On Fri, 2015-09-04 at 11:06 +0200, Yaser Tohidi wrote: > No, I have assigned a name to jth column. When I print "name" the name > of jth column is shown. > The problem is that I want to use glp_find _col. I use the same "name" > coming from glp_get_col_name but glp_find_col returns zero. > I hope it's clear now. > > On Thu, Sep 3, 2015 at 8:53 PM, Andrew Makhorin <m...@gnu.org> wrote: > On Thu, 2015-09-03 at 16:36 +0200, Yaser Tohidi wrote: > > I cannot use "glp_find_col". It retrieves zero always even I > use the > > following code. I also create index at the beginning by > > glp_create-index. > > > > > > const char *name; > > name= glp_get_col_name(lp1,j); > > i=glp_find_col(lp1,name); > > > > > > > > Please let me know what I'm missing. > > > > > Looks like you didn't assign a name to j-th column, so > glp_get_col_name > returns NULL. > > > > >
Please check you code. The following example works fine for me: /* sample.c */ #include <stdio.h> #include <stdlib.h> #include <glpk.h> int main(void) { glp_prob *lp; int ia[1+1000], ja[1+1000]; double ar[1+1000], z, x1, x2, x3; s1: lp = glp_create_prob(); s2: glp_set_prob_name(lp, "sample"); s3: glp_set_obj_dir(lp, GLP_MAX); s4: glp_add_rows(lp, 3); s5: glp_set_row_name(lp, 1, "p"); s6: glp_set_row_bnds(lp, 1, GLP_UP, 0.0, 100.0); s7: glp_set_row_name(lp, 2, "q"); s8: glp_set_row_bnds(lp, 2, GLP_UP, 0.0, 600.0); s9: glp_set_row_name(lp, 3, "r"); s10: glp_set_row_bnds(lp, 3, GLP_UP, 0.0, 300.0); s11: glp_add_cols(lp, 3); s12: glp_set_col_name(lp, 1, "x1"); s13: glp_set_col_bnds(lp, 1, GLP_LO, 0.0, 0.0); s14: glp_set_obj_coef(lp, 1, 10.0); s15: glp_set_col_name(lp, 2, "x2"); s16: glp_set_col_bnds(lp, 2, GLP_LO, 0.0, 0.0); s17: glp_set_obj_coef(lp, 2, 6.0); s18: glp_set_col_name(lp, 3, "x3"); s19: glp_set_col_bnds(lp, 3, GLP_LO, 0.0, 0.0); s20: glp_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: glp_load_matrix(lp, 9, ia, ja, ar); s31: glp_simplex(lp, NULL); s32: z = glp_get_obj_val(lp); s33: x1 = glp_get_col_prim(lp, 1); s34: x2 = glp_get_col_prim(lp, 2); s35: x3 = glp_get_col_prim(lp, 3); s36: printf("\nz = %g; x1 = %g; x2 = %g; x3 = %g\n", z, x1, x2, x3); #if 1 { int j; const char *name; glp_create_index(lp); for (j = 1; j <= 3; j++) { name = glp_get_col_name(lp, j); printf("name = |%s| find_col = %d\n", name, glp_find_col(lp, name)); } } #endif s37: glp_delete_prob(lp); return 0; } /* eof */ mao@corvax:~/Desktop$ gcc sample.c -lglpk mao@corvax:~/Desktop$ ./a.out GLPK Simplex Optimizer, v4.45 3 rows, 3 columns, 9 non-zeros * 0: obj = 0.000000000e+00 infeas = 0.000e+00 (0) * 2: obj = 7.333333333e+02 infeas = 0.000e+00 (0) OPTIMAL SOLUTION FOUND z = 733.333; x1 = 33.3333; x2 = 66.6667; x3 = 0 name = |x1| find_col = 1 name = |x2| find_col = 2 name = |x3| find_col = 3 mao@corvax:~/Desktop$ _______________________________________________ Help-glpk mailing list Help-glpk@gnu.org https://lists.gnu.org/mailman/listinfo/help-glpk