[Help-glpk] Name index discrepancies?

[Joey Rios]

I am solving a binary integer program and then, after examining the solution, I modify the data and solve again.   I am using the GLPK API 4.19.

My question is regarding the name index functions.  I am essentially doing something like this (I think these are the important/relevant parts of the code, if more is necessary, please let me know):


/* Set up the problem */
bip = lpx_read_model(argv[INDEX_MODL], argv[INDEX_DATA], NULL);
glp_init_smcp(simplex_control_params);

/* Create the name index */
glp_create_index(bip);

/* To illustrate my confusion */
printf("COLUMN w[FDX1857_1511,OAK,169] has index %d\n", glp_find_col(bip, "w[FDX1857_1511,OAK,169]"));

/* Solve */
glp_simplex(bip, simplex_control_params);
lpx_integer(bip);

/* 'Delay_Costs' is my objective function */
i = glp_find_row(bip, "Delay_Costs");
len = glp_get_mat_row(bip, i, ind, val);

/* Print out each column name present in the objective fcn */
for( j = 1; j <= len; j++)
   printf("  Row %d Col %d variable %s\n", i, j, glp_get_col_name(bip, ind[j]));

/* To further illustrate */
printf("COLUMN w[FDX1857_1511,OAK,169] has index %d\n", glp_find_col(bip, "w[FDX1857_1511,OAK,169]"));




This program will output something like this:


COLUMN w[FDX1857_1511,OAK,169] has index 744
...
Row 1 Col 744 variable w[N50LG_292,MCC,50]
Row 1 Col 745 variable w[N50LG_292,MCC,49]
...
COLUMN w[FDX1857_1511,OAK,169] has index 744


So my question is: does the ordinal # of the column (as returned by glp_find_col()) not correspond to the column number as I step through the objective function as above?  Is this a bug or a misunderstanding on my part?  Any clarification or guidance appreciated... this issue has taken up a good many hours for me already!  If any further information would be helpful, please just let me know, I'd be happy to provide it.

Thanks in advance...

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