class Moments(Mapping[MomentsKey, Instruction]):
"""
An ordered mapping of `MomentsKey` or `NoiseMomentsKey` to `Instruction`. The
core data structure that contains instructions, ordering they are inserted in, and
time slices when they occur. `Moments` implements `Mapping` and functions the same as
a read-only dictionary. It is mutable only through the `add()` method.
This data structure is useful to determine a dependency of instructions, such as
printing or optimizing circuit structure, before sending it to a quantum
device. The original insertion order is preserved and can be retrieved via the `values()`
method.
Args:
instructions (Iterable[Instruction], optional): Instructions to initialize self.
Default = None.
Examples:
>>> moments = Moments()
>>> moments.add([Instruction(Gate.H(), 0), Instruction(Gate.CNot(), [0, 1])])
>>> moments.add([Instruction(Gate.H(), 0), Instruction(Gate.H(), 1)])
>>> for i, item in enumerate(moments.items()):
... print(f"Item {i}")
... print(f"\\tKey: {item[0]}")
... print(f"\\tValue: {item[1]}")
...
Item 0
Key: MomentsKey(time=0, qubits=QubitSet([Qubit(0)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(0)]))
Item 1
Key: MomentsKey(time=1, qubits=QubitSet([Qubit(0), Qubit(1)]))
Value: Instruction('operator': CNOT, 'target': QubitSet([Qubit(0), Qubit(1)]))
Item 2
Key: MomentsKey(time=2, qubits=QubitSet([Qubit(0)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(0)]))
Item 3
Key: MomentsKey(time=2, qubits=QubitSet([Qubit(1)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(1)]))
"""
def __init__(self, instructions: Iterable[Instruction] = None):
self._moments: OrderedDict[MomentsKey, Instruction] = OrderedDict()
self._max_times: Dict[Qubit, int] = {}
self._qubits = QubitSet()
self._depth = 0
self._time_all_qubits = -1
self.add(instructions or [])
@property
def depth(self) -> int:
"""int: Get the depth (number of slices) of self."""
return self._depth
@property
def qubit_count(self) -> int:
"""int: Get the number of qubits used across all of the instructions."""
return len(self._qubits)
@property
def qubits(self) -> QubitSet:
"""
QubitSet: Get the qubits used across all of the instructions. The order of qubits is based
on the order in which the instructions were added.
Note:
Don't mutate this object, any changes may impact the behavior of this class and / or
consumers. If you need to mutate this, then copy it via `QubitSet(moments.qubits())`.
"""
return self._qubits
def time_slices(self) -> Dict[int, List[Instruction]]:
"""
Get instructions keyed by time.
Returns:
Dict[int, List[Instruction]]: Key is the time and value is a list of instructions that
occur at that moment in time. The order of instructions is in no particular order.
Note:
This is a computed result over self and can be freely mutated. This is re-computed with
every call, with a computational runtime O(N) where N is the number
of instructions in self.
"""
time_slices = {}
self.sort_moments()
for key, instruction in self._moments.items():
instructions = time_slices.get(key.time, [])
instructions.append(instruction)
time_slices[key.time] = instructions
return time_slices
def add(self, instructions: Iterable[Instruction], noise_index: int = 0) -> None:
"""
Add instructions to self.
Args:
instructions (Iterable[Instruction]): Instructions to add to self. The instruction is
added to the max time slice in which the instruction fits.
"""
for instruction in instructions:
self._add(instruction, noise_index)
def _add(self, instruction: Instruction, noise_index: int = 0) -> None:
operator = instruction.operator
if isinstance(operator, CompilerDirective):
time = self._update_qubit_times(self._qubits)
self._moments[MomentsKey(time, None, MomentType.COMPILER_DIRECTIVE, 0)] = instruction
self._depth = time + 1
self._time_all_qubits = time
elif isinstance(operator, Noise):
self.add_noise(instruction)
else:
qubit_range = instruction.target
time = self._update_qubit_times(qubit_range)
self._moments[
MomentsKey(time, instruction.target, MomentType.GATE, noise_index)
] = instruction
self._qubits.update(instruction.target)
self._depth = max(self._depth, time + 1)
def _update_qubit_times(self, qubits):
qubit_max_times = [self._max_time_for_qubit(qubit) for qubit in qubits] + [
self._time_all_qubits
]
time = max(qubit_max_times) + 1
# Update time for all specified qubits
for qubit in qubits:
self._max_times[qubit] = time
return time
def add_noise(
self, instruction: Instruction, input_type: str = "noise", noise_index: int = 0
) -> None:
qubit_range = instruction.target
time = max(0, *[self._max_time_for_qubit(qubit) for qubit in qubit_range])
if input_type == MomentType.INITIALIZATION_NOISE:
time = 0
while MomentsKey(time, qubit_range, input_type, noise_index) in self._moments:
noise_index = noise_index + 1
self._moments[MomentsKey(time, qubit_range, input_type, noise_index)] = instruction
self._qubits.update(qubit_range)
def sort_moments(self) -> None:
"""
Make the disordered moments in order.
1. Make the readout noise in the end
2. Make the initialization noise at the beginning
"""
# key for NOISE, GATE and GATE_NOISE
key_noise = []
# key for INITIALIZATION_NOISE
key_initialization_noise = []
# key for READOUT_NOISE
key_readout_noise = []
moment_copy = OrderedDict()
sorted_moment = OrderedDict()
for key, instruction in self._moments.items():
moment_copy[key] = instruction
if key.moment_type == MomentType.READOUT_NOISE:
key_readout_noise.append(key)
elif key.moment_type == MomentType.INITIALIZATION_NOISE:
key_initialization_noise.append(key)
else:
key_noise.append(key)
for key in key_initialization_noise:
sorted_moment[key] = moment_copy[key]
for key in key_noise:
sorted_moment[key] = moment_copy[key]
# find the max time in the circuit and make it the time for readout noise
max_time = max(self._depth - 1, 0)
for key in key_readout_noise:
sorted_moment[
MomentsKey(max_time, key.qubits, MomentType.READOUT_NOISE, key.noise_index)
] = moment_copy[key]
self._moments = sorted_moment
def _max_time_for_qubit(self, qubit: Qubit) -> int:
# -1 if qubit is unoccupied because the first instruction will have an index of 0
return self._max_times.get(qubit, -1)
#
# Implement abstract methods, default to calling selfs underlying dictionary
#
def keys(self) -> KeysView[MomentsKey]:
"""Return a view of self's keys."""
return self._moments.keys()
def items(self) -> ItemsView[MomentsKey, Instruction]:
"""Return a view of self's (key, instruction)."""
return self._moments.items()
def values(self) -> ValuesView[Instruction]:
"""Return a view of self's instructions."""
self.sort_moments()
return self._moments.values()
def get(self, key: MomentsKey, default=None) -> Instruction:
"""
Get the instruction in self by key.
Args:
key (MomentsKey): Key of the instruction to fetch.
default (Any, optional): Value to return if `key` is not in `moments`. Default = `None`.
Returns:
Instruction: `moments[key]` if `key` in `moments`, else `default` is returned.
"""
return self._moments.get(key, default)
def __getitem__(self, key):
return self._moments.__getitem__(key)
def __iter__(self):
return self._moments.__iter__()
def __len__(self):
return self._moments.__len__()
def __contains__(self, item):
return self._moments.__contains__(item)
def __eq__(self, other):
if isinstance(other, Moments):
return self._moments == other._moments
return NotImplemented
def __ne__(self, other):
result = self.__eq__(other)
if result is not NotImplemented:
return not result
return NotImplemented
def __repr__(self):
return self._moments.__repr__()
def __str__(self):
return self._moments.__str__()
class Moments(Mapping[MomentsKey, Instruction]):
"""
An ordered mapping of `MomentsKey` to `Instruction`. The core data structure that
contains instructions, ordering they are inserted in, and time slices when they
occur. `Moments` implements `Mapping` and functions the same as a read-only
dictionary. It is mutable only through the `add()` method.
This data structure is useful to determine a dependency of instructions, such as
printing or optimizing circuit structure, before sending it to a quantum
device. The original insertion order is preserved and can be retrieved via the `values()`
method.
Args:
instructions (Iterable[Instruction], optional): Instructions to initialize self.
Default = [].
Examples:
>>> moments = Moments()
>>> moments.add([Instruction(Gate.H(), 0), Instruction(Gate.CNot(), [0, 1])])
>>> moments.add([Instruction(Gate.H(), 0), Instruction(Gate.H(), 1)])
>>> for i, item in enumerate(moments.items()):
... print(f"Item {i}")
... print(f"\\tKey: {item[0]}")
... print(f"\\tValue: {item[1]}")
...
Item 0
Key: MomentsKey(time=0, qubits=QubitSet([Qubit(0)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(0)]))
Item 1
Key: MomentsKey(time=1, qubits=QubitSet([Qubit(0), Qubit(1)]))
Value: Instruction('operator': CNOT, 'target': QubitSet([Qubit(0), Qubit(1)]))
Item 2
Key: MomentsKey(time=2, qubits=QubitSet([Qubit(0)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(0)]))
Item 3
Key: MomentsKey(time=2, qubits=QubitSet([Qubit(1)]))
Value: Instruction('operator': H, 'target': QubitSet([Qubit(1)]))
"""
def __init__(self, instructions: Iterable[Instruction] = []):
self._moments: OrderedDict[MomentsKey, Instruction] = OrderedDict()
self._max_times: Dict[Qubit, int] = {}
self._qubits = QubitSet()
self._depth = 0
self.add(instructions)
@property
def depth(self) -> int:
"""int: Get the depth (number of slices) of self."""
return self._depth
@property
def qubit_count(self) -> int:
"""int: Get the number of qubits used across all of the instructions."""
return len(self._qubits)
@property
def qubits(self) -> QubitSet:
"""
QubitSet: Get the qubits used across all of the instructions. The order of qubits is based
on the order in which the instructions were added.
Note:
Don't mutate this object, any changes may impact the behavior of this class and / or
consumers. If you need to mutate this, then copy it via `QubitSet(moments.qubits())`.
"""
return self._qubits
def time_slices(self) -> Dict[int, List[Instruction]]:
"""
Get instructions keyed by time.
Returns:
Dict[int, List[Instruction]]: Key is the time and value is a list of instructions that
occur at that moment in time. The order of instructions is in no particular order.
Note:
This is a computed result over self and can be freely mutated. This is re-computed with
every call, with a computational runtime O(N) where N is the number
of instructions in self.
"""
time_slices = {}
for key, instruction in self._moments.items():
instructions = time_slices.get(key.time, [])
instructions.append(instruction)
time_slices[key.time] = instructions
return time_slices
def add(self, instructions: Iterable[Instruction]) -> None:
"""
Add instructions to self.
Args:
instructions (Iterable[Instruction]): Instructions to add to self. The instruction
is added to the max time slice in which the instruction fits.
"""
for instruction in instructions:
self._add(instruction)
def _add(self, instruction: Instruction) -> None:
qubit_range = instruction.target
time = max([self._max_time_for_qubit(qubit)
for qubit in qubit_range]) + 1
# Mark all qubits in qubit_range with max_time
for qubit in qubit_range:
self._max_times[qubit] = max(time, self._max_time_for_qubit(qubit))
self._moments[MomentsKey(time, instruction.target)] = instruction
self._qubits.update(instruction.target)
self._depth = max(self._depth, time + 1)
def _max_time_for_qubit(self, qubit: Qubit) -> int:
return self._max_times.get(qubit, -1)
#
# Implement abstract methods, default to calling selfs underlying dictionary
#
def keys(self) -> KeysView[MomentsKey]:
"""Return a view of self's keys."""
return self._moments.keys()
def items(self) -> ItemsView[MomentsKey, Instruction]:
"""Return a view of self's (key, instruction)."""
return self._moments.items()
def values(self) -> ValuesView[Instruction]:
"""Return a view of self's instructions."""
return self._moments.values()
def get(self, key: MomentsKey, default=None) -> Instruction:
"""
Get the instruction in self by key.
Args:
key (MomentsKey): Key of the instruction to fetch.
default (Any, optional): Value to return if `key` is not in `moments`. Default = `None`.
Returns:
Instruction: `moments[key]` if `key` in `moments`, else `default` is returned.
"""
return self._moments.get(key, default)
def __getitem__(self, key):
return self._moments.__getitem__(key)
def __iter__(self):
return self._moments.__iter__()
def __len__(self):
return self._moments.__len__()
def __contains__(self, item):
return self._moments.__contains__(item)
def __eq__(self, other):
if isinstance(other, Moments):
return (self._moments) == (other._moments)
return NotImplemented
def __ne__(self, other):
result = self.__eq__(other)
if result is not NotImplemented:
return not result
return NotImplemented
def __repr__(self):
return self._moments.__repr__()
def __str__(self):
return self._moments.__str__()
