validate.py 文件源码

def split_cfold(nsamples, k=5, seed=None):
    """
    Function that returns indices for splitting data into random folds.

    Parameters
    ----------
    nsamples: int
        the number of samples in the dataset
    k: int, optional
        the number of folds
    seed: int, optional
        random seed to provide to numpy

    Returns
    -------
    cvinds: list
        list of arrays of length k, each with approximate shape (nsamples /
        k,) of indices. These indices are randomly permuted (without
        replacement) of assignments to each fold.
    cvassigns: ndarray
        array of shape (nsamples,) with each element in [0, k), that can be
        used to assign data to a fold. This corresponds to the indices of
        cvinds.

    """
    np.random.seed(seed)
    pindeces = np.random.permutation(nsamples)
    cvinds = np.array_split(pindeces, k)

    cvassigns = np.zeros(nsamples, dtype=int)
    for n, inds in enumerate(cvinds):
        cvassigns[inds] = n

    return cvinds, cvassigns