ResultsDB tutorial

[coruscating]

Summary

ResultsDB tutorial (T1 and RB) and small graphics fix in utils.py so that figures render correctly in the database without being cut off.

What's not in here/not done:

• Composite experiments: we haven't decided how to implement that in ResultsDB
• Deleting figures and/or analysis results: I tested several times and it doesn't work consistently. Deleting figures in particular doesn't seem to work at all. It's also not such an important feature that I think it's fine to leave off the tutorial for now
• T2* not in here for now because there's no figure, also doesn't really need to be in here since T1 is similar
• Tomography not in here for now because Armonk doesn't support reset
• Screenshot of ResultsDB doesn't show chi square, pending resolution of Fetch value, chisq, result_type from the result data #194

[yaelbh]

@mtreinish What's the policy about using devices in tutorials?

[yaelbh]

In your screenshot for T1, the column "Verified" is not populated. This is how it should be, but it's not the way it is right now. It's fixed in the non-merged PR #200. So I wonder how it happened.

[coruscating]

@yaelbh I fixed it temporarily just for the screenshot :p But it's not so useful since I'll have to redo the screenshot later for the chisq...

[blakejohnson]

To be clear #194 on its own won't fix chisq. It also needs to be pulled "up" a level in the dictionary. Sorry, I thought that was referencing a different issue.

[mtreinish]

@yaelbh normally using devices in tutorials is not allowed because we can't execute the tutorials in CI for PRs if they need credentials (and there is the runtime concern too if they run on a shared device). The other qiskit repos execute their tutorials in CI for PRs to validate against regressions from the PR and also before publishing the docs so the rendered pages (like https://qiskit.org/documentation/tutorials/noise/4_randomized_benchmarking.html ) are running in a consistent environment with the same versions. But so far the experiments project doesn't actually execute the tutorials in CI anywhere if you want to continue this trend then using devices is fine, but the tradeoff is that then we can't actually run tests on PRs to validate tutorials still work with code changes (and also the hosted documentation will have whatever output is set for cells in the committed version of the notebook).