# scipy.special.perm

scipy.special.perm(N, k, exact=False)

  Permutations of N things taken k at a time, i.e., k-permutations of N.

  It’s also known as “partial permutations”.

  Parameters
    N int, ndarray

      Number of things.

    k int, ndarray

      Number of elements taken.

    exact bool, optional

      If exact is False, then floating point precision is used, otherwise exact long integer is computed.

  Returns
    val int, ndarray

      The number of k-permutations of N.

  Notes

  - Array arguments accepted only for exact=False case.

  - If k > N, N < 0, or k < 0, then a 0 is returned.

  Examples

      >>> from scipy.special import perm
      >>> k = np.array([3, 4])
      >>> n = np.array([10, 10])
      >>> perm(n, k)
      array([  720.,  5040.])
      >>> perm(10, 3, exact=True)
      720

scipy.special.comb scipy.special.lambertw