def create_qsvt_circuit(num_qubits, num_ancillas, add_measurements,
block_encoding, block_encoding_inv, angles):
qsvt_circuit = Circuit()
if num_ancillas != 1:
raise NotImplementedError(
"The general QSVT circuit generation is not yet implemented!")
else:
qubits = list(range(1, num_qubits + 1))
# Quanutm Singular Value Transformation
qsvt_circuit.h(0)
for i in range(0, len(angles)):
if i % 2 == 0:
qsvt_circuit.add_circuit(block_encoding, target=qubits)
else:
qsvt_circuit.add_circuit(block_encoding_inv, target=qubits)
# qsvt_circuit.x(1)
qsvt_circuit.cnot(1, 0)
qsvt_circuit.rz(0, -2 * angles[i])
# For debugging purposes to get the global phase right replace the above line with the following:
# qsvt_circuit.u1(-angles[i],0)
# qsvt_circuit.x(0)
# qsvt_circuit.u1(angles[i],0)
# qsvt_circuit.x(0)
qsvt_circuit.cnot(1, 0)
# qsvt_circuit.x(1)
qsvt_circuit.h(0)
return qsvt_circuit
def grover_iterator(A, flag_qubit, qubits=None, use_explicit_unitary=False):
"""
Function to implement the Grover iterator Q=A R_0 A* R_B.
Args:
A: Circuit defining the unitary A
flag_qubit: Specifies which of the qubits A acts on labels the good/bad subspace.
Must be an element of qubits (if passed) or A.qubits.
qubits: list of qubits on which to apply the gates (including the flag_qubit).
If qubits is different from A.qubits, A is applied to qubits instead.
use_explicit_unitary: Flag to specify that we should implement R_0 using using a custom
gate defined by the unitary diag(-1,1,...,1). Default is False.
"""
# If no qubits are passed, apply the gates to the targets of A
if qubits is None:
qubits = A.qubits
else:
# If qubits are passed, make sure it's the right number to remap from A.
if len(qubits) != len(A.qubits):
raise ValueError(
"Number of desired target qubits differs from number of targets in A"
.format(flag_qubit=repr(flag_qubit)))
# Verify that flag_qubit is one of the qubits on which A acts, or one of the user defined qubits
if flag_qubit not in qubits:
raise ValueError(
"flag_qubit {flag_qubit} is not in targets of A".format(
flag_qubit=repr(flag_qubit)))
# Instantiate the circuit
circ = Circuit()
# Apply -R_B to the flag qubit
circ.minus_R_B(flag_qubit)
# Apply A^\dagger. Use target mapping if different qubits are specified
circ.add_circuit(A.adjoint(), target=qubits)
# Apply -R_0
circ.minus_R_zero(qubits, use_explicit_unitary)
# Apply A, mapping targets if desired.
circ.add_circuit(A, target=qubits)
return circ
def job_factory(matrix, num_shots, shots_multiplier, add_measurements):
if matrix is None:
raise NotImplementedError("The matrix is Not specified")
num_qubits = matrix["qubits"]
num_ancillas = matrix["ancillas"]
if num_ancillas != 1:
raise NotImplementedError(
"The general HHL circuit generation is not yet implemented!")
# Build block-encoding of A
block_encoding = Circuit()
HHLJob.list_to_circuit(matrix["circuit"], block_encoding)
# block_encoding.draw()
# Angles describing the polynomial inverting A
angles = matrix["angles"]
# Quanutm Singular Value Transformation
qsvt_circuit = HHLJob.create_qsvt_circuit(
num_qubits,
num_ancillas,
add_measurements,
block_encoding.adjoint(),
block_encoding,
angles,
)
# For debug purposes
# reorder = QuantumCircuit(num_qubits+1)
# reorder.swap(0,3)
# reorder.swap(1,2)
# Debugging the circuit
# print(block_encoding)
# print_unitary=reorder.compose(block_encoding,qubits=list(range(1,num_qubits + 1))).extend(reorder)
# #job execution and getting the unitary matrix of the circuit
# job = execute(print_unitary, BasicAer.get_backend('unitary_simulator'))
# print(DataFrame(job.result().get_unitary(print_unitary, decimals=2)))
# raise NotImplementedError("Stop now")
# Debugging the circuit
# print(qsvt_circuit)
# print_unitary=reorder.combine(qsvt_circuit).extend(reorder)
# # job execution and getting the unitary matrix of the circuit
# job = execute(print_unitary, BasicAer.get_backend('unitary_simulator'))
# print(DataFrame(job.result().get_unitary(print_unitary, decimals=2)))
used_qubits = num_qubits - num_ancillas
for m_idx in range(shots_multiplier):
for basis_vec in range(0, 2**used_qubits):
instance_circuit = Circuit()
# Here we assume that there is a single ancilla
instance_circuit.x(1)
for i in range(used_qubits):
if basis_vec % 2**(i + 1) >= 2**i:
instance_circuit.x(num_qubits - i)
instance_circuit.add_circuit(qsvt_circuit)
yield HHLJob(
instance_circuit,
num_qubits,
num_ancillas,
basis_vec,
num_shots,
m_idx,
add_measurements,
)
