Combined Parameters

import numpy as np
import qcodes as qc
from qcodes.parameters import ManualParameter, combine
from qcodes.validators import Numbers

from qcodes_loop.loops import Loop

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If you want to sweep multiple parameters at once qcodes offers the combine function. You can combine any number of any kind paramter. We’ll use a ManualParameter for this example.

p1 = ManualParameter('p1', vals=Numbers(-10, 10))
p2 = ManualParameter('p2', vals=Numbers(-10, 10))
p3 = ManualParameter('p3', vals=Numbers(-10, 10))
p4 = ManualParameter('p4', vals=Numbers(-10, 10))
# set to -1 so we get some data out
p4.set(-1)

Simple combined parameters

combined = combine(p1, p2, p3, name='combined')

sweep_vals = np.array([[1, 1,1], [1, 1,1]])

# 2d loop with a inner loop over a combined parameter
loop = Loop(p1.sweep(0,10,1)).loop(combined.sweep(sweep_vals), delay=0.001).each(p4)

data = loop.get_data_set(name='testsweep')

data = loop.run()

Started at 2020-03-24 18:35:07
DataSet:
   location = 'data/2020-03-24/#004_testsweep_18-35-07'
   <Type>   | <array_id>   | <array.name> | <array.shape>
   Setpoint | p1_set       | p1           | (11,)
   Setpoint | combined_set | combined     | (11, 2)
   Measured | p4           | p4           | (11, 2)
   Measured | p1           | p1           | (11, 2)
   Measured | p2           | p2           | (11, 2)
   Measured | p3           | p3           | (11, 2)
Finished at 2020-03-24 18:35:07

The combined_set just stores the indices

print(data.combined_set)

DataArray[11,2]: combined_set
array([[0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.],
       [0., 1.]])

But the acutal set values are saved, but labeled as “measured”

data.p3

DataArray[11,2]: p3
array([[1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.],
       [1., 1.]])

Combine and aggregate parameters

If an aggregator function is given, the aggregated values are saved instead of the indices.

# define an aggregator function that takes as arguments the parameters you whish to aggegate
def linear(x,y,z):
    return x+y+z

combined = combine(p1, p2, p3, name='combined', label="Sum", unit="a.u", aggregator=linear)

x_vals = np.linspace(1, 2, 2)
y_vals = np.linspace(1, 2, 2)
z_vals = np.linspace(1, 2, 2)

# 2d loop with a inner loop over a combined parameter
loop = Loop(p1.sweep(0,10,1)).loop(combined.sweep(x_vals, y_vals, z_vals), delay=0.001).each(p4)

data = loop.get_data_set(name='testsweep')

data = loop.run()

Started at 2020-03-24 18:35:07
DataSet:
   location = 'data/2020-03-24/#005_testsweep_18-35-07'
   <Type>   | <array_id>   | <array.name> | <array.shape>
   Setpoint | p1_set       | p1           | (11,)
   Setpoint | combined_set | combined     | (11, 2)
   Measured | p4           | p4           | (11, 2)
   Measured | p1           | p1           | (11, 2)
   Measured | p2           | p2           | (11, 2)
   Measured | p3           | p3           | (11, 2)
Finished at 2020-03-24 18:35:07

the combined_set now stores the aggregated values

print(data.combined_set)

DataArray[11,2]: combined_set
array([[3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.],
       [3., 6.]])

# snapshot of the combined parameter
combined.snapshot()

OrderedDict([('__class__', 'qcodes.instrument.parameter.CombinedParameter'),
             ('unit', 'a.u'),
             ('label', 'Sum'),
             ('full_name', 'combined'),
             ('aggregator', '<function linear at 0x0000024683100828>'),
             ('p1',
              {'value': 2.0,
               'raw_value': 2.0,
               'ts': '2020-03-24 18:35:07',
               '__class__': 'qcodes.instrument.parameter.ManualParameter',
               'full_name': 'p1',
               'post_delay': 0,
               'label': 'p1',
               'inter_delay': 0,
               'vals': '<Numbers -10<=v<=10>',
               'unit': '',
               'name': 'p1'}),
             ('p2',
              {'value': 2.0,
               'raw_value': 2.0,
               'ts': '2020-03-24 18:35:07',
               '__class__': 'qcodes.instrument.parameter.ManualParameter',
               'full_name': 'p2',
               'post_delay': 0,
               'label': 'p2',
               'inter_delay': 0,
               'vals': '<Numbers -10<=v<=10>',
               'unit': '',
               'name': 'p2'}),
             ('p3',
              {'value': 2.0,
               'raw_value': 2.0,
               'ts': '2020-03-24 18:35:07',
               '__class__': 'qcodes.instrument.parameter.ManualParameter',
               'full_name': 'p3',
               'post_delay': 0,
               'label': 'p3',
               'inter_delay': 0,
               'vals': '<Numbers -10<=v<=10>',
               'unit': '',
               'name': 'p3'})])