Floating-point Coordinate type

[N-Wouda]

This PR:

• Closes Allow different value types for different measures #907.
• Adds and passes relevant tests.
• Has well-formatted code and documentation.

TODO:

• Clean up
• Retype std::pair<double, double> centroid to std::pair<Coordinate, Coordinate>

Details

Notes:

Please read our contributing guidelines first.
In particular:

• You must add tests when making code changes.
  This keeps the code coverage level up, and helps ensure the changes work as intended.
• When fixing a bug, you must add a test that would produce the bug in the master branch, and then show that it is fixed with the new code.
• New code additions must be well formatted. Changes should pass the pre-commit workflow, which you can set up locally using pre-commit.
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• Finally, it is essential that all contributions in this PR are license-compatible with PyVRP's MIT license.
  Please check that this PR can be included into PyVRP under the MIT license.

[N-Wouda]

Fairly wonky stub for this idea. Needs more work but seems to be functional already.

[codecov]

Codecov Report

❌ Patch coverage is 91.66667% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 96.19%. Comparing base (022e18b) to head (b14babc).
⚠️ Report is 35 commits behind head on main.

Files with missing lines	Patch %	Lines
pyvrp/cpp/Measure.h	84.61%	0 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #908      +/-   ##
==========================================
+ Coverage   96.17%   96.19%   +0.02%     
==========================================
  Files          79       79              
  Lines        4625     4629       +4     
  Branches     1469     1477       +8     
==========================================
+ Hits         4448     4453       +5     
  Misses         27       27              
+ Partials      150      149       -1     

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[codspeed-hq]

CodSpeed Performance Report

Merging #908 will not alter performance

_{Comparing floating-point-coords (b14babc) with main (022e18b)}

Summary

✅ 45 untouched

[N-Wouda]

I think this was a subtle bug, because size() can be zero for empty routes.

[N-Wouda]

Haha, yeah, this was bugged:

[leonlan]

LGTM. Just one thing in the quick tutorial that we should update:

PyVRP automatically converts all numeric input values to integers. If your data has decimal values, you must scale and convert them to integers first to avoid unexpected behaviour.

I don't think we'll make any of the other parameters float anytime soon, so we can just change it like this:

PyVRP automatically converts all numeric inputs to integers, except for client x and y coordinates. If your data has decimal values, you must scale and convert them to integers first to avoid unexpected behaviour.

[N-Wouda]

Forgot about the tutorial, thanks!