Reference
class Reference(name, *extra_keys)
Bases: qiskit.pulse.instructions.instruction.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.
Methods
append
Reference.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 (
Optional[str]) – 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
Reference.ch_duration(*channels)
Return duration of the supplied channels in this Instruction.
Parameters
*channels – Supplied channels
Return type
int
ch_start_time
Reference.ch_start_time(*channels)
Return minimum start time for supplied channels.
Parameters
*channels – Supplied channels
Return type
int
ch_stop_time
Reference.ch_stop_time(*channels)
Return maximum start time for supplied channels.
Parameters
*channels – Supplied channels
Return type
int
draw
Reference.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
insert
Reference.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 (
Optional[str]) – 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
Reference.is_parameterized()
Return True iff the instruction is parameterized.
Return type
bool
shift
Reference.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
Returns
The shifted schedule.
Return type
Attributes
channels
duration
id
Unique identifier for this instruction.
Return type
int
instructions
key_delimiter
Default value: ','
name
Name of this instruction.
Return type
str
operands
Return instruction operands.
Return type
Tuple
parameters
Parameters which determine the instruction behavior.
Return type
Set
ref_keys
Returns unique key of the subroutine.
Return type
Tuple[str, ...]
scope_delimiter
Default value: '::'
start_time
Relative begin time of this instruction.
Return type
int
stop_time
Relative end time of this instruction.
Return type
int