def to_frequencies(self, fill=np.nan):
        """Compute allele frequencies.

        Parameters
        ----------
        fill : float, optional
            Value to use when number of allele calls is 0.

        Returns
        -------
        af : ndarray, float, shape (n_variants, n_alleles)

        Examples
        --------

        >>> import allel
        >>> g = allel.GenotypeArray([[[0, 0], [0, 1]],
        ...                          [[0, 2], [1, 1]],
        ...                          [[2, 2], [-1, -1]]])
        >>> ac = g.count_alleles()
        >>> ac.to_frequencies()
        array([[0.75, 0.25, 0.  ],
               [0.25, 0.5 , 0.25],
               [0.  , 0.  , 1.  ]])

        """

        an = np.sum(self, axis=1)[:, None]
        with ignore_invalid():
            af = np.where(an > 0, self / an, fill)

        return af
Compute allele frequencies.

        Parameters
        ----------
        fill : float, optional
            Value to use when number of allele calls is 0.

        Returns
        -------
        af : ndarray, float, shape (n_variants, n_alleles)

        Examples
        --------

        >>> import allel
        >>> g = allel.GenotypeArray([[[0, 0], [0, 1]],
        ...                          [[0, 2], [1, 1]],
        ...                          [[2, 2], [-1, -1]]])
        >>> ac = g.count_alleles()
        >>> ac.to_frequencies()
        array([[0.75, 0.25, 0.  ],
               [0.25, 0.5 , 0.25],
               [0.  , 0.  , 1.  ]])