Reference
class qiskit.pulse.instructions.Reference(name, *extra_keys)
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
ch_duration
ch_duration(*channels)
Return duration of the supplied channels in this Instruction.
Parameters
*channels (Channel) – Supplied channels
Return type
ch_start_time
ch_start_time(*channels)
Return minimum start time for supplied channels.
Parameters
*channels (Channel) – Supplied channels
Return type
ch_stop_time
ch_stop_time(*channels)
Return maximum start time for supplied channels.
Parameters
*channels (Channel) – Supplied channels
Return type
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
is_parameterized
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