size {permutations} | R Documentation |
Gets or sets the size of a permutation
Description
The ‘size’ of a permutation is the cardinality of the set for which it is a bijection.
Usage
size(x)
addcols(M,n)
## S3 method for class 'word'
size(x)
## S3 method for class 'cycle'
size(x)
## S3 replacement method for class 'word'
size(x) <- value
## S3 replacement method for class 'cycle'
size(x) <- value
Arguments
x |
A permutation object |
M |
A matrix that may be coerced to a word |
n , value |
the size to set to, an integer |
Details
For a word
object, the size is equal to the number of columns.
For a cycle
object, it is equal to the largest element of any
cycle.
Function addcols()
is a low-level function that operates on, and
returns, a matrix. It just adds columns to the right of M
, with
values equal to their column numbers, thus corresponding to fixed
elements. The resulting matrix has n
columns. This function
cannot remove columns, so if n<ncol(M)
an error is returned.
Setting functions cannot decrease the size of a permutation; use
trim()
for this.
It is meaningless to change the size of a cycle
object. Trying
to do so will result in an error. But you can coerce cycle objects to
word
form, and change the size of that.
Author(s)
Robin K. S. Hankin
See Also
Examples
size(as.cycle(c("(17)","(123)(45)"))) # should be 7
x <- as.word(as.cycle("123"))
print_word(x)
size(x) <- 9
print_word(x)
size(as.cycle(1:5) + as.cycle(100:101))
size(id)