Measurement of array like values

[AdriaanRol]

Feature as discussed in V0.1 QCodes meeting

parameter.setpoints = np.linspace() 
dataset = Measure(parameter)

[nataliejpg]

links to #243 as we can currently measure but only as part of a loop. I'll close that issue

[giulioungaretti]

@AdriaanRol @nataliejpg .
For the sake of clarity, #243 and this are two different things right ?

[alexcjohnson]

In #274 there was a question whether we need separate setup and teardown actions also for Measure. I don't think so - you can just include your before and after actions in the same list, and if they don't generate any data we won't record any data from them, just like Loop().each(...):

qc.Measure(Task(get_ready),
           vna.s11, vna.s21,
           Task(change_something),
           vna.s11, vna.s21,
           Task(close_up))

re: Measure().run() - it would be nice to be able to keep a pre-defined measurement around and reuse it, like you can with Loops (and also use the measurement inside a Loop!). Also it helps partition the arguments between actions/parameters and the settings to execute them and save the results. However Measure().run() is not grammatically correct... perhaps Measurement().run()? Then we would always be free to implement a quicker convenience function like:

def measure(*args, **kwargs):
    return Measurement(*args).run(**kwargs)

for when you don't care about saving the measurement for later.

[nataliejpg]

@giulioungaretti I think that this was part of #243 (in fact I think it's the first bullet point in alexcjohnson's comment on that issue). That issue was about having an arraylike harware measured parameter. That is now implemented however you can only do '2d' measurement in a Loop because it is currently not possible to create a dataset from a single parameter measurement which this issue addresses. I linked it because I would say that the functionality of an arraylike parameter is not complete if you can't do a 'single shot' measurement of it.

[spauka]

@alexcjohnson Regarding #274 and having first and then actions, I view the concept of loops and measurement to be closely related and so it makes sense to try and keep the functionality of Measurement and Loop as similar as possible. There are situations where I want to test the first point of a long running loop, which can be done using a Measurement so I propose having as much syntax overlap as possible between the two actions.

In addition to that, conceptually I view actions that happen as part of setting up and tearing down not to be part of the measurement action, so there is an argument for separating it out of the body of the measurement for that reason as well.

The new name you propose for Measurement you propose makes a lot of sense, I agree that that is clearer.

[nataliejpg]

Is this something which is hard to implement @giulioungaretti @alexcjohnson ? I don't have a good enough understanding of how the DataServer and DataSet work but since it is now possible to manually create a DataSet it superficially seems to me that this isn't much harder? Is anyone doing this sort of measurement currently by manually creating a DataSet? @peendebak I think you mentioned this?