Adding new feature wire_options to draw_mpl function

[zazabap]

Context:
On the level of mid-scale algorithms, it might be nice to differentiate between different "types" of wires, for example by coloring them differently, or giving them distinct line styles. As an example, in PennyLaneAI/qml#1185 on preparing matrix product states, there are auxiliary bond qubits and physical qubits, and coloring them differently would be a neat thing to do.

Description of the Change:
Update the output wire_options that could change the line style and color for circuit output.

        @qml.qnode(qml.device("default.qubit"))
        def node(x):
            for w in range(5):
                qml.Hadamard(w) 
            return qml.expval(qml.PauliZ(0) @ qml.PauliY(1))

        # Make all wires cyan and bold, 
        # except for wires 2 and 6, which are dashed and another color
        wire_options = {"color": "cyan", 
                        "linewidth": 5, 
                        2: {"linestyle": "--", "color": "red"}, 
                        6: {"linestyle": "--", "color": "orange"}
                    }
        _,ax  = qml.draw_mpl(node, wire_options=wire_options)(0.52)

Benefits:
When complicated sates and quantum circuits diagram are created, wires could be marked with different selections.

Possible Drawbacks:
N/A

Related GitHub Issues:
#6165

[zazabap]

Dear @dwierichs, I made necessary changes here for the test cases, documentation, and source code. However, I am not so familiar with the format check here. Sorry maybe I need some additional help on it.

[dwierichs]

Hi @zazabap,
Great, thank you for your contribution. Is it ready to be reviewed? :)
Regarding the continuous integration checks, including formatting checks, take a look at our guide on how to submit a PR.
In particular, you want to pip install -r requirements-dev.txt while in the PennyLane directory and then run
black -l 100 pennylane tests. Other formatting tests likely will not be super relevant in this PR (unless pylint complains, but this we can handle once we get there :) )
Hope this helps! Let me know when we can move to review!

[zazabap]

Thanks a lot for the help! I have reformatted the modified files and commit again, I think now it is ready for review. I resolved all the format check and unit test today @dwierichs .

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.34%. Comparing base (403c7a3) to head (39e1369).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #6486   +/-   ##
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  Coverage   99.34%   99.34%           
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  Files         455      455           
  Lines       43193    43232   +39     
=======================================
+ Hits        42909    42948   +39     
  Misses        284      284           

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[dwierichs]

Amazing addition @zazabap !
Looking forward to getting this feature in! 💯
I had some comments, in particular the documentation update should be moved to the docstrings of the respective functions, and the criterion with which we determine whether something is a per-wire option needs to be modified.

Thanks again, and let me know any questions you might have!

[zazabap]

Dear @dwierichs , I think now everything is updated and ready to merge. Please let me know if there are further questions or requests.

[dwierichs]

@zazabap Thanks for the stamina with this contribution! 🎉
I will request a second review internally and then we can go ahead and merge :)

[astralcai]

Some minor comments

[dwierichs]

Hi @zazabap
We're experiencing problems with CI across the board. I think this PR is essentially merge-ready, so we'll merge it in as soon as we technically can :)
Thank you for this nice contribution! 🎉

[astralcai]

Thank you for your contribution!