Merge pull request #1047 from qiboteam/chsh

Increase the compatibility between transpiler and chsh

Author: Edoardo-Pedicillo

src/qibocal/protocols/two_qubit_interaction/chsh/circuits.py

@@ -7,7 +7,7 @@
 from .utils import READOUT_BASIS
 
 
-def create_bell_circuit(nqubits, qubits, theta=np.pi / 4, bell_state=0):
+def create_bell_circuit(theta=np.pi / 4, bell_state=0):
     """Creates the circuit to generate the bell states and with a theta-measurement
     bell_state chooses the initial bell state for the test:
     0 -> |00>+|11>
@@ -17,24 +17,24 @@ def create_bell_circuit(nqubits, qubits, theta=np.pi / 4, bell_state=0):
     Native defaults to only using GPI2 and GPI gates.
     """
     p = [0, 0]
-    c = Circuit(nqubits)
-    c.add(gates.H(qubits[0]))
-    c.add(gates.H(qubits[1]))
-    c.add(gates.CZ(qubits[0], qubits[1]))
-    c.add(gates.H(qubits[1]))
+    c = Circuit(2)
+    c.add(gates.H(0))
+    c.add(gates.H(1))
+    c.add(gates.CZ(0, 1))
+    c.add(gates.H(1))
     if bell_state == 1:
-        c.add(gates.Z(qubits[0]))
+        c.add(gates.Z(0))
     elif bell_state == 2:
-        c.add(gates.Z(qubits[0]))
-        c.add(gates.X(qubits[0]))
+        c.add(gates.Z(0))
+        c.add(gates.X(0))
     elif bell_state == 3:
-        c.add(gates.X(qubits[0]))
+        c.add(gates.X(0))
 
-    c.add(gates.RY(qubits[0], theta))
+    c.add(gates.RY(0, theta))
     return c, p
 
 
-def create_bell_circuit_native(nqubits, qubits, theta=np.pi / 4, bell_state=0):
+def create_bell_circuit_native(theta=np.pi / 4, bell_state=0):
     """Creates the circuit to generate the bell states and with a theta-measurement
     bell_state chooses the initial bell state for the test:
     0 -> |00>+|11>
@@ -44,35 +44,33 @@ def create_bell_circuit_native(nqubits, qubits, theta=np.pi / 4, bell_state=0):
     Native defaults to only using GPI2 and GPI gates.
     """
 
-    c = Circuit(nqubits)
+    c = Circuit(2)
     p = [0, 0]
-    c.add(gates.GPI2(qubits[0], np.pi / 2))
-    c.add(gates.GPI2(qubits[1], np.pi / 2))
-    c.add(gates.CZ(qubits[0], qubits[1]))
-    c.add(gates.GPI2(qubits[1], -np.pi / 2))
+    c.add(gates.GPI2(0, np.pi / 2))
+    c.add(gates.GPI2(1, np.pi / 2))
+    c.add(gates.CZ(0, 1))
+    c.add(gates.GPI2(1, -np.pi / 2))
     if bell_state == 0:
         p[0] += np.pi
     elif bell_state == 1:
         p[0] += 0
     elif bell_state == 2:
         p[0] += 0
-        c.add(gates.GPI2(qubits[0], p[0]))
-        c.add(gates.GPI2(qubits[0], p[0]))
+        c.add(gates.GPI2(0, p[0]))
+        c.add(gates.GPI2(0, p[0]))
     elif bell_state == 3:
         p[0] += np.pi
-        c.add(gates.GPI2(qubits[0], p[0]))
-        c.add(gates.GPI2(qubits[0], p[0]))
+        c.add(gates.GPI2(0, p[0]))
+        c.add(gates.GPI2(0, p[0]))
 
-    c.add(gates.GPI2(qubits[0], p[0]))
+    c.add(gates.GPI2(0, p[0]))
     p[0] += theta
-    c.add(gates.GPI2(qubits[0], p[0] + np.pi))
+    c.add(gates.GPI2(0, p[0] + np.pi))
 
     return c, p
 
 
 def create_chsh_circuits(
-    platform,
-    qubits,
     theta=np.pi / 4,
     bell_state=0,
     native=True,
@@ -84,15 +82,14 @@ def create_chsh_circuits(
     """
     create_bell = create_bell_circuit_native if native else create_bell_circuit
     chsh_circuits = {}
-    nqubits = platform.nqubits if platform else max(qubits) + 1
     for basis in readout_basis:
-        c, p = create_bell(nqubits, qubits, theta, bell_state)
+        c, p = create_bell(theta, bell_state)
         for i, base in enumerate(basis):
             if base == "X":
                 if native:
-                    c.add(gates.GPI2(qubits[i], p[i] + np.pi / 2))
+                    c.add(gates.GPI2(i, p[i] + np.pi / 2))
                 else:
-                    c.add(gates.H(qubits[i]))
-        c.add(gates.M(*qubits))
+                    c.add(gates.H(i))
+        c.add(gates.M(0, 1))
         chsh_circuits[basis] = c
     return chsh_circuits

src/qibocal/protocols/two_qubit_interaction/chsh/protocol.py

@@ -76,14 +76,16 @@ class CHSHData(Data):
 
     def save(self, path: Path):
         """Saving data including mitigation matrix."""
-
-        np.savez(
-            path / f"{MITIGATION_MATRIX_FILE}.npz",
-            **{
-                json.dumps((control, target)): self.mitigation_matrix[control, target]
-                for control, target, _, _, _ in self.data
-            },
-        )
+        if self.mitigation_matrix:
+            np.savez(
+                path / f"{MITIGATION_MATRIX_FILE}.npz",
+                **{
+                    json.dumps((control, target)): self.mitigation_matrix[
+                        control, target
+                    ]
+                    for control, target, _, _, _ in self.data
+                },
+            )
         super().save(path=path)
 
     @classmethod
@@ -223,7 +225,6 @@ def _acquisition_circuits(
     backend = GlobalBackend()
     backend.platform = platform
     transpiler = dummy_transpiler(backend)
-    qubit_map = [i for i in range(platform.nqubits)]
     if params.apply_error_mitigation:
         mitigation_data = mitigation_acquisition(
             mitigation_params(nshots=params.nshots), platform, targets
@@ -242,8 +243,6 @@ def _acquisition_circuits(
         for bell_state in params.bell_states:
             for theta in thetas:
                 chsh_circuits = create_chsh_circuits(
-                    platform,
-                    qubits=pair,
                     bell_state=bell_state,
                     theta=theta,
                     native=params.native,
@@ -254,7 +253,7 @@ def _acquisition_circuits(
                         nshots=params.nshots,
                         transpiler=transpiler,
                         backend=backend,
-                        qubit_map=qubit_map,
+                        qubit_map=pair,
                     )
                     frequencies = result.frequencies()
                     data.register_basis(pair, bell_state, basis, frequencies)