collective. This parallelizes work on CPU and speeds up the collective
        performance. Default behavior is unchanged.
    *   Add an option `perturb_singular` to `tf.linalg.tridiagonal_solve` that
        allows solving linear systems with a numerically singular tridiagonal
        matrix, e.g. for use in inverse iteration.
    *   Added `tf.linalg.eigh_tridiagonal` that computes the eigenvalues of a