Unroller duplicates gates when measuring in specific basis

[andrea-pasquale]

When applying a measurement there is the possibility to specify in which basis we want to perform the measurement using the basis argument.

However, when such circuit is transpiled the "rotation gate" appears twice and only once it is correctly transpiled. Here is an example:

from qibo import Circuit, gates
from qibo.transpiler.unroller import NativeGates, Unroller

unroller = Unroller(native_gates=NativeGates.default())

nqubits = 2
circuit = Circuit(nqubits)
circuit.add(gates.M(i, basis=gates.X) for i in range(nqubits))

print(circuit.draw())
# which gives
# q0: ─H─M─
# q1: ─H─M─
transpiled_circuit = unroller(circuit)
print(transpiled_circuit.draw())
# which gives
# q0: ─Z─GPI2─H─M─
# q1: ─Z─GPI2─H─M─

In the transpiled circuit H appears twice, once it is compiled into natives as Z and GPI2 while the second times appears as H which will trigger an error since it is not a native gate. @Edoardo-Pedicillo I believe that this is not related to PRs that you recently open since I am using master.

[Edoardo-Pedicillo]

@Edoardo-Pedicillo I believe that this is not related to PRs that you recently open since I am using master.

I confirm it is not related

[Simone-Bordoni]

I will have a closer look in the next days, i think it should be an easy fix.