Add Calibration logging for PEC

[Misty-W]

Description

Add Calibration logging for PEC.

Fixes #1861

A mixture of ZNE and PEC strategies is also supported in a simple way, as the appropriate header is printed initially and when the current technique is different from the previous technique.

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License

• I license this contribution under the terms of the GNU GPL, version 3 and grant Unitary Fund the right to provide additional permissions as described in section 7 of the GNU GPL, version 3.

Before opening the PR, please ensure you have completed the following where appropriate.

• I added unit tests for new code.
• I used type hints in function signatures.
• I used Google-style docstrings for functions.
• I updated the documentation where relevant.
• Added myself / the copyright holder to the AUTHORS file

[github-actions]

👈 Launch a binder notebook on branch unitaryfund/mitiq/1861-logs-for-pec-calibration

[codecov]

Codecov Report

Merging #1873 (c15ba4e) into master (6761302) will increase coverage by 98.53%.
Report is 3 commits behind head on master.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##           master    #1873       +/-   ##
===========================================
+ Coverage        0   98.53%   +98.53%     
===========================================
  Files           0       79       +79     
  Lines           0     3694     +3694     
===========================================
+ Hits            0     3640     +3640     
- Misses          0       54       +54     

Files Changed	Coverage Δ
mitiq/calibration/calibrator.py	98.18% <100.00%> (ø)
mitiq/calibration/settings.py	99.43% <100.00%> (ø)

... and 77 files with indirect coverage changes

[Misty-W]

@natestemen, thought I'd clarify that this PR is ready for review now (after a few false starts, oops!)

[natestemen]

Nice work, and good tests. Biggest request is getting the lines to print in a formatted way similar to ZNE, but most other stuff looks good.

[natestemen]

When running an example using the light_pec_settings from the tests it's printing out double headers.

The function name is also overflowing it's column. Do you think continuing to use a table here is the right choice if you want to print out the operations? I don't see a way that will fit in a text table.

[Misty-W]

When running an example using the light_pec_settings from the tests it's printing out double headers.

Thanks for pointing this out @natestemen! Not sure how I missed this behavior before, but it turned out that the count determining whether to print the header "initially" was resetting with every "problem" instance.

[Misty-W]

The function name is also overflowing it's column. Do you think continuing to use a table here is the right choice if you want to print out the operations? I don't see a way that will fit in a text table.

I propose to keep the table and remove the operations, since all 2-qubit op's are represented by default now when running PEC calibration. Working on this change plus some other improvements now.

[natestemen]

Nice work Misty! Thanks for working to ensure everything fits into the table nicely.