### Navigation

- index
- modules |
- next |
- previous |
- NumPy v1.3 Manual (DRAFT) »
- NumPy Reference »
- Routines »
- Polynomials »

# numpy.poly

`numpy.``poly`(seq_of_zeros)

  Return polynomial coefficients given a sequence of roots.

  Calculate the coefficients of a polynomial given the zeros of the polynomial.

  If a square matrix is given, then the coefficients for characteristic equation of the matrix, defined by , are returned.

  Parameters: | seq_of_zeros : ndarray A sequence of polynomial roots or a square matrix.
  Returns: | coefs : ndarray A sequence of polynomial coefficients representing the polynomial :math:`mathrm{coefs}[0] x^{n-1} + mathrm{coefs}[1] x^{n-2} + ... + mathrm{coefs}[2] x + mathrm{coefs}[n]`

  See also

  `numpy.poly1d`
    A one-dimensional polynomial class.
  `numpy.roots`
    Return the roots of the polynomial coefficients in p
  `numpy.polyfit`
    Least squares polynomial fit

  Examples

  Given a sequence of polynomial zeros,

      >>> b = np.roots([1, 3, 1, 5, 6])
      >>> np.poly(b)
      array([ 1.,  3.,  1.,  5.,  6.])

  Given a square matrix,

      >>> P = np.array([[19, 3], [-2, 26]])
      >>> np.poly(P)
      array([   1.,  -45.,  500.])

### Navigation

- index
- modules |
- next |
- previous |
- NumPy v1.3 Manual (DRAFT) »
- NumPy Reference »
- Routines »
- Polynomials »