Thanks to visit codestin.com
Credit goes to github.com

Skip to content

Optimization solvers in pure Python: LP, MILP, SAT, constraint programming, and metaheuristics. No dependencies. Local tool brought to github and modernized. 1.0 Release will use Rust for performance critical operations.

License

Notifications You must be signed in to change notification settings

StevenBtw/solvOR

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

43 Commits
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Repository files navigation

solvOR

Python 3.13+ License: Apache-2.0

Solvor your optimization needs..

What's in the box?

Category Solvors Use Case
Linear/Integer solve_lp, solve_milp Resource allocation, scheduling
Constraint solve_sat Sudoku, configuration, puzzles
Local Search anneal, tabu_search TSP, combinatorial optimization
Population evolve When you want nature to do the work
Continuous gradient_descent, momentum, adam ML, curve fitting
Black-box bayesian_opt Hyperparameter tuning, expensive functions
Graph max_flow, min_cost_flow, solve_assignment Matching, transportation
Exact Cover solve_exact_cover Sudoku, N-Queens, tiling puzzles

Quickstart

uv add solvor
from solvor import solve_lp, solve_tsp, anneal, Model

# Linear Programming
result = solve_lp(c=[1, 2], A=[[1, 1], [2, 1]], b=[4, 5])
print(result.solution)  # optimal x

# TSP with tabu search
distances = [[0, 10, 15], [10, 0, 20], [15, 20, 0]]
result = solve_tsp(distances)
print(result.solution)  # best tour found

# Constraint satisfaction
m = Model()
x = m.int_var(1, 9, 'x')
y = m.int_var(1, 9, 'y')
m.add(m.all_different([x, y]))
m.add(m.sum_eq([x, y], 10))
result = m.solve()
print(result.solution)  # {'x': 3, 'y': 7}

Solvors

Linear & Integer Programming

solve_lp

For resource allocation, blending, production planning. Finds the exact optimum for linear objectives with linear constraints.

# minimize 2x + 3y subject to x + y >= 4, x <= 3
result = solve_lp(
    c=[2, 3],
    A=[[-1, -1], [1, 0]],  # constraints as Ax <= b
    b=[-4, 3]
)

solve_milp

When some variables must be integers. Diet problems, scheduling with discrete slots, set covering.

# same as above, but x must be integer
result = solve_milp(c=[2, 3], A=[[-1, -1], [1, 0]], b=[-4, 3], integers=[0])
Constraint Programming

solve_sat

For "is this configuration valid?" problems. Dependencies, exclusions, implications - anything that boils down to boolean constraints.

# (x1 OR x2) AND (NOT x1 OR x3) AND (NOT x2 OR NOT x3)
result = solve_sat([[1, 2], [-1, 3], [-2, -3]])
print(result.solution)  # {1: True, 2: False, 3: True}

Model (CP-SAT)

For puzzles and scheduling with "all different", arithmetic, and logical constraints. Sudoku, N-Queens, timetabling.

m = Model()
cells = [[m.int_var(1, 9, f'c{i}{j}') for j in range(9)] for i in range(9)]

# All different in each row
for row in cells:
    m.add(m.all_different(row))

result = m.solve()
Metaheuristics

anneal

Simulated annealing, accepts worse solutions probabilistically.

result = anneal(
    initial=initial_solution,
    objective_fn=cost_function,
    neighbors=random_neighbor,
    temperature=1000,
    cooling=0.9995
)

tabu_search

Greedy local search with memory. Prevents cycling back to recent solutions, forcing exploration of new territory. More deterministic than anneal.

result = tabu_search(
    initial=initial_solution,
    objective_fn=cost_function,
    neighbors=get_neighbors,  # returns [(move, solution), ...]
    cooldown=10
)

evolve

Population-based search. More overhead than anneal/tabu, but better diversity and parallelizable.

result = evolve(
    objective_fn=fitness,
    population=initial_pop,
    crossover=my_crossover,
    mutate=my_mutate,
    max_gen=100
)
Continuous Optimization

gradient_descent / momentum / adam

Follow the slope downhill. Great for polishing solutions from other methods if your objective is differentiable. Adam adapts learning rates per parameter - usually the default choice.

def grad_fn(x):
    return [2 * x[0], 2 * x[1]]  # gradient of x^2 + y^2

result = adam(grad_fn, x0=[5.0, 5.0])
print(result.solution)  # [~0, ~0]

bayesian_opt

When each evaluation is expensive (think hyperparameter tuning, simulations). Builds a surrogate model to guess where to sample next instead of brute-forcing.

def expensive_fn(x):
    # imagine this takes 10 minutes to evaluate
    return (x[0] - 0.3)**2 + (x[1] - 0.7)**2

result = bayesian_opt(expensive_fn, bounds=[(0, 1), (0, 1)], max_iter=30)
Network Flow

max_flow

"How much can I push through this network?" Assigning workers to tasks, finding bottlenecks. The max-flow min-cut theorem gives you bottleneck analysis for free.

graph = {
    's': [('a', 10, 0), ('b', 5, 0)],
    'a': [('b', 15, 0), ('t', 10, 0)],
    'b': [('t', 10, 0)],
    't': []
}
result = max_flow(graph, 's', 't')
print(result.objective)  # total flow
print(result.solution)   # edge flows dict

min_cost_flow / solve_assignment

"What's the cheapest way to route X units?" Transportation, logistics, matching with costs.

# Assignment problem: 3 workers, 3 tasks
costs = [
    [10, 5, 13],
    [3, 9, 18],
    [10, 6, 12]
]
result = solve_assignment(costs)
# result.solution[i] = task assigned to worker i
# result.objective = total cost
Exact Cover

solve_exact_cover

For "place these pieces without overlap" or "fill this grid with exactly one of each" problems. Sudoku, pentomino tiling, scheduling where every slot must be filled exactly once.

# Tiling problem: cover all columns with non-overlapping rows
matrix = [
    [1, 1, 0, 0],  # row 0 covers columns 0, 1
    [0, 1, 1, 0],  # row 1 covers columns 1, 2
    [0, 0, 1, 1],  # row 2 covers columns 2, 3
    [1, 0, 0, 1],  # row 3 covers columns 0, 3
]
result = solve_exact_cover(matrix)
# result.solution = (0, 2) or (1, 3) - rows that cover all columns exactly once

Result Format

All solvors return a consistent Result namedtuple:

Result(
    solution,     # best solution found
    objective,    # objective value
    iterations,   # solver iterations (pivots, generations, etc.)
    evaluations,  # function evaluations
    status        # OPTIMAL, FEASIBLE, INFEASIBLE, UNBOUNDED, MAX_ITER
)

When to use what?

Problem Solvor
Linear constraints, continuous variables solve_lp
Linear constraints, some integers solve_milp
Boolean satisfiability solve_sat
Discrete variables, complex constraints Model
Combinatorial, good initial solution tabu_search, anneal
Combinatorial, no clue where to start evolve
Smooth, differentiable adam
Expensive black-box bayesian_opt
Assignment, matching, flow max_flow, solve_assignment
Exact cover, tiling, N-Queens solve_exact_cover

Philosophy

  1. Pure Python - no numpy, no scipy, no compiled extensions
  2. Readable - each solvor fits in one file you can actually read
  3. Consistent - same Result format, same minimize/maximize convention
  4. Practical - solves real problems, or AoC puzzles

Contributing

See CONTRIBUTING.md for development setup and guidelines.

License

Apache 2.0 License - free for personal and commercial use.

About

Optimization solvers in pure Python: LP, MILP, SAT, constraint programming, and metaheuristics. No dependencies. Local tool brought to github and modernized. 1.0 Release will use Rust for performance critical operations.

Topics

Resources

License

Contributing

Stars

Watchers

Forks

Languages