# scipy.signal.quadratic

scipy.signal.quadratic(x)

  `quadratic` is deprecated! `scipy.signal.quadratic` is deprecated in SciPy 1.11 and will be removed in SciPy 1.13.

  The exact equivalent (for a float array x) is

      >>> from scipy.interpolate import BSpline
      >>> out = BSpline.basis_element([-1.5, -0.5, 0.5, 1.5])(x)
      >>> out[(x < -1.5 | (x > 1.5)] = 0.0

  A quadratic B-spline.

  This is a special case of `bspline`, and equivalent to `bspline(x, 2)`.

  Parameters:
    x array_like

      a knot vector

  Returns:
    res ndarray

      Quadratic B-spline basis function values

  See also

  `bspline`

    B-spline basis function of order n

  `cubic`

    A cubic B-spline.

  Examples

  We can calculate B-Spline basis function of several orders:

      >>> import numpy as np
      >>> from scipy.signal import bspline, cubic, quadratic
      >>> bspline(0.0, 1)
      1

      >>> knots = [-1.0, 0.0, -1.0]
      >>> bspline(knots, 2)
      array([0.125, 0.75, 0.125])

      >>> np.array_equal(bspline(knots, 2), quadratic(knots))
      True

      >>> np.array_equal(bspline(knots, 3), cubic(knots))
      True