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Reference

class qiskit.pulse.instructions.Reference(name, *extra_keys)

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Bases: Instruction

Pulse compiler directive that refers to a subroutine.

If a pulse program uses the same subset of instructions multiple times, then using the Reference class may significantly reduce the memory footprint of the program. This instruction only stores the set of strings to identify the subroutine.

The actual pulse program can be stored in the ScheduleBlock.references of the ScheduleBlock that this reference instruction belongs to.

You can later assign schedules with the ScheduleBlock.assign_references() method. This allows you to build the main program without knowing the actual subroutine, that is supplied at a later time.

Create new reference.

Parameters

  • name (str) – Name of subroutine.
  • extra_keys (str) – Optional. A set of string keys that may be necessary to refer to a particular subroutine. For example, when we use “sx” as a name to refer to the subroutine of an sx pulse, this name might be used among schedules for different qubits. In this example, you may specify “q0” in the extra keys to distinguish the sx schedule for qubit 0 from others. The user can use an arbitrary number of extra string keys to uniquely determine the subroutine.

Attributes

channels

Returns the channels that this schedule uses.

duration

Duration of this instruction.

id

Unique identifier for this instruction.

instructions

Iterable for getting instructions from Schedule tree.

key_delimiter

Default value: ','

name

Name of this instruction.

operands

Return instruction operands.

parameters

Parameters which determine the instruction behavior.

ref_keys

Returns unique key of the subroutine.

scope_delimiter

Default value: '::'

start_time

Relative begin time of this instruction.

stop_time

Relative end time of this instruction.


Methods

append

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 (Union['Schedule', 'Instruction']) – Schedule or instruction to be appended
  • name (str | None) – Name of the new schedule. Defaults to name of self

Returns

A new schedule with schedule a this instruction at t=0.

Return type

Schedule

ch_duration

ch_duration(*channels)

Return duration of the supplied channels in this Instruction.

Parameters

*channels (List[Channel]) – Supplied channels

Return type

int

ch_start_time

ch_start_time(*channels)

Return minimum start time for supplied channels.

Parameters

*channels (List[Channel]) – Supplied channels

Return type

int

ch_stop_time

ch_stop_time(*channels)

Return maximum start time for supplied channels.

Parameters

*channels (List[Channel]) – Supplied channels

Return type

int

draw

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.

Deprecated since version 0.23.0

The method qiskit.pulse.instructions.instruction.Instruction.draw() is deprecated as of qiskit-terra 0.23.0. It will be removed no earlier than 3 months after the release date. No direct alternative is being provided to drawing individual pulses. But, instructions can be visualized as part of a complete schedule using qiskit.visualization.pulse_drawer.

Parameters

  • dt (float) – Time interval of samples
  • style (Optional[SchedStyle]) – A style sheet to configure plot appearance
  • filename (str | None) – Name required to save pulse image
  • interp_method (Callable | None) – A function for interpolation
  • scale (float) – Relative visual scaling of waveform amplitudes
  • plot_all (bool) – Plot empty channels
  • plot_range (Tuple[float] | None) – 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 (List[Channel] | None) – A list of channel names to plot

Returns

A matplotlib figure object of the pulse schedule

Return type

matplotlib.figure

insert

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 (Union['Schedule', 'Instruction']) – Schedule or instruction to insert
  • name (str | None) – Name of the new schedule. Defaults to name of self

Returns

A new schedule with schedule inserted with this instruction at t=0.

Return type

Schedule

is_parameterized

is_parameterized()

Return True iff the instruction is parameterized.

Return type

bool

shift

shift(time, name=None)

Return a new schedule shifted forward by time.

Parameters

  • time (int) – Time to shift by
  • name (str | None) – Name of the new schedule. Defaults to name of self

Returns

The shifted schedule.

Return type

Schedule

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