def prototype_adjacency(self, n_block_features, alpha):
        """Build a new graph.

        Doc for ".create(n_features, alpha)"

        Parameters
        -----------
        n_features : int

        alpha : float (0,1)
            The complexity / sparsity factor.

            Each graph will have a minimum of

                n_blocks * ceil(alpha * n_block_features)

                where

                n_block_features = floor(n_features / self.n_blocks)

            edges and exactly this amount if chain_blocks=False.

        Returns
        -----------
        (n_features, n_features) matrices: covariance, precision, adjacency
        """
        return lattice(
            self.prng,
            n_block_features,
            alpha,
            random_sign=self.random_sign,
            low=self.low,
            high=self.high,
        )
Build a new graph.

        Doc for ".create(n_features, alpha)"

        Parameters
        -----------
        n_features : int

        alpha : float (0,1)
            The complexity / sparsity factor.

            Each graph will have a minimum of

                n_blocks * ceil(alpha * n_block_features)

                where

                n_block_features = floor(n_features / self.n_blocks)

            edges and exactly this amount if chain_blocks=False.

        Returns
        -----------
        (n_features, n_features) matrices: covariance, precision, adjacency