test_swiglpk.py

# swiglpk - Swig Python bindings for the GNU Linear Programming Kit (GLPK)
# Copyright (C) 2015 The Novo Nordisk Foundation Center for Biosustainability
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

from swiglpk import *
import unittest


class TestSwiglpk(unittest.TestCase):

    def test_swiglpk(self):
        print(glp_version())
        ia = intArray(1+1000); ja = intArray(1+1000);
        ar = doubleArray(1+1000)
        lp = glp_create_prob()
        glp_set_prob_name(lp, "sample")
        glp_set_obj_dir(lp, GLP_MAX)
        glp_add_rows(lp, 3)
        glp_set_row_name(lp, 1, "p")
        glp_set_row_bnds(lp, 1, GLP_UP, 0.0, 100.0)
        glp_set_row_name(lp, 2, "q")
        glp_set_row_bnds(lp, 2, GLP_UP, 0.0, 600.0)
        glp_set_row_name(lp, 3, "r")
        glp_set_row_bnds(lp, 3, GLP_UP, 0.0, 300.0)
        glp_add_cols(lp, 3)
        glp_set_col_name(lp, 1, "x1")
        glp_set_col_bnds(lp, 1, GLP_LO, 0.0, 0.0)
        glp_set_obj_coef(lp, 1, 10.0)
        glp_set_col_name(lp, 2, "x2")
        glp_set_col_bnds(lp, 2, GLP_LO, 0.0, 0.0)
        glp_set_obj_coef(lp, 2, 6.0)
        glp_set_col_name(lp, 3, "x3")
        glp_set_col_bnds(lp, 3, GLP_LO, 0.0, 0.0)
        glp_set_obj_coef(lp, 3, 4.0)
        ia[1] = 1; ja[1] = 1; ar[1] = 1.0; # a[1,1] = 1
        ia[2] = 1; ja[2] = 2; ar[2] = 1.0; # a[1,2] = 1
        ia[3] = 1; ja[3] = 3; ar[3] = 1.0; # a[1,3] = 1
        ia[4] = 2; ja[4] = 1; ar[4] = 10.0; # a[2,1] = 10
        ia[5] = 3; ja[5] = 1; ar[5] = 2.0; # a[3,1] = 2
        ia[6] = 2; ja[6] = 2; ar[6] = 4.0; # a[2,2] = 4
        ia[7] = 3; ja[7] = 2; ar[7] = 2.0; # a[3,2] = 2
        ia[8] = 2; ja[8] = 3; ar[8] = 5.0; # a[2,3] = 5
        ia[9] = 3; ja[9] = 3; ar[9] = 6.0; # a[3,3] = 6
        glp_load_matrix(lp, 9, ia, ja, ar)
        glp_simplex(lp, None)
        Z = glp_get_obj_val(lp)
        x1 = glp_get_col_prim(lp, 1)
        x2 = glp_get_col_prim(lp, 2)
        x3 = glp_get_col_prim(lp, 3)
        print("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n" % (Z, x1, x2, x3))

        self.assertAlmostEqual(Z, 733.3333333333333)
        self.assertAlmostEqual(x1, 33.333333333333336)
        self.assertAlmostEqual(x2, 66.66666666666666)
        self.assertAlmostEqual(x3, 0)

        glp_delete_prob(lp);


if __name__ == "__main__":
    unittest.main()