Add tests

app/CKT_cutter.py

@@ -50,9 +50,11 @@ def cut_circuit(cutting_request: CutCircuitsRequest):
     return CKTCutCircuitsResponse(format=cutting_request.circuit_format, **res)
 
 
-def automatic_cut(circuit, qubits_per_subcircuit, max_cuts=None):
+def automatic_cut(
+    circuit, qubits_per_subcircuit, max_cuts=None, optimization_seed=None
+):
     # Specify settings for the cut-finding optimizer
-    optimization_settings = OptimizationParameters(seed=111)
+    optimization_settings = OptimizationParameters(seed=optimization_seed)
 
     # Specify the size of the QPUs available
     device_constraints = DeviceConstraints(qubits_per_subcircuit=qubits_per_subcircuit)

app/utils.py

@@ -123,3 +123,7 @@ def remove_bits(number, bit_positions):
         number = left_part | right_part
 
     return number
+
+
+def replace_str_index(text, index=0, replacement=""):
+    return f"{text[:index]}{replacement}{text[index+1:]}"

test/test_CKT_cutter.py

@@ -5,12 +5,26 @@
 from collections import defaultdict
 
 import numpy as np
+from circuit_knitting.cutting import (
+    DeviceConstraints,
+    OptimizationParameters,
+    find_cuts,
+    cut_wires,
+    expand_observables,
+    partition_problem,
+    generate_cutting_experiments,
+    reconstruct_expectation_values,
+)
+from qiskit import QuantumCircuit
 from qiskit.circuit.random import random_circuit
-from qiskit_aer.primitives import Sampler
+from qiskit.quantum_info import SparsePauliOp
+from qiskit_aer import AerSimulator
+from qiskit_aer.primitives import Sampler, EstimatorV2
+from qiskit_ibm_runtime.qiskit.primitives import BackendSamplerV2
 
 from app import create_app
 from app.CKT_cutter import automatic_cut, reconstruct_distribution
-from app.utils import counts_to_array
+from app.utils import counts_to_array, replace_str_index
 
 
 class CutFindingTestCase(unittest.TestCase):
@@ -109,6 +123,128 @@ def test_reconstruction(self):
         reconstructed_dist = counts_to_array(reconstructed_counts, circuit.num_qubits)
 
         self.assertTrue(
-            np.allclose(exact_distribution, reconstructed_dist, atol=0.025),
+            np.allclose(exact_distribution, reconstructed_dist, atol=0.1),
             msg=f"\nExact distribution: {exact_distribution}\nReconstruced distribution: {reconstructed_dist}\nDiff: {np.abs(exact_distribution- reconstructed_dist)}",
         )
+
+    def test_reconstruction_2(self):
+
+        circuit = QuantumCircuit(4)
+        circuit.x(0)
+        circuit.cx(0, 1)
+        circuit.cx(1, 2)
+        circuit.cx(2, 3)
+        circuit.cx(3, 2)
+        circuit.cx(2, 1)
+        circuit.cx(1, 0)
+
+        exact_expval_list, actual_expval_list = get_expals(circuit, 2 ** 12)
+
+        self.assertTrue(
+            np.allclose(exact_expval_list, actual_expval_list, atol=0.1),
+            msg=f"\nExact expectations: {exact_expval_list}\nReconstruced expectations: {actual_expval_list}",
+        )
+
+    def test_reconstruction_3(self):
+
+        circuit = QuantumCircuit(4)
+        circuit.h(0)
+        circuit.cx(0, 1)
+        circuit.cx(1, 2)
+        circuit.cx(2, 3)
+        circuit.cx(3, 2)
+        circuit.cx(2, 1)
+        circuit.cx(1, 0)
+
+        exact_expval_list, actual_expval_list = get_expals(circuit, 2 ** 12)
+
+        self.assertTrue(
+            np.allclose(exact_expval_list, actual_expval_list, atol=0.1),
+            msg=f"\nExact expectations: {exact_expval_list}\nReconstruced expectations: {actual_expval_list}",
+        )
+
+    def test_reconstruction_3(self):
+
+        circuit = QuantumCircuit(4)
+        circuit.h(0)
+        circuit.cx(0, 1)
+        circuit.cx(1, 2)
+        circuit.cx(2, 3)
+        circuit.cx(3, 2)
+        circuit.cx(2, 1)
+        circuit.cx(1, 0)
+
+        exact_expval_list, actual_expval_list = get_expals(circuit, 2 ** 12)
+
+        self.assertTrue(
+            np.allclose(exact_expval_list, actual_expval_list, atol=0.1),
+            msg=f"\nExact expectations: {exact_expval_list}\nReconstruced expectations: {actual_expval_list}",
+        )
+
+    def test_reconstruction_4(self):
+
+        circuit = QuantumCircuit(5)
+        circuit.x(0)
+        circuit.cx(0, 1)
+        circuit.cx(1, 2)
+        circuit.cx(1, 0)
+        circuit.cx(2, 0)
+        circuit.cx(2, 3)
+        circuit.cx(3, 4)
+        circuit.cx(2, 4)
+
+        exact_expval_list, actual_expval_list = get_expals(circuit, 2 ** 12)
+
+        self.assertTrue(
+            np.allclose(exact_expval_list, actual_expval_list, atol=0.1),
+            msg=f"\nExact expectations: {exact_expval_list}\nReconstruced expectations: {actual_expval_list}",
+        )
+
+
+def get_expals(circuit, shots):
+    n_qubits = circuit.num_qubits
+    i_string = "I" * n_qubits
+
+    observable = SparsePauliOp(
+        [replace_str_index(i_string, i, "Z") for i in range(n_qubits - 1, -1, -1)]
+    )
+
+    qubits_per_subcircuit = (n_qubits // 2) + (n_qubits % 2)
+    optimization_seed = 111
+
+    cut_result = automatic_cut(
+        circuit, qubits_per_subcircuit, optimization_seed=optimization_seed
+    )
+
+    individual_subcircuits = cut_result["individual_subcircuits"]
+    subcircuit_labels = cut_result["subcircuit_labels"]
+    coefficients = cut_result["coefficients"]
+    metadata = cut_result["metadata"]
+    qubit_map = metadata["qubit_map"]
+    subobservables = metadata["subobservables"]
+
+    sampler = Sampler(run_options={"shots": shots})
+    # Retrieve results from each partition's subexperiments
+    results = sampler.run(individual_subcircuits).result()
+
+    results_dict = defaultdict(list)
+    for label, res in zip(subcircuit_labels, results.quasi_dists):
+        results_dict[label].append(res)
+
+    reconstructed_counts = reconstruct_distribution(
+        results_dict, coefficients, qubit_map, subobservables
+    )
+
+    estimator = EstimatorV2()
+
+    actual_expval_list = []
+    exact_expval_list = []
+    for i in range(n_qubits):
+        actual_expval = 0
+        for meas, count in reconstructed_counts.items():
+            actual_expval += (-1) ** ((meas >> i) % 2) * count
+        actual_expval_list.append(actual_expval)
+        exact_expval = estimator.run([(circuit, observable.paulis[i])]).result()
+        exact_expval_list.append(exact_expval[0].data.evs)
+
+    return exact_expval_list, actual_expval_list