Fix winner distribution plots: center on voter median (#22)

[endolith]

Summary

• tomlinson_2023_figure_3_updated.py: Winner positions minus voter median per election; ideal = candidate nearest that median (issue Remove discrepancy from winner distribution plots #22).
• tomlinson_2023_figure_3.py: Same anchoring idea for the Figure 3 reproduction: one voter-sample median ref translates both uniform draws on ([0,1]) so distances are unchanged but the realized median sits at 0.5 (consistent with the updated script).
• distributions_by_*: Unchanged from master (no issue Remove discrepancy from winner distribution plots #22 centering there).

Closes #22.

Testing

• python3 -m pytest tests/ -q (191 passed)

  

[what-the-diff]

PR Summary

• Introduction of Reference Calculation for Winner Positions
  This update introduces a new calculation for determining the winner positions in relation to the electorate center. This improvement provides a more accurate representation of the winner position.

• Enhanced Accuracy in Appending Winners to Lists
  The approach for adding winners to the lists has been updated. This change makes it more precise and accurate by taking into consideration the reference points from candidate positions across various voting methods.

• Modification in the Ideal Winner Method
  The description and logic of the ideal winner method have been altered. Now, it refers to the nearest voter median instead of the center, which helps in providing a more exact and realistic representation of the winner.

• Improved Explanation via Comments
  The comments in the code have been updated to better explain that the winner positions are visualized in relation to the electorate center. These revisions provide a clearer background for the modifications implemented.

• Consistency in Formatting and Naming
  There have been improvements in the formatting and naming related to reference calculations, ensuring a more readable and understandable code by enforcing consistency across all modified files.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.31%. Comparing base (8a7213f) to head (438e16c).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #45   +/-   ##
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  Coverage   96.31%   96.31%           
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  Files          19       19           
  Lines         489      489           
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  Hits          471      471           
  Misses         18       18           

Flag	Coverage Δ
no-numba	95.50% <ø> (ø)
numba	89.16% <ø> (ø)

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