sfsmisc (version 0.9-4)

polyn.eval: Evaluate Polynomials

Description

Evaluate one or several univariate polynomials at several locations, i.e. compute coef[1] + coef[2]*x + ... + coef[p+1]* x^p (in the simplest case where x is scalar and coef a vector).

Usage

polyn.eval(coef, x)

Arguments

coef

numeric vector or matrix. If a vector, x can be an array and the result matches x. If coef is a matrix it specifies several polynomials of the same degree as rows, x must be a vector, coef

x

numeric vector or array. Either x or coef must be a vector.

Value

• numeric vector or array, depending on input dimensionalities, see above.

Details

The stable ``Horner rule'' is used for evaluation in any case.

See Also

For much more sophisticated handling of polynomials, use the polynom package, e.g. predict.polynom.

Examples

polyn.eval(c(1,-2,1), x = 0:3)# (x - 1)^2
polyn.eval(c(0, 24, -50, 35, -10, 1), x = matrix(0:5, 2,3))# 5 zeros!
(cf <- rbind(diag(3), c(1,-2,1)))
polyn.eval(cf, 0:5)