def sfs_scaled(dac, n=None):
    """Compute the site frequency spectrum scaled such that a constant value is
    expected across the spectrum for neutral variation and constant
    population size.

    Parameters
    ----------
    dac : array_like, int, shape (n_variants,)
        Array of derived allele counts.
    n : int, optional
        The total number of chromosomes called.

    Returns
    -------
    sfs_scaled : ndarray, int, shape (n_chromosomes,)
        An array where the value of the kth element is the number of variants
        with k derived alleles, multiplied by k.

    """

    # compute site frequency spectrum
    s = sfs(dac, n=n)

    # apply scaling
    s = scale_sfs(s)

    return s
Compute the site frequency spectrum scaled such that a constant value is
    expected across the spectrum for neutral variation and constant
    population size.

    Parameters
    ----------
    dac : array_like, int, shape (n_variants,)
        Array of derived allele counts.
    n : int, optional
        The total number of chromosomes called.

    Returns
    -------
    sfs_scaled : ndarray, int, shape (n_chromosomes,)
        An array where the value of the kth element is the number of variants
        with k derived alleles, multiplied by k.