Measure without a Loop

If you have a parameter that returns a whole array at once, often you want to measure it directly into a DataSet.

This shows how that works in QCoDeS

%matplotlib nbagg
import numpy as np

# import dummy driver for the tutorial
from qcodes.instrument_drivers.mock_instruments import (
    DummyChannelInstrument,
    DummyInstrument,
)
from qcodes.station import Station

from qcodes_loop.actions import Task
from qcodes_loop.measure import Measure

dac1 = DummyInstrument(name="dac")
dac2 = DummyChannelInstrument(name="dac2")


# the default dummy instrument returns always a constant value, in the following line we make it random
# just for the looks 💅
dac2.A.dummy_array_parameter.get =  lambda: np.random.randint(0, 100, size=5)

# The station is a container for all instruments that makes it easy
# to log meta-data
station = Station(dac1, dac2)

2020-03-24 18:45:32,769 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanA(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis
2020-03-24 18:45:32,798 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanB(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis
2020-03-24 18:45:32,804 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanC(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis
2020-03-24 18:45:32,807 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanD(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis
2020-03-24 18:45:32,819 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanE(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis
2020-03-24 18:45:32,838 ¦ qcodes.instrument.base ¦ WARNING ¦ base ¦ snapshot_base ¦ 214 ¦ [dac2_ChanF(DummyChannel)] Snapshot: Could not update parameter: dummy_sp_axis

Instantiates all the instruments needed for the demo

For this tutorial we’re going to use the regular parameters (c0, c1, c2, vsd) and ArrayGetter, which is just a way to construct a parameter that returns a whole array at once out of simple parameters, as well as AverageAndRaw, which returns a scalar and an array together.

Only array output

The arguments to Measure are all the same actions you use in a Loop. If they return only arrays, you will see exactly those arrays (with their setpoints) in the output DataSet

data = Measure(
    Task(dac1.dac1.set, 0),
    dac2.A.dummy_array_parameter,
    Task(dac1.dac1.set, 2),
    dac2.A.dummy_array_parameter,
).run()

DataSet:
   location = 'data/2020-03-24/#013_{name}_18-45-41'
   <Type>   | <array_id>                         | <array.name>          | <array.shape>
   Measured | dac2_ChanA_dummy_array_parameter_1 | dummy_array_parameter | (5,)
   Measured | dac2_ChanA_dummy_array_parameter_3 | dummy_array_parameter | (5,)
acquired at 2020-03-24 18:45:41