  In previous work, we have proposed an entanglement indicator for a general
multiqubit state, which can be "learned" by a quantum system, acting as a
neural network. The indicator can be used for a pure or a mixed state, and it
need not be "close" to any particular state; moreover, as the size of the
system grows, the amount of additional training necessary diminishes. Here, we
show that the indicator is stable to noise and decoherence.
