Source code for qiskit.pulse.instructions.snapshot

# This code is part of Qiskit.
# (C) Copyright IBM 2019.
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""A simulator instruction to capture output within a simulation. The types of snapshot
instructions available are determined by the simulator being used.
from typing import Optional, Tuple

from qiskit.pulse.channels import SnapshotChannel
from qiskit.pulse.exceptions import PulseError
from qiskit.pulse.instructions.instruction import Instruction

[docs]class Snapshot(Instruction): """An instruction targeted for simulators, to capture a moment in the simulation.""" def __init__(self, label: str, snapshot_type: str = "statevector", name: Optional[str] = None): """Create new snapshot. Args: label: Snapshot label which is used to identify the snapshot in the output. snapshot_type: Type of snapshot, e.g., “state” (take a snapshot of the quantum state). The types of snapshots offered are defined by the simulator used. name: Snapshot name which defaults to ``label``. This parameter is only for display purposes and is not taken into account during comparison. """ self._channel = SnapshotChannel() if name is None: name = label super().__init__(operands=(label, snapshot_type), name=name) def _validate(self): """Called after initialization to validate instruction data. Raises: PulseError: If snapshot label is invalid. """ if not isinstance(self.label, str): raise PulseError("Snapshot label must be a string.") @property def label(self) -> str: """Label of snapshot.""" return self.operands[0] @property def type(self) -> str: """Type of snapshot.""" return self.operands[1] @property def channel(self) -> SnapshotChannel: """Return the :py:class:`~qiskit.pulse.channels.Channel` that this instruction is scheduled on; trivially, a ``SnapshotChannel``. """ return self._channel @property def channels(self) -> Tuple[SnapshotChannel]: """Returns the channels that this schedule uses.""" return (,) @property def duration(self) -> int: """Duration of this instruction.""" return 0
[docs] def is_parameterized(self) -> bool: """Return True iff the instruction is parameterized.""" return False