I found a possible error in the implementation of the xy_mixer.
If the number of qubits is odd the corrent implementation of the mixer does not close the ring as it leaves the qubits 0 and 1 not connected.
In case the number of qubits is even, the mixer closes the ring correctly.
I think it is correct to always close the mixer in both cases.
I found a possible error in the implementation of the xy_mixer. If the number of qubits is odd the corrent implementation of the mixer does not close the ring as it leaves the qubits 0 and 1 not connected. In case the number of qubits is even, the mixer closes the ring correctly. I think it is correct to always close the mixer in both cases.