def with_operations(self, *contents: 'cirq.OP_TREE') -> 'cirq.Moment':
"""Returns a new moment with the given contents added.
Args:
contents: New operations to add to this moment.
Returns:
The new moment.
"""
from cirq.ops import op_tree
operations = list(self._operations)
qubits = set(self._qubits)
for op in op_tree.flatten_to_ops(contents):
if any(q in qubits for q in op.qubits):
raise ValueError('Overlapping operations: {}'.format(op))
operations.append(op)
qubits.update(op.qubits)
# Use private variables to facilitate a quick copy.
m = Moment()
m._operations = tuple(operations)
m._qubits = frozenset(qubits)
m._qubit_to_op = self._qubit_to_op.copy()
for op in operations:
for q in op.qubits:
m._qubit_to_op[q] = op
return m
def __init__(self, *contents: 'cirq.OP_TREE') -> None:
"""Constructs a moment with the given operations.
Args:
operations: The operations applied within the moment.
Will be flattened and frozen into a tuple before storing.
Raises:
ValueError: A qubit appears more than once.
"""
from cirq.ops import op_tree
self._operations = tuple(op_tree.flatten_to_ops(contents))
# An internal dictionary to support efficient operation access by qubit.
self._qubit_to_op: Dict['cirq.Qid', 'cirq.Operation'] = {}
for op in self.operations:
for q in op.qubits:
# Check that operations don't overlap.
if q in self._qubit_to_op:
raise ValueError('Overlapping operations: {}'.format(
self.operations))
self._qubit_to_op[q] = op
self._qubits = frozenset(self._qubit_to_op.keys())
def _decompose_into_cliffords(op: 'cirq.Operation') -> List['cirq.Operation']:
# An operation that can be ignored?
if isinstance(op, global_phase_op.GlobalPhaseOperation):
return []
# Already a known Clifford?
if isinstance(op.gate, (clifford_gate.SingleQubitCliffordGate,
pauli_interaction_gate.PauliInteractionGate)):
return [op]
# Specifies a decomposition into Cliffords?
v = getattr(op, '_decompose_into_clifford_', None)
if v is not None:
result = v()
if result is not None and result is not NotImplemented:
return list(op_tree.flatten_to_ops(result))
# Specifies a decomposition that happens to contain only Cliffords?
decomposed = protocols.decompose_once(op, None)
if decomposed is not None:
return [
out for sub_op in decomposed
for out in _decompose_into_cliffords(sub_op)
]
raise TypeError(f'Operation is not a known Clifford and did not decompose '
f'into known Cliffords: {op!r}')
def __init__(self, *contents: 'cirq.OP_TREE') -> None:
"""Constructs a moment with the given operations.
Args:
contents: The operations applied within the moment.
Will be flattened and frozen into a tuple before storing.
Raises:
ValueError: A qubit appears more than once.
"""
self._operations = tuple(op_tree.flatten_to_ops(contents))
# An internal dictionary to support efficient operation access by qubit.
self._qubit_to_op: Dict['cirq.Qid', 'cirq.Operation'] = {}
for op in self.operations:
for q in op.qubits:
# Check that operations don't overlap.
if q in self._qubit_to_op:
raise ValueError(
f'Overlapping operations: {self.operations}')
self._qubit_to_op[q] = op
self._qubits = frozenset(self._qubit_to_op.keys())
self._measurement_key_objs: Optional[
AbstractSet['cirq.MeasurementKey']] = None
self._control_keys: Optional[FrozenSet['cirq.MeasurementKey']] = None
def validate(self, circuit_or_optree: Union['cirq.AbstractCircuit', op_tree.OP_TREE]) -> bool:
"""Validates gates forming `circuit_or_optree` should be contained in Gateset.
Args:
circuit_or_optree: The `cirq.Circuit` or `cirq.OP_TREE` to validate.
"""
# To avoid circular import.
from cirq.circuits import circuit
optree = circuit_or_optree
if isinstance(circuit_or_optree, circuit.AbstractCircuit):
optree = circuit_or_optree.all_operations()
return all(self._validate_operation(op) for op in op_tree.flatten_to_ops(optree))
def __sub__(self, other: 'cirq.OP_TREE') -> 'cirq.Moment':
must_remove = set(op_tree.flatten_to_ops(other))
new_ops = []
for op in self.operations:
if op in must_remove:
must_remove.remove(op)
else:
new_ops.append(op)
if must_remove:
raise ValueError(f"Subtracted missing operations from a moment.\n"
f"Missing operations: {must_remove!r}\n"
f"Moment: {self!r}")
return Moment(new_ops)
def __init__(self, *contents: 'cirq.OP_TREE') -> None:
"""Constructs a moment with the given operations.
Args:
operations: The operations applied within the moment.
Will be flattened and frozen into a tuple before storing.
Raises:
ValueError: A qubit appears more than once.
"""
from cirq.ops import op_tree
self._operations = tuple(op_tree.flatten_to_ops(contents))
# Check that operations don't overlap.
affected_qubits = [q for op in self.operations for q in op.qubits]
self._qubits = frozenset(affected_qubits)
if len(affected_qubits) != len(self._qubits):
raise ValueError(
'Overlapping operations: {}'.format(self.operations))
def with_operations(self, *contents: 'cirq.OP_TREE') -> 'cirq.Moment':
"""Returns a new moment with the given contents added.
Args:
*contents: New operations to add to this moment.
Returns:
The new moment.
Raises:
ValueError: If the contents given overlaps a current operation in the moment.
"""
flattened_contents = tuple(op_tree.flatten_to_ops(contents))
m = Moment()
# Use private variables to facilitate a quick copy.
m._qubit_to_op = self._qubit_to_op.copy()
qubits = set(self._qubits)
for op in flattened_contents:
if any(q in qubits for q in op.qubits):
raise ValueError(f'Overlapping operations: {op}')
qubits.update(op.qubits)
for q in op.qubits:
m._qubit_to_op[q] = op
m._qubits = frozenset(qubits)
m._operations = self._operations + flattened_contents
m._sorted_operations = None
m._measurement_key_objs = self._measurement_key_objs_().union(
set(
itertools.chain(*(protocols.measurement_key_objs(op)
for op in flattened_contents))))
m._control_keys = self._control_keys_().union(
set(
itertools.chain(*(protocols.control_keys(op)
for op in flattened_contents))))
return m
def conjugated_by(self, clifford: 'cirq.OP_TREE') -> 'PauliString':
r"""Returns the Pauli string conjugated by a clifford operation.
The product-of-Paulis $P$ conjugated by the Clifford operation $C$ is
$$
C^\dagger P C
$$
For example, conjugating a +Y operation by an S operation results in a
+X operation (as opposed to a -X operation).
In a circuit diagram where `P` is a pauli string observable immediately
after a Clifford operation `C`, the pauli string `P.conjugated_by(C)` is
the equivalent pauli string observable just before `C`.
--------------------------C---P---
= ---C---P------------------------
= ---C---P---------C^-1---C-------
= ---C---P---C^-1---------C-------
= --(C^-1 · P · C)--------C-------
= ---P.conjugated_by(C)---C-------
Analogously, a Pauli product P can be moved from before a Clifford C in
a circuit diagram to after the Clifford C by conjugating P by the
inverse of C:
---P---C---------------------------
= -----C---P.conjugated_by(C^-1)---
Args:
clifford: The Clifford operation to conjugate by. This can be an
individual operation, or a tree of operations.
Note that the composite Clifford operation defined by a sequence
of operations is equivalent to a circuit containing those
operations in the given order. Somewhat counter-intuitively,
this means that the operations in the sequence are conjugated
onto the Pauli string in reverse order. For example,
`P.conjugated_by([C1, C2])` is equivalent to
`P.conjugated_by(C2).conjugated_by(C1)`.
Examples:
>>> a, b = cirq.LineQubit.range(2)
>>> print(cirq.X(a).conjugated_by(cirq.CZ(a, b)))
X(0)*Z(1)
>>> print(cirq.X(a).conjugated_by(cirq.S(a)))
-Y(0)
>>> print(cirq.X(a).conjugated_by([cirq.H(a), cirq.CNOT(a, b)]))
Z(0)*X(1)
Returns:
The Pauli string conjugated by the given Clifford operation.
"""
pauli_map = dict(self._qubit_pauli_map)
should_negate = False
for op in list(op_tree.flatten_to_ops(clifford))[::-1]:
if pauli_map.keys().isdisjoint(set(op.qubits)):
continue
for clifford_op in _decompose_into_cliffords(op)[::-1]:
if pauli_map.keys().isdisjoint(set(clifford_op.qubits)):
continue
should_negate ^= PauliString._pass_operation_over(
pauli_map, clifford_op, False)
coef = -self._coefficient if should_negate else self.coefficient
return PauliString(qubit_pauli_map=pauli_map, coefficient=coef)
