polyroot: Find Zeros of a Real or Complex Polynomial
Description
Find zeros of a real or complex polynomial.
Usage
polyroot(z)
Arguments
z
the vector of polynomial coefficients in increasing order.
Value
A complex vector of length n - 1, where n is the position
of the largest non-zero element of z.
Source
C translation by Ross Ihaka of Fortran code in the reference, with
modifications by the R Core Team.
Details
A polynomial of degree $n - 1$,
$$
p(x) = z_1 + z_2 x + \cdots + z_n x^{n-1}$$
is given by its coefficient vector z[1:n].
polyroot returns the $n-1$ complex zeros of $p(x)$
using the Jenkins-Traub algorithm.
If the coefficient vector z has zeroes for the highest powers,
these are discarded.
There is no maximum degree, but numerical stability
may be an issue for all but low-degree polynomials.