feat: prep the variance computation on cirq

Author: Henri-ColibrITD

mpqp/execution/providers/google.py

@@ -16,6 +16,7 @@
 from mpqp.execution.devices import GOOGLEDevice
 from mpqp.execution.job import Job, JobType
 from mpqp.execution.result import Result, Sample, StateVector
+from mpqp.tools.generics import flatten
 
 
 @typechecked
@@ -114,7 +115,8 @@ def run_local(job: Job) -> Result:
         ValueError: If the job device is not GOOGLEDevice.
     """
     from cirq.circuits.circuit import Circuit as CirqCircuit
-    from cirq.ops.linear_combinations import PauliSum as Cirq_PauliSum
+    from cirq.ops.linear_combinations import PauliSum as CirqPauliSum
+    from cirq.ops.pauli_string import PauliString as CirqPauliString
     from cirq.sim.sparse_simulator import Simulator
     from cirq.work.observable_measurement import (
         RepetitionsStoppingCriteria,
@@ -150,7 +152,9 @@ def run_local(job: Job) -> Result:
         cirq_obs = job.measure.observable.to_other_language(
             language=Language.CIRQ, circuit=cirq_circuit
         )
-        assert type(cirq_obs) == Cirq_PauliSum
+        assert isinstance(cirq_obs, CirqPauliSum) or isinstance(
+            cirq_obs, CirqPauliString
+        )
 
         if job.measure.shots == 0:
             result_sim = simulator.simulate_expectation_values(
@@ -159,11 +163,11 @@ def run_local(job: Job) -> Result:
         else:
             result_sim = measure_observables(
                 cirq_circuit,
-                observables=cirq_obs,  # type: ignore[reportArgumentType]
+                observables=flatten(cirq_obs),
                 sampler=simulator,
                 stopping_criteria=RepetitionsStoppingCriteria(job.measure.shots),
             )
-
+        print(result_sim)
         return extract_result_OBSERVABLE(result_sim, job)
     else:
         raise ValueError(f"Job type {job.job_type} not handled")
@@ -313,7 +317,7 @@ def extract_result_OBSERVABLE(
         raise NotImplementedError("job.measure is None")
     for result in results:
         if isinstance(result, float):
-            mean += abs(result)
+            mean += result
         if isinstance(result, ObservableMeasuredResult):
             mean += result.mean
             # TODO variance not supported variance += result1.variance