Schedule

class Schedule(*schedules, name=None, metadata=None)

Bases: object

A quantum program schedule with exact time constraints for its instructions, operating over all input signal channels and supporting special syntaxes for building.

Pulse program representation for the original Qiskit Pulse model [1]. Instructions are not allowed to overlap in time on the same channel. This overlap constraint is immediately evaluated when a new instruction is added to the Schedule object.

It is necessary to specify the absolute start time and duration for each instruction so as to deterministically fix its execution time.

The Schedule program supports some syntax sugar for easier programming.

• Appending an instruction to the end of a channel

sched = Schedule()
sched += Play(Gaussian(160, 0.1, 40), DriveChannel(0))

• Appending an instruction shifted in time by a given amount

sched = Schedule()
sched += Play(Gaussian(160, 0.1, 40), DriveChannel(0)) << 30

• Merge two schedules

sched1 = Schedule()
sched1 += Play(Gaussian(160, 0.1, 40), DriveChannel(0))

sched2 = Schedule()
sched2 += Play(Gaussian(160, 0.1, 40), DriveChannel(1))
sched2 = sched1 | sched2

A PulseError is immediately raised when the overlap constraint is violated.

In the schedule representation, we cannot parametrize the duration of instructions. Thus we need to create a new schedule object for each duration. To parametrize an instruction’s duration, the ScheduleBlock representation may be used instead.

References

[1]: https://arxiv.org/abs/2004.06755

Create an empty schedule.

Parameters

• *schedules – Child Schedules of this parent Schedule. May either be passed as the list of schedules, or a list of (start_time, schedule) pairs.

• name (Optional[str]) – Name of this schedule. Defaults to an autogenerated string if not provided.

• metadata (Optional[dict]) – Arbitrary key value metadata to associate with the schedule. This gets stored as free-form data in a dict in the metadata attribute. It will not be directly used in the schedule.

Raises

TypeError – if metadata is not a dict.

Methods

append	Return a new schedule with schedule inserted at the maximum time over all channels shared between self and schedule.
assign_parameters	Assign the parameters in this schedule according to the input.
ch_duration	Return the time of the end of the last instruction over the supplied channels.
ch_start_time	Return the time of the start of the first instruction over the supplied channels.
ch_stop_time	Return maximum start time over supplied channels.
draw	Plot the schedule.
exclude	Return a Schedule with only the instructions from this Schedule failing at least one of the provided filters. This method is the complement of py:meth:~self.filter, so that::.
filter	Return a new Schedule with only the instructions from this Schedule which pass though the provided filters; i.e. an instruction will be retained iff every function in filter_funcs returns True, the instruction occurs on a channel type contained in channels, the instruction type is contained in instruction_types, and the period over which the instruction operates is fully contained in one specified in time_ranges or intervals.
flatten	Deprecated.
get_parameters	Get parameter object bound to this schedule by string name.
initialize_from	Create new schedule object with metadata of another schedule object.
insert	Return a new schedule with schedule inserted into self at start_time.
is_parameterized	Return True iff the instruction is parameterized.
replace	Return a Schedule with the old instruction replaced with a new instruction.
shift	Return a schedule shifted forward by time.

Attributes

channels

Returns channels that this schedule uses.

Return type

Tuple[Channel]

children

Return the child schedule components of this Schedule in the order they were added to the schedule.

Notes

Nested schedules are returned as-is. If you want to collect only instructions, use py:meth:~Schedule.instructions instead.

Return type

Tuple[Tuple[int, Union[Schedule, Instruction]], …]

Returns

A tuple, where each element is a two-tuple containing the initial scheduled time of each NamedValue and the component itself.

duration

Duration of this schedule.

Return type

int

instances_counter = count(0)

instructions

Get the time-ordered instructions from self.

Return type

Tuple[Tuple[int, Instruction]]

metadata

The user provided metadata associated with the schedule.

User provided dict of metadata for the schedule. The metadata contents do not affect the semantics of the program but are used to influence the execution of the schedule. It is expected to be passed between all transforms of the schedule and that providers will associate any schedule metadata with the results it returns from the execution of that schedule.

Return type

Dict[str, Any]

name

Name of this Schedule

Return type

str

parameters

Parameters which determine the schedule behavior.

Return type

Set

prefix = 'sched'

start_time

Starting time of this schedule.

Return type

int

stop_time

Stopping time of this schedule.

Return type

int

timeslots

Time keeping attribute.

Return type

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