show: Print method for onions

In RobinHankin/onion: Octonions and Quaternions

Print method for onions

Description

Show methods for onions

Usage

## S4 method for signature 'onion'
show(object)
onion_show(x,
     comp = getOption("show_onions_compactly"),
     h    = getOption("show_onions_horizontally")
)
comp_names(x)

Arguments

x, object	Onions
comp	Boolean, with TRUE meaning to print onions compactly and any other value to print in matrix form
h	Boolean, with TRUE meaning to print by columns and any other value meaning to print horizontally

Details

TLDR: the print method uses onion_show(). This converts its argument to an appropriate matrix by adjusting the column names if necessary. This matrix is printed to the console using the standard print method for matrices, and hence is sensitive to getOption("digits").

Default behaviour is to print by rows. To print by columns, set option show_onions_horizontally to TRUE:

options("show_onions_horizontally" = TRUE)

Any non-TRUE value (including NULL and its being unset) will restore the default.

Similarly, to show onions compactly, set option show_onions_compactly to TRUE:

options("show_onions_compactly" = TRUE)

This option works best for simple onions with integer entries (or at least values with few decimal places), and especially if there are many zero entries.

Function onion_show() is a helper function, not really intended for the end-user.

The “names” of the components of an onion (viz Re, i, j, k for quaternions and Re, i, j, k, l,il,jl,kl for octonions) are given by function comp_names() which takes either a character string or an onion.

Note

The print method for onionmat objects is also sensitive to these options.

Author(s)

Robin K. S. Hankin

Examples

x <- roct(15)
x  #default

options("show_onions_horizontally" = TRUE)
roct(4) 

options("show_onions_horizontally" = FALSE)  # restore default

options("show_onions_compactly" = TRUE)
x <- as.quaternion(matrix(sample(c(0,0,0,-1,1),80,replace=TRUE),4,20))
options("show_onions_compactly" = FALSE) # restore default

RobinHankin/onion documentation built on Feb. 17, 2025, 7:31 a.m.