OR-Tools integer linear programming example (Python)

ortools_ilp_example.py

# code to solve the problem described in https://codereview.stackexchange.com/q/282605/209865
# based on https://developers.google.com/optimization/cp/cp_example

from ortools.sat.python import cp_model
from itertools import product

variable_names = list('abcdef')
coefficients = [-42, 75, -30, 80, 25, 50]
upper_bound = 150

for v in range(3001):
    for permutation in product([False, True], repeat=len(variable_names)):
        print(f'v = {v}, permutation = {permutation}')

        model = cp_model.CpModel()

        variables = [model.NewIntVar(
            1 if is_nonzero else 0,
            upper_bound if is_nonzero else 0,
            variable_name)
            for variable_name, is_nonzero in zip(variable_names, permutation)]

        model.Add(cp_model.LinearExpr.WeightedSum(
            variables, coefficients) == - (v + 1))
        model.Minimize(cp_model.LinearExpr.Sum(variables))

        solver = cp_model.CpSolver()
        status = solver.Solve(model)

        if status == cp_model.OPTIMAL:
            print(f'Minimum sum: {solver.ObjectiveValue()}, ' +
                  ', '.join(f'{variable.Name()} = {solver.Value(variable)}'
                            for variable in variables))
        elif status == cp_model.INFEASIBLE:
            print('No solution')
        else:
            print(f'Error: status = {status}')