permutations (version 1.1-9-1)

tidy: Utilities to neaten permutation objects

Description

Various utilities to neaten word objects by removing fixed elements

Usage

tidy(x)
trim(x)

Value

Returns an object of class word

Arguments

x

Object of class word, or in the case of tidy(), coerced to class word

Author

Robin K. S. Hankin

Details

Function trim() takes a word and, starting from the right, strips off columns corresponding to fixed elements until it finds a non-fixed element. This makes no sense for cycle objects; if x is of class cycle, an error is returned.

Function tidy() is more aggressive. This firstly removes all fixed elements, then renames the non-fixed ones to match the new column numbers. The map is an isomorphism (sic) with respect to composition.

See Also

fixed,size,nicify_cyclist

Examples

as.cycle(5:3) + as.cycle(7:9)
tidy(as.cycle(5:3) + as.cycle(7:9))

as.cycle(tidy(c(as.cycle(1:2), as.cycle(6:7))))


nicify_cyclist(list(c(4,6), c(7), c(2,5,1), c(8,3)))

data(megaminx)
tidy(megaminx)  # has 120 columns, not 129
stopifnot(all(unique(sort(unlist(as.cycle(tidy(megaminx)), recursive=TRUE))) == 1:120))

jj <- megaminx*megaminx[1]
stopifnot(identical(shape(jj), shape(tidy(jj))))  #tidy() does not change shape