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#include <iostream>
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#include <lemon/lp_glpk.h>
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using namespace lemon;
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int main()
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{
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//The following example is taken from the documentation of the GLPK library.
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//See it in the GLPK reference manual and among the GLPK sample files (sample.c)
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LpGlpk lp;
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typedef LpGlpk::Row Row;
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typedef LpGlpk::Col Col;
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lp.max();
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Col x1 = lp.addCol();
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Col x2 = lp.addCol();
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Col x3 = lp.addCol();
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//One solution
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// Row p = lp.addRow();
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// Row q = lp.addRow();
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// Row r = lp.addRow();
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// lp.setRow(p,x1+x2+x3 <=100);
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// lp.setRow(q,10*x1+4*x2+5*x3<=600);
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// lp.setRow(r,2*x1+2*x2+6*x3<=300);
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//A more elegant one
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//Constraints
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lp.addRow(x1+x2+x3 <=100);
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lp.addRow(10*x1+4*x2+5*x3<=600);
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lp.addRow(2*x1+2*x2+6*x3<=300);
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//Nonnegativity of the variables
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lp.colLowerBound(x1, 0);
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lp.colLowerBound(x2, 0);
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lp.colLowerBound(x3, 0);
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//Objective function
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lp.setObj(10*x1+6*x2+4*x3);
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lp.solve();
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if (lp.primalStatus()==LpSolverBase::OPTIMAL){
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printf("Z = %g; x1 = %g; x2 = %g; x3 = %g\n",
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lp.primalValue(),
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lp.primal(x1), lp.primal(x2), lp.primal(x3));
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}
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else{
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std::cout<<"Optimal solution not found!"<<std::endl;
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}
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//Here comes the same problem written in C using GLPK API routines
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// LPX *lp;
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// int ia[1+1000], ja[1+1000];
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// double ar[1+1000], Z, x1, x2, x3;
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// s1: lp = lpx_create_prob();
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// s2: lpx_set_prob_name(lp, "sample");
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// s3: lpx_set_obj_dir(lp, LPX_MAX);
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// s4: lpx_add_rows(lp, 3);
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// s5: lpx_set_row_name(lp, 1, "p");
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// s6: lpx_set_row_bnds(lp, 1, LPX_UP, 0.0, 100.0);
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// s7: lpx_set_row_name(lp, 2, "q");
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// s8: lpx_set_row_bnds(lp, 2, LPX_UP, 0.0, 600.0);
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// s9: lpx_set_row_name(lp, 3, "r");
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// s10: lpx_set_row_bnds(lp, 3, LPX_UP, 0.0, 300.0);
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// s11: lpx_add_cols(lp, 3);
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// s12: lpx_set_col_name(lp, 1, "x1");
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// s13: lpx_set_col_bnds(lp, 1, LPX_LO, 0.0, 0.0);
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// s14: lpx_set_obj_coef(lp, 1, 10.0);
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// s15: lpx_set_col_name(lp, 2, "x2");
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// s16: lpx_set_col_bnds(lp, 2, LPX_LO, 0.0, 0.0);
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// s17: lpx_set_obj_coef(lp, 2, 6.0);
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// s18: lpx_set_col_name(lp, 3, "x3");
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// s19: lpx_set_col_bnds(lp, 3, LPX_LO, 0.0, 0.0);
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// s20: lpx_set_obj_coef(lp, 3, 4.0);
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// s21: ia[1] = 1, ja[1] = 1, ar[1] = 1.0; /* a[1,1] = 1 */
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// s22: ia[2] = 1, ja[2] = 2, ar[2] = 1.0; /* a[1,2] = 1 */
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// s23: ia[3] = 1, ja[3] = 3, ar[3] = 1.0; /* a[1,3] = 1 */
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// s24: ia[4] = 2, ja[4] = 1, ar[4] = 10.0; /* a[2,1] = 10 */
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// s25: ia[5] = 3, ja[5] = 1, ar[5] = 2.0; /* a[3,1] = 2 */
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// s26: ia[6] = 2, ja[6] = 2, ar[6] = 4.0; /* a[2,2] = 4 */
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// s27: ia[7] = 3, ja[7] = 2, ar[7] = 2.0; /* a[3,2] = 2 */
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// s28: ia[8] = 2, ja[8] = 3, ar[8] = 5.0; /* a[2,3] = 5 */
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// s29: ia[9] = 3, ja[9] = 3, ar[9] = 6.0; /* a[3,3] = 6 */
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// s30: lpx_load_matrix(lp, 9, ia, ja, ar);
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// s31: lpx_simplex(lp);
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// s32: Z = lpx_get_obj_val(lp);
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// s33: x1 = lpx_get_col_prim(lp, 1);
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// s34: x2 = lpx_get_col_prim(lp, 2);
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// s35: x3 = lpx_get_col_prim(lp, 3);
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// s36: printf("\nZ = %g; x1 = %g; x2 = %g; x3 = %g\n", Z, x1, x2, x3);
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// s37: lpx_delete_prob(lp);
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// return 0;
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return 0;
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}
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