def _try_decompose_into_operations_and_qubits(
val: Any
) -> Tuple[Optional[List['cirq.Operation']], Sequence['cirq.Qid'], Tuple[int,
...]]:
"""Returns the value's decomposition (if any) and the qubits it applies to.
"""
from cirq.protocols.decompose import (decompose_once,
decompose_once_with_qubits)
from cirq import LineQubit, Gate, Operation
if isinstance(val, Gate):
# Gates don't specify qubits, and so must be handled specially.
qid_shape = qid_shape_protocol.qid_shape(val)
qubits = LineQubit.range(len(qid_shape)) # type: Sequence[cirq.Qid]
return decompose_once_with_qubits(val, qubits, None), qubits, qid_shape
if isinstance(val, Operation):
qid_shape = qid_shape_protocol.qid_shape(val)
return decompose_once(val, None), val.qubits, qid_shape
result = decompose_once(val, None)
if result is not None:
qubit_set = set()
qid_shape_dict = defaultdict(lambda: 1) # type: Dict[cirq.Qid, int]
for op in result:
for level, q in zip(qid_shape_protocol.qid_shape(op), op.qubits):
qubit_set.add(q)
qid_shape_dict[q] = max(qid_shape_dict[q], level)
qubits = sorted(qubit_set)
return result, qubits, tuple(qid_shape_dict[q] for q in qubits)
return None, (), ()
def _decompose_and_get_unitary(val: 'cirq.Operation') -> np.ndarray:
"""Try to decompose an `Operation` and return its unitary.
Returns:
If `val` can be decomposed into unitaries, calculate the resulting
unitary and return it. If it doesn't exist, None is returned.
"""
from cirq.protocols.apply_unitary import apply_unitary, ApplyUnitaryArgs
from cirq.protocols.decompose import decompose_once
decomposed_val = decompose_once(val, None)
if decomposed_val is not None:
# Calculate the resulting unitary (if it exists)
n = len(val.qubits)
state = np.eye(1 << n, dtype=np.complex128)
state.shape = (2, ) * (2 * n)
buffer = np.zeros(state.shape, dtype=np.complex128)
qubit_map = {q: i for i, q in enumerate(val.qubits)}
result = state
for op in decomposed_val:
indices = [qubit_map[q] for q in op.qubits]
result = apply_unitary(unitary_value=op,
args=ApplyUnitaryArgs(
state, buffer, indices),
default=None)
if result is None:
return None
if result is buffer:
buffer = state
state = result
if result is not None:
return result.reshape((1 << n, 1 << n))
def has_unitary(val: Any) -> bool:
"""Returns whether the value has a unitary matrix representation.
Returns:
If `val` has a _has_unitary_ method and its result is not
NotImplemented, that result is returned. Otherwise, if `val` is a
cirq.Operation, a decomposition will be attempted and the resulting
unitary will be returned if unitaries exist for all operations of the
decompostion. Otherwise, if the value has a _unitary_ method return if
that has a non-default value. Returns False if neither function exists.
"""
from cirq.protocols.decompose import decompose_once
from cirq import Operation # HACK: Avoids circular dependencies.
getter = getattr(val, '_has_unitary_', None)
result = NotImplemented if getter is None else getter()
# Fallback to decomposition for operations
if result is NotImplemented and isinstance(val, Operation):
decomposed_val = decompose_once(val, None)
if decomposed_val is not None:
result = all(has_unitary(v) for v in decomposed_val)
if result is not NotImplemented:
return result
# No _has_unitary_ function, use _unitary_ instead
return unitary(val, None) is not None
def _try_decompose_into_operations_and_qubits(
val: Any
) -> Tuple[Optional[List['cirq.Operation']], Sequence['cirq.Qid']]:
"""Returns the value's decomposition (if any) and the qubits it applies to.
"""
from cirq.protocols.decompose import (decompose_once,
decompose_once_with_qubits)
from cirq import LineQubit, Gate, Operation
if isinstance(val, Gate):
# Gates don't specify qubits, and so must be handled specially.
qubits = LineQubit.range(val.num_qubits())
return decompose_once_with_qubits(val, qubits, None), qubits
if isinstance(val, Operation):
return decompose_once(val, None), val.qubits
result = decompose_once(val, None)
if result is not None:
return result, sorted({q for op in result for q in op.qubits})
return None, ()
def _decompose_and_get_unitary(
val: Union['cirq.Operation', 'cirq.Gate']) -> np.ndarray:
"""Try to decompose a cirq.Operation or cirq.Gate, and return its unitary
if it exists.
Returns:
If `val` can be decomposed into unitaries, calculate the resulting
unitary and return it. If it doesn't exist, None is returned.
"""
from cirq.protocols.apply_unitary import apply_unitary, ApplyUnitaryArgs
from cirq.protocols.decompose import (decompose_once,
decompose_once_with_qubits)
from cirq import Gate, LineQubit, Operation
if isinstance(val, Operation):
qubits = val.qubits
decomposed_val = decompose_once(val, default=None)
elif isinstance(val, Gate):
# Since gates don't know about qubits, we need to create some
qubits = tuple(LineQubit.range(val.num_qubits()))
decomposed_val = decompose_once_with_qubits(val, qubits, default=None)
if decomposed_val is not None:
# Calculate the resulting unitary (if it exists)
n = len(qubits)
state = np.eye(1 << n, dtype=np.complex128)
state.shape = (2, ) * (2 * n)
buffer = np.zeros(state.shape, dtype=np.complex128)
qubit_map = {q: i for i, q in enumerate(qubits)}
result = state
for op in decomposed_val:
indices = [qubit_map[q] for q in op.qubits]
result = apply_unitary(unitary_value=op,
args=ApplyUnitaryArgs(
state, buffer, indices),
default=None)
if result is None:
return None
if result is buffer:
buffer = state
state = result
if result is not None:
return result.reshape((1 << n, 1 << n))
def has_unitary(val: Any) -> bool:
"""Returns whether the value has a unitary matrix representation.
Returns:
If `val` has a _has_unitary_ method and its result is not
NotImplemented, that result is returned. Otherwise, if `val` is a
cirq.Gate or cirq.Operation, a decomposition is attempted and the
resulting unitary is returned if has_unitary is True for all operations
of the decompostion. Otherwise, if the value has a _unitary_ method
return if that has a non-default value. Returns False if neither
function exists.
"""
from cirq.protocols.decompose import (decompose_once,
decompose_once_with_qubits)
# HACK: Avoids circular dependencies.
from cirq import Gate, Operation, LineQubit
getter = getattr(val, '_has_unitary_', None)
result = NotImplemented if getter is None else getter()
if result is not NotImplemented:
return result
# Fallback to explicit _unitary_
unitary_getter = getattr(val, '_unitary_', None)
if unitary_getter is not None and unitary_getter() is not NotImplemented:
return True
# Fallback to decomposition for gates and operations
if isinstance(val, Gate):
# Since gates don't know about qubits, we need to create some
decomposed_val = decompose_once_with_qubits(val,
LineQubit.range(
val.num_qubits()),
default=None)
if decomposed_val is not None:
return all(has_unitary(v) for v in decomposed_val)
elif isinstance(val, Operation):
decomposed_val = decompose_once(val, default=None)
if decomposed_val is not None:
return all(has_unitary(v) for v in decomposed_val)
# Finally, fallback to full unitary method, including decomposition
return unitary(val, None) is not None
