print: Print clifford objects

In clifford: Arbitrary Dimensional Clifford Algebras

Print clifford objects

Description

Print methods for Clifford algebra

Usage

## S3 method for class 'clifford'
print(x,...)
## S3 method for class 'clifford'
as.character(x,...)
catterm(a)

Arguments

x	Object of class clifford in the print method
...	Further arguments, currently ignored
a	Integer vector representing a term

Note

The print method does not change the internal representation of a clifford object, which is a two-element list, the first of which is a list of integer vectors representing terms, and the second is a numeric vector of coefficients. The print method has special dispensation for the zero clifford object.

The print method is sensitive to the value of options separate and basissep. If option separate is FALSE (the default), the method prints the basis blades in a compact form, as in “e_134”. The indices of the basis vectors are separated with the value of option basissep which is usually NULL; but if n>9, then setting option basissep to a comma (“,”) might look good as it will print e_10,11,12 instead of e_101112:

options("basissep" = ",")

If option separate is TRUE, the method prints the basis vectors separately, as in e10 e11 e12:

options("separate" = TRUE)

Function catterm() is a low-level helper function, used in the print method, coercion to character, and also in function getcoeffs() to set the names of its output. It takes an integer vector like c(1,5,6) and returns a representation of the corresponding basis blade, in this case “e_156”. Function catterm() is where options basissep and separate are processed. Special dispensation is needed for length-zero vectors, for which the empty string is returned. This is needed to ensure that the constant term (which has a basis blade of numeric(0)) is treated appropriately. See also list_modifier() which deals with this issue.

Experimental bespoke print method print_clifford_quaternion() and print_clifford_pauli() is included. This are executed if option clifford_print_special is quaternion; if NULL, then print_clifford_default() is used. It is straightforward to add further bespoke print methods if needed (modify print.clifford()).

Author(s)

Robin K. S. Hankin

See Also

clifford

Examples

a <- rclifff(9)
a   # default print method incomprehensible

options("separate" = TRUE)
a    # marginally better


options("separate" = FALSE)
options(basissep=",")
a    #  clearer; YMMV

options(basissep = NULL, maxdim=NULL)  # restore default

options("maxdim" = 3)
signature(3)
a <- clifford(list(0,c(1,2),c(1,3),c(2,3)),6:9)
a

options("clifford_print_special" = "quaternion")
a

options("maxdim" = NULL)
options("clifford_print_special" = NULL)
signature(Inf)

clifford documentation built on June 8, 2025, 10:56 a.m.