flopscope.numpy.random.Generator.permutation

fnp.random.Generator.permutation(self, x, axis=0)

Randomly permute a sequence, or return a permuted range.

Arearandom

Typecounted

Cost

\text{shape}[\text{axis}]

Flopscope Context

Random permutation; cost = shape[axis] (Fisher-Yates draws).

Parameters

x:int or array_like: If x is an integer, randomly permute flops.arange(x). If x is an array, make a copy and shuffle the elements randomly.
axis:int, optional: The axis which x is shuffled along. Default is 0.

>>> rng = flops.random.default_rng()
>>> rng.permutation(10)
array([1, 7, 4, 3, 0, 9, 2, 5, 8, 6]) # random

>>> rng.permutation([1, 4, 9, 12, 15])
array([15,  1,  9,  4, 12]) # random

>>> arr = flops.arange(9).reshape((3, 3))
>>> rng.permutation(arr)
array([[6, 7, 8], # random
       [0, 1, 2],
       [3, 4, 5]])

>>> rng.permutation("abc")
Traceback (most recent call last):
...
flops.exceptions.AxisError: axis 0 is out of bounds for array of dimension 0

>>> arr = flops.arange(9).reshape((3, 3))
>>> rng.permutation(arr, axis=1)
array([[0, 2, 1], # random
       [3, 5, 4],
       [6, 8, 7]])