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align_func(duration, func)

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Callback defined alignment pulse scheduling context.

Pulse instructions within this context are scheduled at the location specified by arbitrary callback function position that takes integer index and returns the associated fractional location within [0, 1]. Delay instruction is automatically inserted in between pulses.

This context may be convenient to write a schedule of arbitrary dynamical decoupling sequences such as Uhrig dynamical decoupling.


import numpy as np
from qiskit import pulse
d0 = pulse.DriveChannel(0)
x90 = pulse.Gaussian(10, 0.1, 3)
x180 = pulse.Gaussian(10, 0.2, 3)
def udd10_pos(j):
    return np.sin(np.pi*j/(2*10 + 2))**2
with as udd_sched:, d0)
    with pulse.align_func(duration=300, func=udd10_pos):
        for _ in range(10):
  , d0), d0)

(Source code, png, hires.png, pdf)



  • duration (Union[int, ParameterExpression]) – Duration of context. This should be larger than the schedule duration.
  • func (Callable[[int], float]) – A function that takes an index of sub-schedule and returns the fractional coordinate of of that sub-schedule. The returned value should be defined within [0, 1]. The pulse index starts from 1.




The scheduling is performed for sub-schedules within the context rather than channel-wise. If you want to apply the numerical context for each channel, you need to apply the context independently to channels.

Return type


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