Re: [Bug-glpk] Problem in the MIP problem

[Andrew Makhorin]

>> I don't use functions glp_read_lp or glp_read_cpxlp.

>> And, I use GLP_FX (not GLP_DB) to fix bounds for the first variable.

>> So, I don't understand.

>> And, when I use lpx_write_cpxlp, I obtain this result.

>> The problem is that variables aren't integer and the first variable bound
>> is
>> displayed as 1 <= Yi0_copy <= 1

> It is strange, because glp_write_lp (lpx_write_cpxlp) writes fixed
> variables as <varname> = <fixed value>; it writes both bounds only if
> the variable is double-bounded.


> I test variable sense after this command
> glp_set_col_bnds(glpkProbPtr,id+1,GLP_FX,dlb[id],dub[id]) and this
> test show that variables are double-bounded instead of fixed

Hmm... There is something wrong. Please print the type and bounds
of the variable reported by glp_get_col_type, glp_get_col_lb, and
glp_get_col_ub immediately after glp_set_col_bnds(... GLP_FX ...).
The type reported must be GLP_FX = 5. If not, please check your code.

> The problem maybe the fact that, at the origin, variables are declared
> GLP_DB. Then after, they are declared GLP_FX creating the bug.

I do not think that this causes the bug. You can change the type and
bounds of a variable at any time.