If A is a square N-by-N matrix,
)is the row vector of the coefficients of
det (z * eye (N) - A), the characteristic polynomial of A. For example, the following code finds the eigenvalues of A which are the roots of
).roots (poly (eye (3))) ⇒ 1.00001 + 0.00001i 1.00001 - 0.00001i 0.99999 + 0.00000i
In fact, all three eigenvalues are exactly 1 which emphasizes that for numerical performance the
eigfunction should be used to compute eigenvalues.
If x is a vector,
)is a vector of the coefficients of the polynomial whose roots are the elements of x. That is, if c is a polynomial, then the elements of d
= roots (poly (c
))are contained in c. The vectors c and d are not identical, however, due to sorting and numerical errors.
Write formatted polynomialc(x) = c(1) * x^n + ... + c(n) x + c(n+1)
and return it as a string or write it to the screen (if nargout is zero). x defaults to the string
See also: polyreduce.
Reduce a polynomial coefficient vector to a minimum number of terms by stripping off any leading zeros.
See also: polyout.