as.function.polynom {PolynomF} | R Documentation |
Since polynom
objects are represented as functions,
as.function.polynom
simply removes the class
attribute.
The function as.function.polylist
produces allows all
polynomials on the list to be evaluated simultaneously at the same
argument value.
## S3 method for class 'polynom': as.function(x, variable = "x", ...) ## S3 method for class 'polylist': as.function(x, ...)
x |
A polynom or polylist object. |
variable |
A character string giving the name to be used for the
formal argument of the resulting function, (for as.polynom
only). |
... |
Not currently used. |
Since polynom
objects are already stored as functions,
as.function.polynom
is rarely needed and may be replaced by
unclass
. An explicit call to as.function.polynom
,
however, will generate a slightly faster version of the function as an
unrooled loop, and does allow the user to specify a different name for
the formal argument to be used.
Since arithmetic on polynomials is provided, both of these
functions may be evaluated at a polynom
object as well as a
numeric argument.
An R
function implementing the evaluation.
Bill Venables
None
x <- polynom() H <- polylist(polynom(1), x) for(j in 2:5) H[[j+1]] <- x*H[[j]] - (j-1)*H[[j-1]] H5 <- as.function(H) H5(-4:4) H5(x+1)