https://github.com/giotto-ai/condorcet-method
This repo implements the Schulze method, a Condorcet-type election method.
https://github.com/giotto-ai/condorcet-method
Last synced: 3 months ago
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This repo implements the Schulze method, a Condorcet-type election method.
- Host: GitHub
- URL: https://github.com/giotto-ai/condorcet-method
- Owner: giotto-ai
- License: other
- Created: 2020-11-23T07:57:08.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2020-11-23T19:38:50.000Z (over 4 years ago)
- Last Synced: 2025-01-19T16:27:42.249Z (5 months ago)
- Language: Jupyter Notebook
- Size: 25.4 KB
- Stars: 3
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# condorcet-method
This repo implements the Schulze method, a Condorcet-type election method. Please refer to [Wikipedia](https://en.wikipedia.org/wiki/Schulze_method) for all the mathematical details.
## How to run the method
__1. Prepare your data__
The first step is to import your data in a dataframe. The structure has to be the following:
- Each voter has to correspond to a line
- Each row contains, ordered from the left to the right columns, the preferences of the voter
- Each entry corresponds to the name of teh candidates: make sure not to make spelling mistakes
To see a concrete example, have a look at [Run_ranking.ipynb](https://github.com/giotto-ai/condorcet-method/blob/main/Run_ranking.ipynb).
__2. Run the election method to discover the winning candidates__
To run the model once the dataframe `df` is ready, it is just one line:
```
condorcet.compute_ranks(df)
```
As in the example in the notebook, the output is a list of lists, where the position of the inner list corresponds to the ranking and if the inner lists are longer than one element, it is because there is a tie.
__3. Dive deeper__
You can extract the *d[V,W]* and *p[V,W]* matrices with the methods:
- `condorcet._compute_d(weighted_ranks, candidate_names)`
- `condorcet._compute_p(dmat, candidate_names)`
To extract the candidate names and the weighted ranks to be input to the above methods, please use:
- `weighted_ranks = condorcet.weighted_ranks_from_df(df)`
- `candidate_names = condorcet.candidate_names_from_df(df)`
## Code tests
The [Wikipedia example](https://en.wikipedia.org/wiki/Schulze_method#Example) is reproduced in the example notebook and all the entries of the *p* and *d* matrices match the original ones.
A short unit test can be run with the command `pytest` once in the repo root folder. To run the test, pytest is required. You can install it with `pip install pytest`.