). Entry [i,j] gives the
number of places in which c1==i & c2==j.
Arguments
c1
vector of integers.
c2
vector of integers of same length as c1.
k
integer. Must be larger or equal to maximum entry in
c1 and c2.