qiskit.pulse.transforms.block_to_dag

block_to_dag(block)

Convert schedule block instruction into DAG.

ScheduleBlock can be represented as a DAG as needed. For example, equality of two programs are efficiently checked on DAG representation.

with pulse.build() as sched1:
    with pulse.align_left():
        pulse.play(my_gaussian0, pulse.DriveChannel(0))
        pulse.shift_phase(1.57, pulse.DriveChannel(2))
        pulse.play(my_gaussian1, pulse.DriveChannel(1))
 
with pulse.build() as sched2:
    with pulse.align_left():
        pulse.shift_phase(1.57, pulse.DriveChannel(2))
        pulse.play(my_gaussian1, pulse.DriveChannel(1))
        pulse.play(my_gaussian0, pulse.DriveChannel(0))

Here the sched1 `` and ``sched2 are different implementations of the same program, but it is difficult to confirm on the list representation.

Another example is instruction optimization.

with pulse.build() as sched:
    with pulse.align_left():
        pulse.shift_phase(1.57, pulse.DriveChannel(1))
        pulse.play(my_gaussian0, pulse.DriveChannel(0))
        pulse.shift_phase(-1.57, pulse.DriveChannel(1))

In above program two shift_phase instructions can be cancelled out because they are consecutive on the same drive channel. This can be easily found on the DAG representation.

Parameters

block (ScheduleBlock) – A schedule block to be converted.

Return type

PyDAG

Returns

Instructions in DAG representation.

Raises

PulseError – When the context is invalid subclass.