Merge pull request #1070 from qiboteam/circuit_output_bugfix

Circuit Execution Output bugfix for the qibojit and qibolab backends

src/qibo/backends/numpy.py

@@ -521,10 +521,12 @@ def execute_circuit_repeated(self, circuit, nshots, initial_state=None):
                 results.append(sample)
                 if not circuit.density_matrix:
                     samples.append("".join([str(s) for s in sample]))
+                for gate in circuit.measurements:
+                    gate.result.reset()
 
         if circuit.density_matrix:  # this implies also it has_collapse
             assert circuit.has_collapse
-            final_state = np.asarray(final_states).mean(0)
+            final_state = np.mean(self.to_numpy(final_states), 0)
             if circuit.measurements:
                 qubits = [q for m in circuit.measurements for q in m.target_qubits]
                 final_result = CircuitResult(

src/qibo/result.py

@@ -67,7 +67,7 @@ def state(self, numpy=False):
             The state in the computational basis.
         """
         if numpy:
-            return np.asarray(self._state)
+            return self.backend.to_numpy(self._state)
         else:
             return self._state
 
@@ -147,15 +147,6 @@ class MeasurementOutcomes:
     def __init__(
         self, measurements, backend, probabilities=None, samples=None, nshots=1000
     ):
-        if probabilities is None and samples is None:
-            raise RuntimeError(
-                "You have to provide either the `probabilities` or the `samples` to build a `MeasurementOutcomes` object."
-            )
-        if probabilities is not None and samples is not None:
-            raise RuntimeError(
-                "Both the `probabilities` and the `samples` were provided to build the `MeasurementOutcomes` object. Don't know which one to use."
-            )
-
         self.backend = backend
         self.measurements = measurements
         self.nshots = nshots
@@ -166,9 +157,6 @@ def __init__(
         self._frequencies = None
         self._repeated_execution_frequencies = None
 
-        for gate in self.measurements:
-            gate.result.reset()
-
     def frequencies(self, binary=True, registers=False):
         """Returns the frequencies of measured samples.
 
@@ -238,10 +226,7 @@ def frequencies(self, binary=True, registers=False):
         return self._frequencies
 
     def has_samples(self):
-        if self._samples is not None:
-            return True
-        else:  # pragma: no cover
-            return False
+        return self.measurements[0].result.has_samples() or self._samples is not None
 
     def samples(self, binary=True, registers=False):
         """Returns raw measurement samples.

tests/test_models_circuit_execution.py

@@ -27,13 +27,13 @@ def create_circuit(theta=0.1234):
 
     # Run eager circuit
     c1 = create_circuit()
-    r1 = backend.execute_circuit(c1)._state
+    r1 = backend.execute_circuit(c1).state()
 
     # Run compiled circuit
     c2 = create_circuit()
     c2.compile(backend)
-    r2 = c2()._state
-    np.testing.assert_allclose(r1, r2)
+    r2 = c2().state()
+    np.testing.assert_allclose(backend.to_numpy(r1), backend.to_numpy(r2))
 
 
 def test_compiling_twice_exception(backend):
@@ -59,14 +59,22 @@ def test_memory_error(backend, accelerators):
 
 
 def test_repeated_execute(backend, accelerators):
-    c = Circuit(4, accelerators, density_matrix=True)
-    thetas = np.random.random(4)
-    c.add((gates.RY(i, t) for i, t in enumerate(thetas)))
-    target_state = backend.execute_circuit(c).state()
-    target_state = target_state
-    c.has_collapse = True
-    final_state = backend.execute_circuit(c, nshots=20)._state
-    backend.assert_allclose(final_state, target_state)
+    if accelerators is not None:
+        with pytest.raises(NotImplementedError):
+            c = Circuit(4, accelerators, density_matrix=True)
+    else:
+        c = Circuit(4, accelerators, density_matrix=True)
+        thetas = np.random.random(4)
+        c.add((gates.RY(i, t) for i, t in enumerate(thetas)))
+        target_state = backend.execute_circuit(c).state()
+        target_state = target_state
+        c.has_collapse = True
+        if accelerators is not None:
+            with pytest.raises(NotImplementedError):
+                final_state = backend.execute_circuit(c, nshots=20)
+        else:
+            final_state = backend.execute_circuit(c, nshots=20).state()
+            backend.assert_allclose(final_state, target_state)
 
 
 def test_final_state_property(backend):
@@ -92,7 +100,7 @@ def test_density_matrix_circuit(backend):
     c.add(gates.H(1))
     c.add(gates.CNOT(0, 1))
     c.add(gates.H(2))
-    final_rho = backend.execute_circuit(c, np.copy(initial_rho))._state
+    final_rho = backend.execute_circuit(c, np.copy(initial_rho)).state()
 
     h = np.array([[1, 1], [1, -1]]) / np.sqrt(2)
     cnot = np.array([[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 0, 1], [0, 0, 1, 0]])
@@ -122,8 +130,8 @@ def test_circuit_as_initial_state(backend, density_matrix):
 
     actual_circuit = c1 + c
 
-    output = backend.execute_circuit(c, c1)._state
-    target = backend.execute_circuit(actual_circuit)._state
+    output = backend.execute_circuit(c, c1).state()
+    target = backend.execute_circuit(actual_circuit).state()
 
     backend.assert_allclose(target, output)
 

tests/test_models_circuit_features.py

@@ -321,4 +321,5 @@ def test_repeated_execute_probs_and_freqs(backend, nqubits):
         else:
             test_frequencies = Counter({"11": 618, "10": 169, "01": 185, "00": 52})
 
-    assert result.frequencies() == test_frequencies
+    for key in dict(test_frequencies).keys():
+        backend.assert_allclose(result.frequencies()[key], test_frequencies[key])

tests/test_result.py

@@ -1,3 +1,5 @@
+from os import remove
+
 import numpy as np
 import pytest
 
@@ -16,26 +18,6 @@ def test_circuit_result_error(backend):
     )
 
 
-def test_measurementoutcomes_errors(backend):
-    c = models.Circuit(1)
-    c.add(gates.M(0))
-    samples = [np.array([1, 0]) for _ in range(5)]
-    with pytest.raises(Exception) as exc_info:
-        MeasurementOutcomes(c.measurements, backend)
-    assert (
-        str(exc_info.value)
-        == "You have to provide either the `probabilities` or the `samples` to build a `MeasurementOutcomes` object."
-    )
-    with pytest.raises(Exception) as exc_info:
-        MeasurementOutcomes(
-            c.measurements, backend, probabilities=np.array([1, 0]), samples=samples
-        )
-    assert (
-        str(exc_info.value)
-        == "Both the `probabilities` and the `samples` were provided to build the `MeasurementOutcomes` object. Don't know which one to use."
-    )
-
-
 def test_measurement_gate_dump_load(backend):
     c = models.Circuit(2)
     c.add(gates.M(1, 0, basis=[gates.Z, gates.X]))
@@ -47,8 +29,6 @@ def test_measurement_gate_dump_load(backend):
 
 @pytest.mark.parametrize("agnostic_load", [False, True])
 def test_measurementoutcomes_dump_load(backend, agnostic_load):
-    from os import remove
-
     c = models.Circuit(2)
     c.add(gates.M(1, 0, basis=[gates.Z, gates.X]))
     # just to trigger repeated execution and test MeasurementOutcomes
@@ -68,8 +48,6 @@ def test_measurementoutcomes_dump_load(backend, agnostic_load):
 
 @pytest.mark.parametrize("agnostic_load", [False, True])
 def test_circuitresult_dump_load(backend, agnostic_load):
-    from os import remove
-
     c = models.Circuit(2, density_matrix=True)
     c.add(gates.M(1, 0, basis=[gates.Z, gates.X]))
     # trigger repeated execution to build the CircuitResult object