#include #include using namespace lemon; int main() { //The following example is taken from the documentation of the GLPK library. //See it in the GLPK reference manual and among the GLPK sample files (sample.c) LpGlpk lp; typedef LpGlpk::Row Row; typedef LpGlpk::Col Col; lp.max(); Col x1 = lp.addCol(); Col x2 = lp.addCol(); Col x3 = lp.addCol(); //One solution // Row p = lp.addRow(); // Row q = lp.addRow(); // Row r = lp.addRow(); // lp.setRow(p,x1+x2+x3 <=100); // lp.setRow(q,10*x1+4*x2+5*x3<=600); // lp.setRow(r,2*x1+2*x2+6*x3<=300); //A more elegant one //Constraints lp.addRow(x1+x2+x3 <=100); lp.addRow(10*x1+4*x2+5*x3<=600); lp.addRow(2*x1+2*x2+6*x3<=300); //Nonnegativity of the variables lp.colLowerBound(x1, 0); lp.colLowerBound(x2, 0); lp.colLowerBound(x3, 0); //Objective function lp.setObj(10*x1+6*x2+4*x3); lp.solve(); printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", lp.primalValue(), lp.primal(x1), lp.primal(x2), lp.primal(x3)); //Here comes the same problem written in C using GLPK API routines // LPX *lp; // int ia[1+1000], ja[1+1000]; // double ar[1+1000], Z, x1, x2, x3; // s1: lp = lpx_create_prob(); // s2: lpx_set_prob_name(lp, "sample"); // s3: lpx_set_obj_dir(lp, LPX_MAX); // s4: lpx_add_rows(lp, 3); // s5: lpx_set_row_name(lp, 1, "p"); // s6: lpx_set_row_bnds(lp, 1, LPX_UP, 0.0, 100.0); // s7: lpx_set_row_name(lp, 2, "q"); // s8: lpx_set_row_bnds(lp, 2, LPX_UP, 0.0, 600.0); // s9: lpx_set_row_name(lp, 3, "r"); // s10: lpx_set_row_bnds(lp, 3, LPX_UP, 0.0, 300.0); // s11: lpx_add_cols(lp, 3); // s12: lpx_set_col_name(lp, 1, "x1"); // s13: lpx_set_col_bnds(lp, 1, LPX_LO, 0.0, 0.0); // s14: lpx_set_obj_coef(lp, 1, 10.0); // s15: lpx_set_col_name(lp, 2, "x2"); // s16: lpx_set_col_bnds(lp, 2, LPX_LO, 0.0, 0.0); // s17: lpx_set_obj_coef(lp, 2, 6.0); // s18: lpx_set_col_name(lp, 3, "x3"); // s19: lpx_set_col_bnds(lp, 3, LPX_LO, 0.0, 0.0); // s20: lpx_set_obj_coef(lp, 3, 4.0); // s21: ia[1] = 1, ja[1] = 1, ar[1] = 1.0; /* a[1,1] = 1 */ // s22: ia[2] = 1, ja[2] = 2, ar[2] = 1.0; /* a[1,2] = 1 */ // s23: ia[3] = 1, ja[3] = 3, ar[3] = 1.0; /* a[1,3] = 1 */ // s24: ia[4] = 2, ja[4] = 1, ar[4] = 10.0; /* a[2,1] = 10 */ // s25: ia[5] = 3, ja[5] = 1, ar[5] = 2.0; /* a[3,1] = 2 */ // s26: ia[6] = 2, ja[6] = 2, ar[6] = 4.0; /* a[2,2] = 4 */ // s27: ia[7] = 3, ja[7] = 2, ar[7] = 2.0; /* a[3,2] = 2 */ // s28: ia[8] = 2, ja[8] = 3, ar[8] = 5.0; /* a[2,3] = 5 */ // s29: ia[9] = 3, ja[9] = 3, ar[9] = 6.0; /* a[3,3] = 6 */ // s30: lpx_load_matrix(lp, 9, ia, ja, ar); // s31: lpx_simplex(lp); // s32: Z = lpx_get_obj_val(lp); // s33: x1 = lpx_get_col_prim(lp, 1); // s34: x2 = lpx_get_col_prim(lp, 2); // s35: x3 = lpx_get_col_prim(lp, 3); // s36: printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", Z, x1, x2, x3); // s37: lpx_delete_prob(lp); // return 0; return 0; }