ScheduleBlock

class ScheduleBlock(name=None, metadata=None, alignment_context=None)

Bases: object

A ScheduleBlock is a time-ordered sequence of instructions and transform macro to manage their relative timing. The relative position of the instructions is managed by the context_alignment. This allows ScheduleBlock to support instructions with a parametric duration and allows the lazy scheduling of instructions, i.e. allocating the instruction time just before execution.

ScheduleBlock s should be initialized with one of the following alignment contexts:

• AlignLeft: Align instructions in the as-soon-as-possible manner. Instructions are scheduled at the earliest possible time on the channel.

• AlignRight: Align instructions in the as-late-as-possible manner. Instructions are scheduled at the latest possible time on the channel.

• AlignSequential: Align instructions sequentially even though they are allocated in different channels.

• AlignEquispaced: Align instructions with equal interval within a specified duration. Instructions on different channels are aligned sequentially.

• AlignFunc: Align instructions with arbitrary position within the given duration. The position is specified by a callback function taking a pulse index j and returning a fractional coordinate in [0, 1].

The ScheduleBlock defaults to the AlignLeft alignment. The timing overlap constraint of instructions is not immediately evaluated, and thus we can assign a parameter object to the instruction duration. Instructions are implicitly scheduled at optimum time when the program is executed.

Note that ScheduleBlock can contain Instruction and other ScheduleBlock to build an experimental program, but Schedule is not supported. This should be added as a Call instruction. This conversion is automatically performed with the pulse builder.

By using ScheduleBlock representation we can fully parametrize pulse waveforms. For example, Rabi schedule generator can be defined as

duration = Parameter('rabi_dur')
amp = Parameter('rabi_amp')

block = ScheduleBlock()
rabi_pulse = pulse.Gaussian(duration=duration, amp=amp, sigma=duration/4)

block += Play(rabi_pulse, pulse.DriveChannel(0))
block += Call(measure_schedule)

Note that such waveform cannot be appended to the Schedule representation.

In the block representation, the interval between two instructions can be managed with the Delay instruction. Because the schedule block lacks an instruction start time t0, we cannot insert or shift the target instruction. In addition, stored instructions are not interchangable because the schedule block is sensitive to the relative position of instructions. Apart from these differences, the block representation can provide compatible functionality with Schedule representation.

Create an empty schedule block.

Parameters

• 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.

• alignment_context (AlignmentKind) – AlignmentKind instance that manages scheduling of instructions in this block.

Raises

TypeError – if metadata is not a dict.

Methods

append	Return a new schedule block with block appended to the context block.
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 ScheduleBlock 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.
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	This method will be removed.
is_parameterized	Return True iff the instruction is parameterized.
is_schedulable	Return True if all durations are assigned.
replace	Return a ScheduleBlock with the old component replaced with a new component.
shift	This method will be removed.

Attributes

alignment_context

Return alignment instance that allocates block component to generate schedule.

blocks

Get the time-ordered instructions from self.

Return type

Tuple[Union[ScheduleBlock, Instruction]]

channels

Returns channels that this schedule clock uses.

Return type

Tuple[Channel]

duration

Duration of this schedule block.

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 = 'block'

start_time

Starting time of this schedule block.

Return type

int

stop_time

Stopping time of this schedule block.

Return type

int

timeslots

Time keeping attribute.

Return type

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