code: def newton_cotes(rn, equal=0):
      r"""
      Return weights and error coefficient for Newton-Cotes integration.
  
      Suppose we have (N+1) samples of f at the positions
      x_0, x_1, ..., x_N.  Then an N-point Newton-Cotes formula for the
      integral between x_0 and x_N is:
  
      :math:`\int_{x_0}^{x_N} f(x)dx = \Delta x \sum_{i=0}^{N} a_i f(x_i)
      + B_N (\Delta x)^{N+2} f^{N+1} (\xi)`
  
      where :math:`\xi \in [x_0,x_N]`
      and :math:`\Delta x = \frac{x_N-x_0}{N}` is the average samples spacing.
  
      If the samples are equally-spaced and N is even, then the error
      term is :math:`B_N (\Delta x)^{N+3} f^{N+2}(\xi)`.
  
      Parameters
      ----------
      rn : int
          The integer order for equally-spaced data or the relative positions of
          the samples with the first sample at 0 and the last at N, where N+1 is
          the length of `rn`.  N is the order of the Newton-Cotes integration.
      equal : int, optional
          Set to 1 to enforce equally spaced data.
  
      Returns
      -------
      an : ndarray
          1-D array of weights to apply to the function at the provided sample
          positions.
      B : float
          Error coefficient.
  
      Examples
      --------
      Compute the integral of sin(x) in [0, :math:`\pi`]:
  
      >>> from scipy.integrate import newton_cotes
      >>> def f(x):
      ...     return np.sin(x)
      >>> a = 0
      >>> b = np.pi
      >>> exact = 2
      >>> for N in [2, 4, 6, 8, 10]:
      ...     x = np.linspace(a, b, N + 1)
      ...     an, B = newton_cotes(N, 1)
      ...     dx = (b - a) / N
      ...     quad = dx * np.sum(an * f(x))
      ...     error = abs(quad - exact)
      ...     print('{:2d}  {:10.9f}  {:.5e}'.format(N, quad, error))
      ...
       2   2.094395102   9.43951e-02
       4   1.998570732   1.42927e-03
       6   2.000017814   1.78136e-05
       8   1.999999835   1.64725e-07
      10   2.000000001   1.14677e-09
  
      Notes
      -----
      Normally, the Newton-Cotes rules are used on smaller integration
      regions and a composite rule is used to return the total integral.
  
      """
      try:
          N = len(rn) - 1
          if equal:
              rn = np.arange(N + 1)
          elif np.all(np.diff(rn) == 1):
              equal = 1
      except Exception:
          N = rn
          rn = np.arange(N + 1)
          equal = 1
  
      if equal and N in _builtincoeffs:
          na, da, vi, nb, db = _builtincoeffs[N]
          an = na * np.array(vi, dtype=float) / da
          return an, float(nb) / db
  
      if (rn[0] != 0) or (rn[-1] != N):
          raise ValueError(
              "The sample positions must start at 0" " and end at N"
          )
      yi = rn / float(N)
      ti = 2 * yi - 1
      nvec = np.arange(N + 1)
      C = ti ** nvec[:, np.newaxis]
      Cinv = np.linalg.inv(C)
      # improve precision of result
      for i in range(2):
          Cinv = 2 * Cinv - Cinv.dot(C).dot(Cinv)
      vec = 2.0 / (nvec[::2] + 1)
      ai = Cinv[:, ::2].dot(vec) * (N / 2.0)
  
      if (N % 2 == 0) and equal:
          BN = N / (N + 3.0)
          power = N + 2
      else:
          BN = N / (N + 2.0)
          power = N + 1
  
      BN = BN - np.dot(yi**power, ai)
      p1 = power + 1
      fac = power * math.log(N) - gammaln(p1)
      fac = math.exp(fac)
      return ai, BN * fac
  
imports: from __future__ import division, print_function, absolute_import
  import numpy
  import math
  import warnings
  from numpy import trapz
  from scipy.special import roots_legendre
  from scipy.special import gammaln
  from scipy._lib.six import xrange
label_desc: Use image node_id 14 for calling a global function with example usage: newton_cotes(rn, equal) and returns: ai,  unknown, an,  unknown