Update version of the Floquet calibration (#4557)

* Support features of the Floquet calibration version 2

* Remove debug print and update floquet calibration version

* Add tests for version parameter

* Fix json serialization tests

* Improve tests

Author: mrwojtek

cirq-google/cirq_google/calibration/phased_fsim.py

@@ -570,6 +570,8 @@ class FloquetPhasedFSimCalibrationOptions(PhasedFSimCalibrationOptions):
     characterize_gamma: bool
     characterize_phi: bool
     readout_error_tolerance: Optional[float] = None
+    version: int = 2
+    measure_qubits: Optional[Tuple[cirq.Qid, ...]] = None
 
     def zeta_chi_gamma_correction_override(self) -> PhasedFSimCharacterization:
         """Gives a PhasedFSimCharacterization that can be used to override characterization after
@@ -664,6 +666,8 @@ def from_moment(cls, moment: cirq.Moment, options: FloquetPhasedFSimCalibrationO
 
     def to_calibration_layer(self) -> CalibrationLayer:
         circuit = cirq.Circuit(self.gate.on(*pair) for pair in self.pairs)
+        if self.options.measure_qubits is not None:
+            circuit += cirq.Moment(cirq.measure(*self.options.measure_qubits))
         args: Dict[str, Any] = {
             'est_theta': self.options.characterize_theta,
             'est_zeta': self.options.characterize_zeta,
@@ -672,6 +676,7 @@ def to_calibration_layer(self) -> CalibrationLayer:
             'est_phi': self.options.characterize_phi,
             # Experimental option that should always be set to True.
             'readout_corrections': True,
+            'version': self.options.version,
         }
         if self.options.readout_error_tolerance is not None:
             # Maximum error of the diagonal elements of the two-qubit readout confusion matrix.

cirq-google/cirq_google/calibration/phased_fsim_test.py

@@ -118,6 +118,38 @@ def test_floquet_to_calibration_layer():
             'est_gamma': False,
             'est_phi': True,
             'readout_corrections': True,
+            'version': 2,
+        },
+    )
+
+
+def test_floquet_to_calibration_layer_with_version_override():
+    q_00, q_01, q_02, q_03 = [cirq.GridQubit(0, index) for index in range(4)]
+    gate = cirq.FSimGate(theta=np.pi / 4, phi=0.0)
+    request = FloquetPhasedFSimCalibrationRequest(
+        gate=gate,
+        pairs=((q_00, q_01), (q_02, q_03)),
+        options=FloquetPhasedFSimCalibrationOptions(
+            characterize_theta=True,
+            characterize_zeta=True,
+            characterize_chi=False,
+            characterize_gamma=False,
+            characterize_phi=True,
+            version=3,
+        ),
+    )
+
+    assert request.to_calibration_layer() == cirq_google.CalibrationLayer(
+        calibration_type='floquet_phased_fsim_characterization',
+        program=cirq.Circuit([gate.on(q_00, q_01), gate.on(q_02, q_03)]),
+        args={
+            'est_theta': True,
+            'est_zeta': True,
+            'est_chi': False,
+            'est_gamma': False,
+            'est_phi': True,
+            'readout_corrections': True,
+            'version': 3,
         },
     )
 
@@ -150,6 +182,41 @@ def test_floquet_to_calibration_layer_readout_thresholds():
             'readout_corrections': True,
             'readout_error_tolerance': 0.4,
             'correlated_readout_error_tolerance': 7 / 6 * 0.4 - 1 / 6,
+            'version': 2,
+        },
+    )
+
+
+def test_floquet_to_calibration_layer_with_measure_qubits():
+    qubits = tuple(cirq.GridQubit(0, index) for index in range(5))
+    q_00, q_01, q_02, q_03, _ = qubits
+    gate = cirq.FSimGate(theta=np.pi / 4, phi=0.0)
+    request = FloquetPhasedFSimCalibrationRequest(
+        gate=gate,
+        pairs=((q_00, q_01), (q_02, q_03)),
+        options=FloquetPhasedFSimCalibrationOptions(
+            characterize_theta=True,
+            characterize_zeta=True,
+            characterize_chi=False,
+            characterize_gamma=False,
+            characterize_phi=True,
+            measure_qubits=qubits,
+        ),
+    )
+
+    assert request.to_calibration_layer() == cirq_google.CalibrationLayer(
+        calibration_type='floquet_phased_fsim_characterization',
+        program=cirq.Circuit(
+            [gate.on(q_00, q_01), gate.on(q_02, q_03), cirq.measure(*qubits)],
+        ),
+        args={
+            'est_theta': True,
+            'est_zeta': True,
+            'est_chi': False,
+            'est_gamma': False,
+            'est_phi': True,
+            'readout_corrections': True,
+            'version': 2,
         },
     )
 

cirq-google/cirq_google/json_test_data/FloquetPhasedFSimCalibrationOptions.json

@@ -5,5 +5,7 @@
   "characterize_chi": false,
   "characterize_gamma": true,
   "characterize_phi": false,
-  "readout_error_tolerance": 0.4
+  "readout_error_tolerance": 0.4,
+  "version": 2,
+  "measure_qubits": null
 }

cirq-google/cirq_google/json_test_data/FloquetPhasedFSimCalibrationOptions.repr

@@ -1 +1 @@
-cirq_google.FloquetPhasedFSimCalibrationOptions(characterize_theta=True, characterize_zeta=True, characterize_chi=False, characterize_gamma=True, characterize_phi=False, readout_error_tolerance=0.4)
+cirq_google.FloquetPhasedFSimCalibrationOptions(characterize_theta=True, characterize_zeta=True, characterize_chi=False, characterize_gamma=True, characterize_phi=False, readout_error_tolerance=0.4, version=2)

cirq-google/cirq_google/json_test_data/FloquetPhasedFSimCalibrationRequest.json

@@ -38,6 +38,8 @@
     "characterize_chi": false,
     "characterize_gamma": false,
     "characterize_phi": true,
-    "readout_error_tolerance": 0.4
+    "readout_error_tolerance": 0.4,
+    "version": 2,
+    "measure_qubits": null
   }
 }

cirq-google/cirq_google/json_test_data/FloquetPhasedFSimCalibrationRequest.repr

@@ -8,5 +8,6 @@ cirq_google.FloquetPhasedFSimCalibrationRequest(
                 characterize_gamma=False,
                 characterize_phi=True,
                 readout_error_tolerance=0.4,
+                version=2
             ),
         )

cirq-google/cirq_google/json_test_data/PhasedFSimCalibrationResult.json

@@ -54,7 +54,9 @@
     "characterize_chi": false,
     "characterize_gamma": false,
     "characterize_phi": true,
-    "readout_error_tolerance": 0.4
+    "readout_error_tolerance": 0.4,
+    "version": 2,
+    "measure_qubits": null
   },
   "project_id": "project_id",
   "program_id": "program_id",

cirq-google/cirq_google/json_test_data/PhasedFSimCalibrationResult.repr

@@ -15,6 +15,7 @@ cirq_google.PhasedFSimCalibrationResult(
                 characterize_gamma=False,
                 characterize_phi=True,
                 readout_error_tolerance=0.4,
+                version=2
             ),
             project_id='project_id',
             program_id='program_id',