polynom {PolynomF} | R Documentation |
The function polynom
is the constructor function for objects of
the eponymous S3 class. as.polynom
is the standad coercion
function to the same class and is.polynom
tests for inheritance
from the class. polylist
objects are lists of polynom
objects, again with the eponymous class.
polynom(a = c(0, 1), ..., eps = 0) as.polynom(a) is.polynom(a) polylist(...) as.polylist(x) is.polylist(x) ## S3 method for class 'polynom': print(x, variable = "x", digits = getOption("digits"), decreasing = FALSE, ...) ## S3 method for class 'polylist': print(x, ...)
a |
Numeric coefficient vector for the constructor, specifying
the coefficients of the powers from 0 to the maximum, without gaps,
in that order, that is, in power series order. For the coercion
and predicate functions this may be a coefficient vector, or an
existing polynom object. |
... |
As yet, unused for polynom but may be used in
future releases. With polylist , objects which are, or may be
coerced to, polynom objects. With print methods,
additional agruments either for the generic or for the
print.polynom method. |
x |
Object which may be coerced to, or tested for, class
polylist . |
eps |
Absolute tolerance below which components are considered zero. |
variable |
Character string giving name to be used for the independent variable. |
digits |
Integer giving the number of significant digits to use in the printed representation of the coefficients. |
decreasing |
Logical value. Should the powers appear in decreasing order? |
polynom
objects are represented as R
functions with the
coefficient vector held in an enclosing environment, or closure. They
may be used as R
functions, or as mathematical objects which behave
under arithmetic and calculus operatons like polynomials.
Note that polynomials with complex coefficients are not (yet) supported. Nevertheless the root-finding methods described elsewhere will usually give complex zeros.
polylist
objects are lists of polynom
objects. Methods
are available for dealing with all polynomials on the list simultaneously.
For polynom
and as.polynom
, an R
function
with class polynom
. For is.polynom
, a logical value
Bill Venables
None
x <- polynom() # polynomial 'x' p <- (x-1)^2 + 10*x^3 + 5*x^4 p # 1 - 2*x + x^2 + 10*x^3 + 5*x^4 plot(polylist(p, deriv(p), integral(p)), xlim = c(-2, 1), ylim = c(-10, 10)) abline(h=0, lty = "dashed", col = "grey") print(p, variable = "z", decreasing = TRUE)