gsimplex 0.0.4

Implementation of simplex algorithm controlled by the primal-dual gap

Gap controlled Simplex

gsimplex is a lightweight Python package that implements a simplex solver governed by the primal-dual gap. It integrates directly with pulp and uses numpy for its linear algebra routines. The current release supports continuous linear programming problems; mixed-integer support may be added in a future version.

Features

• pulp compatible solver backend
• Gap-controlled primal/dual simplex algorithms
• Easy installation from PyPI or source
• Built-in benchmark downloader for Plato and Netlib test sets

Installation

Install from PyPI:

python -m pip install gsimplex

Install from source for local development:

git clone https://github.com/Richie314/GapControlledSimplex.git
cd GapControlledSimplex
python -m pip install -e .
python -m pip install -e .[dev]

Run the test suite with:

python -m pytest

Usage

from pulp import LpVariable, LpProblem, LpMaximize
from gsimplex.solvers import PrimalSimplex

x1 = LpVariable("x1", lowBound=0, upBound=1)
x2 = LpVariable("x2", lowBound=0, upBound=3)

problem = LpProblem("Problem", LpMaximize)
problem += x1 + x2
problem += x1 + x2 <= 2
problem += x1 <= 1
problem += x2 <= 3
problem += x1 >= 0
problem += x2 >= 0

solver = PrimalSimplex()
problem.solve(solver)

print("Optimal value:", problem.objective.value()) # 2.0
print("Solution:", [var.varValue for var in problem.variables()]) # [1.0, 1.0]

Download benchmark problems

This package installs a command-line helper called gsimplex-download-benchmarks. It downloads the Plato and Netlib benchmark sets into a local directory, so you can test the solver on real LP problems.

By default, benchmark files are saved under the benchmark/ directory in the current working directory. Plato files are stored in benchmark/plato/, and Netlib files are stored in benchmark/netlib/.

Download all benchmarks

gsimplex-download-benchmarks

Download only one benchmark set

gsimplex-download-benchmarks --plato True --netlib False
# or
gsimplex-download-benchmarks --plato False --netlib True

Note: the CLI uses boolean flags for --plato and --netlib, so set the one you want to disable to False.

Change the destination directory

gsimplex-download-benchmarks --dir benchmark

Quiet mode

gsimplex-download-benchmarks --quiet

If you installed the package editable with pip install -e ., the command will be available immediately.