polyroot

0th

Percentile

Find Zeros of a Real or Complex Polynomial

Find zeros of a real or complex polynomial.

Keywords
math
Usage
polyroot(z)
Arguments
z

the vector of polynomial coefficients in increasing order.

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.

Value

A complex vector of length \(n - 1\), where \(n\) is the position of the largest non-zero element of z.

References

Jenkins, M. A. and Traub, J. F. (1972). Algorithm 419: zeros of a complex polynomial. Communications of the ACM, 15(2), 97--99. 10.1145/361254.361262.

See Also

uniroot for numerical root finding of arbitrary functions; complex and the zero example in the demos directory.

Aliases
  • polyroot
Examples
library(base) # NOT RUN { polyroot(c(1, 2, 1)) round(polyroot(choose(8, 0:8)), 11) # guess what! for (n1 in 1:4) print(polyroot(1:n1), digits = 4) polyroot(c(1, 2, 1, 0, 0)) # same as the first # }
Documentation reproduced from package base, version 3.5.1, License: Part of R 3.5.1

Community examples

Looks like there are no examples yet.