Function random_permutation

mne/utils/numerics.py:273–307

Emulate the randperm matlab function. It returns a vector containing a random permutation of the integers between 0 and n_samples-1. It returns the same random numbers than randperm matlab function whenever the random_state is the same as the matlab's random seed. This function

(n_samples, random_state=None)

@fill_doc
def random_permutation(n_samples, random_state=None):
    """Emulate the randperm matlab function.

    It returns a vector containing a random permutation of the
    integers between 0 and n_samples-1. It returns the same random numbers
    than randperm matlab function whenever the random_state is the same
    as the matlab's random seed.

    This function is useful for comparing against matlab scripts
    which use the randperm function.

    Note: the randperm(n_samples) matlab function generates a random
    sequence between 1 and n_samples, whereas
    random_permutation(n_samples, random_state) function generates
    a random sequence between 0 and n_samples-1, that is:
    randperm(n_samples) = random_permutation(n_samples, random_state) - 1

    Parameters
    ----------
    n_samples : int
        End point of the sequence to be permuted (excluded, i.e., the end point
        is equal to n_samples-1)
    %(random_state)s

    Returns
    -------
    randperm : ndarray, int
        Randomly permuted sequence between 0 and n-1.
    """
    rng = check_random_state(random_state)
    # This can't just be rng.permutation(n_samples) because it's not identical
    # to what MATLAB produces
    idx = rng.uniform(size=n_samples)
    randperm = np.argsort(idx)
    return randperm


@verbose