Add linear programming implementation using the simplex method

[MohdFuzailHaider]

Describe your change:

• Add an algorithm?
• Fix a bug or typo in an existing algorithm?
• Add or change doctests?
• Documentation change?

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work -- I have not plagiarized.
• I know that pull requests will not be merged if they fail the automated tests.
• This PR only changes one algorithm file.
• All new Python files are placed inside an existing directory.
• All filenames are in all lowercase characters with no spaces or dashes.
• All functions and variable names follow Python naming conventions.
• All function parameters and return values are annotated with Python type hints.
• All functions have doctests that pass the automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
• If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

[MohdFuzailHaider]

Hi, it's been a few days since I submitted this pull request. I just wanted to check in to see if there is anything else needed from my end for the review process. Thank you

[CaedenPH]

@MohdFuzailHaider There is already a simplex algorithm, https://github.com/TheAlgorithms/Python/blob/master/linear_programming/simplex.py

Is this method substantially different to that of the pre-existing implementation?

[MohdFuzailHaider]

Thank you for the feedback! Upon reviewing the existing implementation in simplex.py, I believe my code offers several improvements that enhance readability, maintainability, and performance:

Modularity and Structure: My implementation uses an object-oriented approach with the Tableau class, separating concerns into distinct methods (pivot, find_pivot_column, find_pivot_row, etc.). This makes the code easier to follow, debug, and maintain.

Efficiency: I’ve used NumPy for efficient matrix operations, which provides a performance advantage for larger problems. The pivoting operation, for instance, is handled in a vectorized manner, improving execution speed compared to basic Python loops.

Extensibility: The modular design of my code allows for easier future extensions. For example, introducing different pivoting rules or handling degeneracy would require minimal changes.

Error Handling: My code explicitly raises an error when the linear program is unbounded, improving robustness and making debugging simpler.

Solution Extraction: The extract_solution method clearly identifies basic variables, ensuring that the solution is correctly extracted from the tableau.

I believe these enhancements could be beneficial, particularly for larger or more complex linear programming problems.