All rank orders of a given size — tda_rank

tda_rank_orders enumerates every rank order of size objects, including all ways of tying them. For three objects there are 13: six strict orders, six with one pair tied, and one with all three tied.

Usage

tda_rank_orders(size = 2, options = list(), dir = tempfile("tda"), ...)

Arguments

size: number of objects to rank, 2 or more.
options: a named list of further TDA options, passed through. m= selects the enumeration variant.
dir: working directory.
...: passed to tda_run.

Value

A data frame with one row per rank order: ties, the number of tie groups, then one column per object (r1, r2, ...) giving its rank. attr(x, "run") carries the run.

Details

Useful as the sample space for a rank-order model – the set of outcomes a distribution over rankings has to sum over – which is otherwise fiddly to generate because of the ties.

Examples

r <- tda_rank_orders(3)
nrow(r)          # 13
#> [1] 13
head(r)
#>   ties r1 r2 r3
#> 1    1  1  1  1
#> 2    2  1  2  2
#> 3    2  2  1  1
#> 4    2  2  1  2
#> 5    2  1  2  1
#> 6    2  2  2  1
table(r$ties)    # 1 all tied, 6 one pair tied, 6 strict
#> 
#> 1 2 3 
#> 1 6 6