def _decompose_(self, qubits: Sequence['cirq.Qid']) -> 'cirq.OP_TREE':
x0, x1, x2, x3 = self._diag_angles_radians
q0, q1 = qubits
yield common_gates.ZPowGate(exponent=x2 / np.pi).on(q0)
yield common_gates.ZPowGate(exponent=x1 / np.pi).on(q1)
yield common_gates.CZPowGate(exponent=(x3 - (x1 + x2)) / np.pi).on(
q0, q1)
yield common_gates.XPowGate().on_each(q0, q1)
yield common_gates.CZPowGate(exponent=x0 / np.pi).on(q0, q1)
yield common_gates.XPowGate().on_each(q0, q1)
def _decompose_(self, qubits):
a, b = qubits
yield common_gates.CNOT(a, b)
yield common_gates.H(a)
yield common_gates.CNOT(b, a)
yield common_gates.ZPowGate(exponent=self._exponent / 2,
global_shift=self.global_shift).on(a)
yield common_gates.CNOT(b, a)
yield common_gates.ZPowGate(exponent=-self._exponent / 2,
global_shift=-self.global_shift).on(a)
yield common_gates.H(a)
yield common_gates.CNOT(a, b)
def _strat_act_on_stabilizer_ch_form_from_single_qubit_decompose(
val: Any, args: 'cirq.ActOnStabilizerCHFormArgs') -> bool:
if num_qubits(val) == 1:
if not has_unitary(val):
return NotImplemented
u = unitary(val)
clifford_gate = SingleQubitCliffordGate.from_unitary(u)
if clifford_gate is not None:
# Gather the effective unitary applied so as to correct for the
# global phase later.
final_unitary = np.eye(2)
for axis, quarter_turns in clifford_gate.decompose_rotation():
gate = None # type: Optional[cirq.Gate]
if axis == pauli_gates.X:
gate = common_gates.XPowGate(exponent=quarter_turns / 2)
assert gate._act_on_(args)
elif axis == pauli_gates.Y:
gate = common_gates.YPowGate(exponent=quarter_turns / 2)
assert gate._act_on_(args)
else:
assert axis == pauli_gates.Z
gate = common_gates.ZPowGate(exponent=quarter_turns / 2)
assert gate._act_on_(args)
final_unitary = np.matmul(unitary(gate), final_unitary)
# Find the entry with the largest magnitude in the input unitary.
k = max(np.ndindex(*u.shape), key=lambda t: abs(u[t]))
# Correct the global phase that wasn't conserved in the above
# decomposition.
args.state.omega *= u[k] / final_unitary[k]
return True
return NotImplemented
def controlled(
self,
num_controls: int = None,
control_values: Optional[Sequence[Union[int, Collection[int]]]] = None,
control_qid_shape: Optional[Tuple[int, ...]] = None,
) -> raw_types.Gate:
"""Returns a controlled `ZPowGate` with two additional controls.
The `controlled` method of the `Gate` class, of which this class is a
child, returns a `ControlledGate` with `sub_gate = self`. This method
overrides this behavior to return a `ControlledGate` with
`sub_gate = ZPowGate`.
"""
if num_controls == 0:
return self
return controlled_gate.ControlledGate(
controlled_gate.ControlledGate(
common_gates.ZPowGate(exponent=self._exponent,
global_shift=self._global_shift),
num_controls=2,
),
num_controls=num_controls,
control_values=control_values,
control_qid_shape=control_qid_shape,
)
def _x(self, g: common_gates.XPowGate, axis: int):
exponent = g.exponent
if exponent % 2 != 0:
if exponent % 0.5 != 0.0:
raise ValueError('Y exponent must be half integer') # coverage: ignore
self._h(common_gates.H, axis)
self._z(common_gates.ZPowGate(exponent=exponent), axis)
self._h(common_gates.H, axis)
self.state.omega *= _phase(g)
def _strat_act_on_clifford_tableau_from_single_qubit_decompose(
val: Any, args: 'cirq.ActOnCliffordTableauArgs', qubits: Sequence['cirq.Qid']
) -> bool:
if num_qubits(val) == 1:
if not has_unitary(val):
return NotImplemented
u = unitary(val)
clifford_gate = SingleQubitCliffordGate.from_unitary(u)
if clifford_gate is not None:
for axis, quarter_turns in clifford_gate.decompose_rotation():
if axis == pauli_gates.X:
common_gates.XPowGate(exponent=quarter_turns / 2)._act_on_(args, qubits)
elif axis == pauli_gates.Y:
common_gates.YPowGate(exponent=quarter_turns / 2)._act_on_(args, qubits)
else:
assert axis == pauli_gates.Z
common_gates.ZPowGate(exponent=quarter_turns / 2)._act_on_(args, qubits)
return True
return NotImplemented
def __pow__(self: '_PauliZ',
exponent: 'cirq.TParamVal') -> common_gates.ZPowGate:
return common_gates.ZPowGate(
exponent=exponent) if exponent != 1 else _PauliZ()
def _phase_flip_Z() -> common_gates.ZPowGate:
"""
Returns a cirq.Z which corresponds to a guaranteed phase flip.
"""
return common_gates.ZPowGate()
def _decompose_(self, qubits):
yield common_gates.ZPowGate(exponent=self.exponent)(qubits[0])
yield common_gates.ZPowGate(exponent=self.exponent)(qubits[1])
yield common_gates.CZPowGate(exponent=-2 * self.exponent,
global_shift=-self.global_shift / 2)(
qubits[0], qubits[1])
def __pow__(self: '_PauliZ',
exponent: value.TParamVal) -> common_gates.ZPowGate:
return common_gates.ZPowGate(exponent=exponent)
def __pow__(self: '_PauliZ',
exponent: Union[sympy.Basic, float]) -> common_gates.ZPowGate:
return common_gates.ZPowGate(exponent=exponent)
