def expand_tpm(tpm):
    """Broadcast a state-by-node TPM so that singleton dimensions are expanded
    over the full network.
    """
    unconstrained = np.ones([2] * (tpm.ndim - 1) + [tpm.shape[-1]])
    return tpm * unconstrained
Broadcast a state-by-node TPM so that singleton dimensions are expanded
    over the full network.