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Fix Initialize.gates_to_uncompute method #12976

Merged
merged 9 commits into from
Aug 20, 2024
10 changes: 8 additions & 2 deletions qiskit/circuit/library/data_preparation/initializer.py
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
from qiskit.circuit.quantumcircuit import QuantumCircuit
from qiskit.circuit.quantumregister import QuantumRegister
from qiskit.circuit.instruction import Instruction
from qiskit.circuit.library.generalized_gates import Isometry
from .state_preparation import StatePreparation

if typing.TYPE_CHECKING:
Expand Down Expand Up @@ -86,9 +87,14 @@ def gates_to_uncompute(self) -> QuantumCircuit:
"""Call to create a circuit with gates that take the desired vector to zero.

Returns:
Circuit to take ``self.params`` vector to :math:`|{00\\ldots0}\\rangle`
QuantumCircuit: circuit to take ``self.params`` vector to :math:`|{00\\ldots0}\\rangle`
"""
return self._stateprep._gates_to_uncompute()
q = QuantumRegister(self.num_qubits)
circuit = QuantumCircuit(q, name="disentangler")

isom = Isometry(self.params, 0, 0)
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circuit.append(isom, q[:])
return circuit.inverse()

@property
def params(self):
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Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
---
fixes:
- |
Fix a bug that caused the method :meth:`Initialize.gates_to_uncompute()` fail.
8 changes: 8 additions & 0 deletions test/python/circuit/test_initializer.py
Original file line number Diff line number Diff line change
Expand Up @@ -465,6 +465,14 @@ def test_mutating_params(self):
self.assertEqual(decom_circ.data[2].operation.name, "state_preparation")
self.assertEqual(decom_circ.data[2].operation.params, ["0", "0"])

def test_gates_to_uncompute(self):
"""Test the gates_to_uncompute() method."""
desired_vector = [0.5, 0.5, 0.5, 0.5]
initialize = Initialize(desired_vector)
qc = initialize.gates_to_uncompute().inverse()
vec = Statevector(qc)
self.assertTrue(vec == Statevector(desired_vector))


class TestInstructionParam(QiskitTestCase):
"""Test conversion of numpy type parameters."""
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