mvp (version 1.0-14)

mvp: Multivariate polynomials, mvp objects

Description

Create, test for, an coerce to, mvp objects

Usage

mvp(vars, powers, coeffs)
is_ok_mvp(vars,powers,coeffs)
is.mvp(x)
as.mvp(x)
# S3 method for character
as.mvp(x)
# S3 method for list
as.mvp(x)
# S3 method for mpoly
as.mvp(x)
# S3 method for mvp
as.mvp(x)
# S3 method for numeric
as.mvp(x)

Arguments

vars

List of variables comprising each term of an mvp object

powers

List of powers corresponding to the variables of the vars argument

coeffs

Numeric vector corresponding to the coefficients to each element of the var and powers lists

x

Object to be coerced to or tested for being class mvp

Author

Robin K. S. Hankin

Details

Function mvp() is the formal creation mechanism for mvp objects. However, it is not very user-friendly; it is better to use as.mvp() in day-to-day use.

Function is_ok_mvp() checks for consistency of its arguments.

Examples

mvp(list("x", c("x","y"), "a", c("y","x")), list(1,1:2,3,c(-1,4)), 1:4)

## Note how the terms appear in an arbitrary order, as do
## the symbols within a term.

kahle  <- mvp(
    vars   = split(cbind(letters,letters[c(26,1:25)]),rep(seq_len(26),each=2)),
    powers = rep(list(1:2),26),
    coeffs = 1:26
)
kahle
## again note arbitrary order of terms and symbols within a term

## Standard arithmetic rules apply:

a <- as.mvp("1 + 4*x*y + 7*z")
b <- as.mvp("-7*z + 3*x^34 - 2*z*x")

a+b
a*b^2

(a+b)*(a-b) == a^2-b^2 # should be TRUE