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class qiskit.pulse.Schedule(*schedules, name=None, metadata=None)

GitHub(opens in a new tab)

Bases: object(opens in a new tab)

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.


[1]: in a new tab)

Create an empty schedule.


  • *schedules (ScheduleComponent | Tuple(opens in a new tab)[int(opens in a new tab), ScheduleComponent]) – Child Schedules of this parent Schedule. May either be passed as the list of schedules, or a list of (start_time, schedule) pairs.
  • name (str(opens in a new tab) | None) – Name of this schedule. Defaults to an autogenerated string if not provided.
  • metadata (dict(opens in a new tab) | None) – 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.


TypeError(opens in a new tab) – if metadata is not a dict.



Returns channels that this schedule uses.


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


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


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


Duration of this schedule.


Default value: count(0)


Get the time-ordered instructions from self.


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.


Name of this Schedule


Parameters which determine the schedule behavior.


Default value: 'sched'


Starting time of this schedule.


Stopping time of this schedule.


Time keeping attribute.



append(schedule, name=None, inplace=False)

Return a new schedule with schedule inserted at the maximum time over all channels shared between self and schedule.

t=max(x.stop_timexself.channelsschedule.channels)t = \textrm{max}(\texttt{x.stop\_time} |\texttt{x} \in \texttt{self.channels} \cap \texttt{schedule.channels})


Return type



assign_parameters(value_dict, inplace=True)

Assign the parameters in this schedule according to the input.



Schedule with updated parameters.

Return type




Return the time of the end of the last instruction over the supplied channels.


*channels (Channel) – Channels within self to include.

Return type

int(opens in a new tab)



Return the time of the start of the first instruction over the supplied channels.


*channels (Channel) – Channels within self to include.

Return type

int(opens in a new tab)



Return maximum start time over supplied channels.


*channels (Channel) – Channels within self to include.

Return type

int(opens in a new tab)


draw(style=None, backend=None, time_range=None, time_unit='dt', disable_channels=None, show_snapshot=True, show_framechange=True, show_waveform_info=True, show_barrier=True, plotter='mpl2d', axis=None)

Plot the schedule.


  • style (Dict(opens in a new tab)[str(opens in a new tab), Any(opens in a new tab)] | None) – Stylesheet options. This can be dictionary or preset stylesheet classes. See IQXStandard, IQXSimple, and IQXDebugging for details of preset stylesheets.

  • backend (Optional[BaseBackend]) – Backend object to play the input pulse program. If provided, the plotter may use to make the visualization hardware aware.

  • time_range (Tuple(opens in a new tab)[int(opens in a new tab), int(opens in a new tab)] | None) – Set horizontal axis limit. Tuple (tmin, tmax).

  • time_unit (str(opens in a new tab)) – The unit of specified time range either dt or ns. The unit of ns is available only when backend object is provided.

  • disable_channels (List(opens in a new tab)[Channel] | None) – A control property to show specific pulse channel. Pulse channel instances provided as a list are not shown in the output image.

  • show_snapshot (bool(opens in a new tab)) – Show snapshot instructions.

  • show_framechange (bool(opens in a new tab)) – Show frame change instructions. The frame change represents instructions that modulate phase or frequency of pulse channels.

  • show_waveform_info (bool(opens in a new tab)) – Show additional information about waveforms such as their name.

  • show_barrier (bool(opens in a new tab)) – Show barrier lines.

  • plotter (str(opens in a new tab)) –

    Name of plotter API to generate an output image. One of following APIs should be specified:

    mpl2d: Matplotlib API for 2D image generation.
        Matplotlib API to generate 2D image. Charts are placed along y axis with
        vertical offset. This API takes matplotlib.axes.Axes as ``axis`` input.

    axis and style kwargs may depend on the plotter.

  • axis (Any(opens in a new tab) | None) – Arbitrary object passed to the plotter. If this object is provided, the plotters use a given axis instead of internally initializing a figure object. This object format depends on the plotter. See plotter argument for details.


Visualization output data. The returned data type depends on the plotter. If matplotlib family is specified, this will be a matplotlib.pyplot.Figure data.


exclude(*filter_funcs, channels=None, instruction_types=None, time_ranges=None, intervals=None, check_subroutine=True)

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:

self.filter(args) | self.exclude(args) == self


Return type



filter(*filter_funcs, channels=None, instruction_types=None, time_ranges=None, intervals=None, check_subroutine=True)

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.

If no arguments are provided, self is returned.


Return type




Get parameter object bound to this schedule by string name.

Because different Parameter objects can have the same name, this method returns a list of Parameter s for the provided name.


parameter_name (str(opens in a new tab)) – Name of parameter.


Parameter objects that have corresponding name.

Return type

List(opens in a new tab)[Parameter]


classmethod initialize_from(other_program, name=None)

Create new schedule object with metadata of another schedule object.



New schedule object with name and metadata.


PulseError – When other_program does not provide necessary information.

Return type



insert(start_time, schedule, name=None, inplace=False)

Return a new schedule with schedule inserted into self at start_time.


Return type




Return True iff the instruction is parameterized.

Return type

bool(opens in a new tab)


replace(old, new, inplace=False)

Return a Schedule with the old instruction replaced with a new instruction.

The replacement matching is based on an instruction equality check.

from qiskit import pulse
d0 = pulse.DriveChannel(0)
sched = pulse.Schedule()
old = pulse.Play(pulse.Constant(100, 1.0), d0)
new = pulse.Play(pulse.Constant(100, 0.1), d0)
sched += old
sched = sched.replace(old, new)
assert sched == pulse.Schedule(new)

Only matches at the top-level of the schedule tree. If you wish to perform this replacement over all instructions in the schedule tree. Flatten the schedule prior to running:

.. code-block::

sched = pulse.Schedule()

sched += pulse.Schedule(old)

sched = sched.flatten()

sched = sched.replace(old, new)

assert sched == pulse.Schedule(new)



The modified schedule with old replaced by new.


PulseError – If the Schedule after replacements will has a timing overlap.

Return type



shift(time, name=None, inplace=False)

Return a schedule shifted forward by time.


Return type


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