signal (version 1.8-0)

roots: Roots of a polynomial

Description

Roots of a polynomial

Usage

roots(x, method = c("polyroot", "eigen"))

Value

A complex array with the roots of the polynomial.

Arguments

x

Polynomial coefficients with coefficients given in order from highest to lowest polynomial power. This is the Matlab/Octave convention; it is opposite of the convention used by polyroot.

method

Either “polyroot” (default) which uses polyroot for its computations internally (and is typically more accurate) or “eigen” which uses eigenvalues of the companion matrix for its computation. The latter returns complex values in case of real valued solutions in less cases.

Author

Original Octave version by Kurt Hornik. Conversion to R by Tom Short.

References

Octave Forge https://octave.sourceforge.io/

See Also

polyroot, polyval, poly, conv

Examples

roots(1:3)
polyroot(3:1) # should be the same
poly(roots(1:3))

roots(1:3, method="eigen") # using eigenvalues