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Reference

qiskit.pulse.instructions.Reference(name, *extra_keys)GitHub(opens in a new tab)

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(opens in a new tab)) – Name of subroutine.
  • extra_keys (str(opens in a new tab)) – 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

= ','

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 = '

= ':

= '::'

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(opens in a new tab) | 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 (Channel) – Supplied channels

Return type

int(opens in a new tab)

ch_start_time

ch_start_time(*channels)

Return minimum start time for supplied channels.

Parameters

*channels (Channel) – Supplied channels

Return type

int(opens in a new tab)

ch_stop_time

ch_stop_time(*channels)

Return maximum start time for supplied channels.

Parameters

*channels (Channel) – Supplied channels

Return type

int(opens in a new tab)

insert

insert(start_time, schedule, name=None)

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

Parameters

  • start_time (int(opens in a new tab)) – Time to insert the schedule schedule
  • schedule (Union['Schedule', 'Instruction']) – Schedule or instruction to insert
  • name (str(opens in a new tab) | 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(opens in a new tab)

shift

shift(time, name=None)

Return a new schedule shifted forward by time.

Parameters

Returns

The shifted schedule.

Return type

Schedule

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