Enabling plot circuit resolution through dpi argument

[MatteoRobbiati]

This allows to set the plot resolution.

Checklist:

• Reviewers confirm new code works as expected.
• Tests are passing.
• Coverage does not decrease.
• Documentation is updated.

[scarrazza]

@MatteoRobbiati I will remove this from the current milestone, ok?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.92%. Comparing base (473bcf7) to head (3b2d675).
Report is 71 commits behind head on master.

Additional details and impacted files

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##           master    #1435   +/-   ##
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  Coverage   99.92%   99.92%           
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  Files          81       81           
  Lines       11935    11935           
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  Hits        11926    11926           
  Misses          9        9           

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[alecandido]

Instead of adding a new separate argument, why not directly using the style one?

In principle, it accepts a dict working as an update of the PLOT_PARAMS constant above :)

[alecandido]

Otherwise, you could also add a **kwargs and merge it with the style content, in order to support also the current syntax, with no special handling for any parameter.

[MatteoRobbiati]

As it is now, the PLOT_PARAMS dictionary is collecting parameters useful in very different functions/calls of the plotter, putting together arguments of very different and sometimes also unrelated objects.

In this case, for example, the dpi argument can be passed to plt.figure, to the plt.savefig function or set directly into the plt.rcParams.

We could add it as a new argument of the PLOT_PARAMS and this is already better than adding an extra argument to the plot_circuit function indeed.

However, I feel a bit confusing to manage all these (different) tasks using the same dictionary. In particular because for now it is conceived as a tool to customize the style (looking at the example).

[alecandido]

Well, you already added dpi to PLOT_PARAMS before my comment:

qibo/src/qibo/ui/mpldrawer.py

Line 28 in 08cf82f

"dpi": 100,

In any case, there is a single task involved: plt.rcParams. Ttbomu, PLOT_PARAMS is just a subset of that, with some defaults set (and then, you have various sets of overrides to pick a certain style). Everything else is just a consequence.