def mcu3(self, theta, phi, lam, control_qubits, target_qubit):
"""
Apply Multiple-Controlled U3 gate
Args:
theta: angle theta
phi: angle phi
lam: angle lambda
control_qubits: The list of control qubits
target_qubit: The target qubit
"""
if isinstance(target_qubit, QuantumRegister) and len(target_qubit) == 1:
target_qubit = target_qubit[0]
temp = []
self._check_qargs(control_qubits)
temp += control_qubits
self._check_qargs([target_qubit])
temp.append(target_qubit)
self._check_dups(temp)
n_c = len(control_qubits)
if n_c == 1: # cu3
apply_cu3(self, theta, phi, lam, control_qubits[0], target_qubit)
else:
_apply_mcu3(self, theta, phi, lam, control_qubits, target_qubit)
def mcu3(self, theta, phi, lam, control_qubits, target_qubit):
"""
Apply Multiple-Controlled U3 gate
Args:
theta: angle theta
phi: angle phi
lam: angle lambda
control_qubits: The list of control qubits
target_qubit: The target qubit
"""
if isinstance(target_qubit, QuantumRegister) and len(target_qubit) == 1:
target_qubit = target_qubit[0]
temp = []
for qubit in control_qubits:
try:
self._check_qubit(qubit)
except AttributeError as e: # TODO Temporary, _check_qubit may not exist
logger.debug(str(e))
temp.append(qubit)
try:
self._check_qubit(target_qubit)
except AttributeError as e: # TODO Temporary, _check_qubit may not exist
logger.debug(str(e))
temp.append(target_qubit)
self._check_dups(temp)
n_c = len(control_qubits)
if n_c == 1: # cu3
apply_cu3(self, theta, phi, lam, control_qubits[0], target_qubit)
else:
_apply_mcu3(self, theta, phi, lam, control_qubits, target_qubit)
def __init__(self, theta, phi, lam, ctls, tgt, circ=None):
"""Create new MCU3 gate."""
self._ctl_bits = ctls
self._tgt_bits = tgt
self._theta = theta
self._phi = phi
self._lambda = lam
qubits = [v for v in ctls] + [tgt]
n_c = len(ctls)
super(MCU3Gate, self).__init__("mcu3", (theta, phi, lam, n_c), qubits,
circ)
if n_c == 1: # cx
apply_cu3(circ, theta, phi, lam, ctls[0], tgt)
else:
self.apply_mcu3(theta, phi, lam, ctls, tgt, circ)
def _apply_mcu3(circuit, theta, phi, lam, ctls, tgt):
"""Apply multi-controlled u3 gate from ctls to tgt with angles theta,
phi, lam."""
n = len(ctls)
gray_code = list(GrayCode(n).generate_gray())
last_pattern = None
theta_angle = theta * (1 / (2**(n - 1)))
phi_angle = phi * (1 / (2**(n - 1)))
lam_angle = lam * (1 / (2**(n - 1)))
for pattern in gray_code:
if not '1' in pattern:
continue
if last_pattern is None:
last_pattern = pattern
#find left most set bit
lm_pos = list(pattern).index('1')
#find changed bit
comp = [i != j for i, j in zip(pattern, last_pattern)]
if True in comp:
pos = comp.index(True)
else:
pos = None
if pos is not None:
if pos != lm_pos:
circuit.cx(ctls[pos], ctls[lm_pos])
else:
indices = [i for i, x in enumerate(pattern) if x == '1']
for idx in indices[1:]:
circuit.cx(ctls[idx], ctls[lm_pos])
#check parity
if pattern.count('1') % 2 == 0:
#inverse
apply_cu3(circuit, -theta_angle, phi_angle, lam_angle,
ctls[lm_pos], tgt)
else:
apply_cu3(circuit, theta_angle, phi_angle, lam_angle, ctls[lm_pos],
tgt)
last_pattern = pattern