def moment_by_moment_schedule(device: Device, circuit: Circuit):
"""Returns a schedule aligned with the moment structure of the Circuit.
This method attempts to create a schedule in which each moment of a circuit
is scheduled starting at the same time. Given the constraints of the
given device, such a schedule may not be possible, in this case the
the method will raise a ValueError with a description of the conflict.
The schedule that is produced will take each moments and schedule the
operations in this moment in a time slice of length equal to the maximum
time of an operation in the moment.
Returns:
A Schedule for the circuit.
Raises:
ValueError: if the scheduling cannot be done.
"""
schedule = Schedule(device)
t = Timestamp()
for moment in circuit.moments:
if not moment.operations:
continue
for op in moment.operations:
scheduled_op = ScheduledOperation.op_at_on(op, t, device)
# Raises a ValueError describing the problem if this cannot be
# scheduled.
schedule.include(scheduled_operation=scheduled_op)
# Raises ValueError at first sign of a device conflict.
device.validate_scheduled_operation(schedule, scheduled_op)
# Increment time for next moment by max of ops during this moment.
max_duration = max(device.duration_of(op) for op in moment.operations)
t += max_duration
return schedule
def test_include():
q0 = ops.QubitId()
q1 = ops.QubitId()
zero = Timestamp(picos=0)
ps = Duration(picos=1)
schedule = Schedule(device=UnconstrainedDevice)
op0 = ScheduledOperation(zero, ps, ops.H(q0))
schedule.include(op0)
with pytest.raises(ValueError):
schedule.include(ScheduledOperation(zero, ps, ops.H(q0)))
schedule.include(ScheduledOperation(zero + 0.5 * ps, ps, ops.H(q0)))
op1 = ScheduledOperation(zero + 2 * ps, ps, ops.H(q0))
schedule.include(op1)
op2 = ScheduledOperation(zero + 0.5 * ps, ps, ops.H(q1))
schedule.include(op2)
assert schedule.query(time=zero, duration=ps * 10) == [op0, op2, op1]