Ops.onion {onion} | R Documentation |
Allows arithmetic operators to be used for octonion calculations, such as addition, multiplication, division, integer powers, etc.
## S3 method for class 'onion' Ops(e1, e2) OprodO(oct1, oct2) HprodH(quat1, quat2) R_OprodO(oct1, oct2) R_HprodH(quat1, quat2) AprodA(A, B, ur=getOption("use.R")) AsumA(A, B) Apower(A, B) AequalsA(A, B) AprodS(A, scalar) Ainv(A) Aneg(A) Amassage(A, B) harmonize(A, B)
e1,e2, A, B |
Objects of class “ |
oct1,oct2 |
Octonionic vectors |
quat1,quat2 |
Quaternionic vectors |
scalar |
Scalar vector |
ur |
In function |
The function Ops.onion()
passes unary and binary arithmetic
operators (“+
”, “-
”, “*
”, and
“/
”) to the appropriate specialist function.
The most interesting operator is “*
”, which is passed to
AprodA()
. This function is sensitive to the value of option
use.R
. If this is TRUE
, then arguments are passed, via
Amassage()
, to either R_HprodH()
(for quaternions), or
R_OprodO()
(for octonions). If option use.R
is
anything other than TRUE
(including being unset, which is the
default), the massaged arguments are passed to
HprodH()
or OprodO()
. This is what the user usually
wants: it is much faster than using the R_
functions.
The relative performance of, say, OprodO()
vs
R_OprodO()
, will be system dependent but on my little Linux
system (Fedora; 256MB) OprodO()
runs more than three hundred
times faster than R_OprodO()
. Your mileage may vary; see
examples section for using options()
to set argument ur
.
An object of the appropriate (ie biggest) class as went in,
as per harmonize()
.
The only non obvious ones are Amassage()
, which is used by the
other functions to massage the two arguments into being the same
length, thus emulating recycling.
The other one is harmonize()
that coerces scalars into
quaternions and quaternions into octonions if necessary, returning a
list of two octonions or two quaternions of the same length, for
passing to functions like AprodA()
.
None of these functions are really intended for the end user: use the ops as shown in the examples section.
The “A
” at the beginning of a function name means
Any onion. Thus Ainv()
takes quaternionic or
octonionic arguments, but OprodO()
takes only octonions.
x <- octonion(Re=1 , il=1:3, k=3:1) y <- octonion(Re=1:3, i=1 ,il=3:1) z <- octonion(Re=3:1, j=1 ,jl=1:3) x*9 x+y x*y x/y