permn {combinat}

Generates all permutations of the elements of x

Description

Generates all permutations of the elements of x, in a minimal- change order. If x is a positive integer, returns all permutations of the elements of seq(x). If argument "fun" is not null, applies a function given by the argument to each point. "..." are passed unchanged to the function given by argument fun, if any.

Usage

permn(x, fun=NULL, ...)

Arguments

x

vector

fun

if non.null, applied at each perm

...

args passed to fun

Value

list: each component is either a permutation, or the results of applying fun to a permutation

References

Reingold, E.M., Nievergelt, J., Deo, N. (1977) Combinatorial Algorithms: Theory and Practice. NJ: Prentice-Hall. pg. 170.

See Also

sample, fact, combn, hcube, xsimplex

Examples

    # Convert output to a matrix of dim c(6, 720)
     t(array(unlist(permn(6)), dim = c(6, gamma(7))))
       # A check that every element occurs the same number of times in each
       # position
       apply(t(array(unlist(permn(6)), dim = c(6, gamma(7)))), 2, tabulate,
               nbins = 6)

       # Apply, on the fly, the diff function to every permutation
       t(array(unlist(permn(6, diff)), dim = c(5, gamma(7))))