gips_perm {gips}

Permutation object

Description

Create permutation objects to be passed to other functions of the gips package.

Usage

gips_perm(x, size)

new_gips_perm(rearranged_cycles, size)

validate_gips_perm(g)

Arguments

x

A single object that can be interpreted by the permutations::permutation() function. For example, the character of a form "(1,2)(4,5)". See examples. It can also be of a gips class but it will be interpreted as the underlying gips_perm.

size

An integer. Size of a permutation (AKA cardinality of a set, on which permutation is defined. See examples).

rearranged_cycles

A list of rearranged integer vectors. Each vector corresponds to a single cycle of a permutation.

g

Object to be checked whether it is a proper object of a gips_perm class.

Value

gips_perm() returns an object of a gips_perm class after the safety checks.

new_gips_perm() returns an object of a gips_perm class without the safety checks.

validate_gips_perm() returns its argument unchanged. If the argument is not a proper element of a gips_perm class, it produces an error.

Functions

• new_gips_perm(): Constructor. Only intended for low-level use.

• validate_gips_perm(): Validator. Only intended for low-level use.

Methods for a gips class

• as.character.gips_perm()

• print.gips_perm()

See Also

• project_matrix() - gips_perm is the perm parameter of project_matrix().

• permutations::permutation() - The constructor for the x parameter.

• gips() - The constructor for the gips class uses the gips_perm object as the base object.

Examples

# All 7 following lines give the same output:
gperm <- gips_perm("(12)(45)", 5)
gperm <- gips_perm("(1,2)(4,5)", 5)
gperm <- gips_perm(as.matrix(c(2, 1, 3, 5, 4)), 5)
gperm <- gips_perm(t(as.matrix(c(2, 1, 3, 5, 4))), 5) # both way for a matrix works
gperm <- gips_perm(list(list(c(2, 1), c(4, 5))), 5)
gperm <- gips_perm(permutations::as.word(c(2, 1, 3, 5, 4)), 5)
gperm <- gips_perm(permutations::as.cycle("(1,2)(4,5)"), 5)
gperm

# note the necessity of the `size` parameter:
gperm <- gips_perm("(12)(45)", 5)
gperm <- gips_perm("(12)(45)", 7) # this one is a different permutation

try(gperm <- gips_perm("(12)(45)", 4))
# Error, `size` was set to 4, while the permutation has the element 5.