Merge pull request #1109 from qiboteam/circuit_output_bugfix

Bugfix to ``MeasurementOutcomes``

src/qibo/result.py

@@ -183,8 +183,13 @@ def __init__(
         self._frequencies = None
         self._repeated_execution_frequencies = None
 
-        for gate in self.measurements:
-            gate.result.reset()
+        if samples is not None:
+            for m in measurements:
+                indices = [self.measurement_gate.qubits.index(q) for q in m.qubits]
+                m.result.register_samples(samples[:, indices])
+        else:
+            for gate in self.measurements:
+                gate.result.reset()
 
     def frequencies(self, binary: bool = True, registers: bool = False):
         """Returns the frequencies of measured samples.

tests/test_measurements_collapse.py

@@ -13,9 +13,10 @@
 def test_measurement_collapse(backend, nqubits, targets):
     initial_state = random_statevector(2**nqubits, backend=backend)
     c = models.Circuit(nqubits)
+    for q in np.random.randint(nqubits, size=np.random.randint(nqubits, size=1)):
+        c.add(gates.H(q))
     r = c.add(gates.M(*targets, collapse=True))
     c.add(gates.M(*targets))
-    # final_state = backend.execute_circuit(c, np.copy(initial_state), nshots=1)[0]
     outcome = backend.execute_circuit(c, np.copy(initial_state), nshots=1)
     samples = r.samples()[0]
     backend.assert_allclose(samples, outcome.samples()[0])

tests/test_models_circuit_noise.py

@@ -186,7 +186,7 @@ def test_circuit_add_sampling(backend):
 
     circ.add(gates.PauliNoiseChannel(0, [("Z", 0.01)]))
     circ += circ_no_noise.invert()
-    circ.add(gates.M(0))
+    measurement = circ.add(gates.M(0))
 
     # Sampling using 10 shots
     np.random.seed(123)
@@ -198,6 +198,7 @@ def test_circuit_add_sampling(backend):
     backend.set_seed(123)
     np.random.seed(123)
     for _ in range(10):
+        measurement.reset()
         result = backend.execute_circuit(circ, nshots=1)
         target_samples.append(result.samples())