qiskit.pulse.instructions.Snapshot

class Snapshot(label, snapshot_type='statevector', name=None)

An instruction targeted for simulators, to capture a moment in the simulation.

Create new snapshot.

Parameters

• label (str) – Snapshot label which is used to identify the snapshot in the output.

• snapshot_type (str) – 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 (Optional[str]) – Snapshot name which defaults to label. This parameter is only for display purposes and is not taken into account during comparison.

Raises

PulseError – If snapshot label is invalid.

__init__(label, snapshot_type='statevector', name=None)

Create new snapshot.

Parameters

• label (str) – Snapshot label which is used to identify the snapshot in the output.

• snapshot_type (str) – 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 (Optional[str]) – Snapshot name which defaults to label. This parameter is only for display purposes and is not taken into account during comparison.

Raises

PulseError – If snapshot label is invalid.

Methods

__init__(label[, snapshot_type, name])	Create new snapshot.
append(schedule[, name])	Return a new Schedule with schedule inserted at the maximum time over all channels shared between self and schedule.
assign_parameters(value_dict)	Modify and return self with parameters assigned according to the input.
ch_duration(*channels)	Return duration of the supplied channels in this Instruction.
ch_start_time(*channels)	Return minimum start time for supplied channels.
ch_stop_time(*channels)	Return maximum start time for supplied channels.
draw([dt, style, filename, interp_method, …])	Plot the instruction.
flatten()	Return itself as already single instruction.
insert(start_time, schedule[, name])	Return a new Schedule with schedule inserted within self at start_time.
shift(time[, name])	Return a new schedule shifted forward by time.

Attributes

channel	Return the Channel that this instruction is scheduled on; trivially, a SnapshotChannel.
channels	Returns channels that this schedule uses.
command	The associated command.
duration	Duration of this instruction.
id	Unique identifier for this instruction.
instructions	Iterable for getting instructions from Schedule tree.
label	Label of snapshot.
name	Name of this instruction.
operands	Return instruction operands.
start_time	Relative begin time of this instruction.
stop_time	Relative end time of this instruction.
timeslots	Occupied time slots by this instruction.
type	Type of snapshot.

append(schedule, name=None)

Return a new Schedule with schedule inserted at the maximum time over all channels shared between self and schedule.

Parameters

• schedule (ScheduleComponent) – schedule to be appended

• name (Optional[str]) – Name of the new schedule. Defaults to name of self

Return type

Schedule

assign_parameters(value_dict)

Modify and return self with parameters assigned according to the input.

Parameters

value_dict (Dict[ParameterExpression, Union[ParameterExpression, float, int]]) – A mapping from Parameters to either numeric values or another Parameter expression.

Return type

Instruction

Returns

Self with updated parameters.

ch_duration(*channels)

Return duration of the supplied channels in this Instruction.

Parameters

*channels – Supplied channels

Return type

int

ch_start_time(*channels)

Return minimum start time for supplied channels.

Parameters

*channels – Supplied channels

Return type

int

ch_stop_time(*channels)

Return maximum start time for supplied channels.

Parameters

*channels – Supplied channels

Return type

int

property channel

Return the Channel that this instruction is scheduled on; trivially, a SnapshotChannel.

Return type

SnapshotChannel

property channels

Returns channels that this schedule uses.

Return type

Tuple[Channel]

property command

The associated command. Commands are deprecated, so this method will be deprecated shortly.

Returns

The deprecated command if available.

Return type

Command

draw(dt=1, style=None, filename=None, interp_method=None, scale=1, plot_all=False, plot_range=None, interactive=False, table=True, label=False, framechange=True, channels=None)

Plot the instruction.

Parameters

• dt (float) – Time interval of samples

• style (Optional[SchedStyle]) – A style sheet to configure plot appearance

• filename (Optional[str]) – Name required to save pulse image

• interp_method (Optional[Callable]) – A function for interpolation

• scale (float) – Relative visual scaling of waveform amplitudes

• plot_all (bool) – Plot empty channels

• plot_range (Optional[Tuple[float]]) – A tuple of time range to plot

• interactive (bool) – When set true show the circuit in a new window (this depends on the matplotlib backend being used supporting this)

• table (bool) – Draw event table for supported instructions

• label (bool) – Label individual instructions

• framechange (bool) – Add framechange indicators

• channels (Optional[List[Channel]]) – A list of channel names to plot

Returns

A matplotlib figure object of the pulse schedule

Return type

matplotlib.figure

property duration

Duration of this instruction.

Return type

int

flatten()

Return itself as already single instruction.

Return type

Instruction

property id

Unique identifier for this instruction.

Return type

int

insert(start_time, schedule, name=None)

Return a new Schedule with schedule inserted within self at start_time.

Parameters

• start_time (int) – Time to insert the schedule schedule

• schedule (ScheduleComponent) – Schedule to insert

• name (Optional[str]) – Name of the new schedule. Defaults to name of self

Return type

Schedule

property instructions

Iterable for getting instructions from Schedule tree.

Return type

Tuple[Tuple[int, Instruction]]

property label

Label of snapshot.

Return type

str

property name

Name of this instruction.

Return type

str

property operands

Return instruction operands.

Return type

Tuple

shift(time, name=None)

Return a new schedule shifted forward by time.

Parameters

• time (int) – Time to shift by

• name (Optional[str]) – Name of the new schedule. Defaults to name of self

Return type

Schedule

property start_time

Relative begin time of this instruction.

Return type

int

property stop_time

Relative end time of this instruction.

Return type

int

property timeslots

Occupied time slots by this instruction.

Return type

Dict[Channel, List[Tuple[int, int]]]

property type

Type of snapshot.

Return type

str