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 _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 `XPowGate` 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 = XPowGate`.
"""
if num_controls == 0:
return self
return controlled_gate.ControlledGate(
controlled_gate.ControlledGate(
common_gates.XPowGate(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 _h(self, g: common_gates.HPowGate, axis: int):
exponent = g.exponent
if exponent % 2 == 0:
return
if exponent % 1 != 0:
raise ValueError('H exponent must be integer') # coverage: ignore
self._y(common_gates.YPowGate(exponent=0.5), axis)
self._x(common_gates.XPowGate(), axis)
def _value_equality_values_(self):
if self.phase_exponent == 0:
return common_gates.XPowGate(
exponent=self._exponent,
global_shift=self._global_shift)._value_equality_values_()
if self.phase_exponent == 0.5:
return common_gates.YPowGate(
exponent=self._exponent,
global_shift=self._global_shift)._value_equality_values_()
return self.phase_exponent, self._canonical_exponent, self._global_shift
def _act_on_(self, sim_state: 'cirq.SimulationStateBase',
qubits: Sequence['cirq.Qid']):
if len(qubits) != 1:
return NotImplemented
from cirq.sim import simulation_state
if (isinstance(sim_state, simulation_state.SimulationState)
and not sim_state.can_represent_mixed_states):
result = sim_state._perform_measurement(qubits)[0]
gate = common_gates.XPowGate(
dimension=self.dimension)**(self.dimension - result)
protocols.act_on(gate, sim_state, qubits)
return True
return NotImplemented
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: '_PauliX',
exponent: 'cirq.TParamVal') -> common_gates.XPowGate:
return common_gates.XPowGate(
exponent=exponent) if exponent != 1 else _PauliX()
def _bit_flip_X() -> common_gates.XPowGate:
"""
Returns a cirq.X with guarantees a bit flip.
"""
return common_gates.XPowGate()
def __pow__(self: '_PauliX',
exponent: value.TParamVal) -> common_gates.XPowGate:
return common_gates.XPowGate(exponent=exponent)
def _decompose_(self, qubits: Tuple['cirq.Qid', ...]) -> 'cirq.OP_TREE':
yield common_gates.XPowGate(exponent=0.5).on_each(*qubits)
yield ZZPowGate(exponent=self.exponent, global_shift=self.global_shift)(*qubits)
yield common_gates.XPowGate(exponent=-0.5).on_each(*qubits)
def __pow__(self: '_PauliX',
exponent: Union[sympy.Basic, float]) -> common_gates.XPowGate:
return common_gates.XPowGate(exponent=exponent)
