Re: [Help-glpk] Status us lpx_*_class

[Andrew Makhorin]

> This seems to have been come up earlier, but I am still not sure
> about the current status of the lpx_set_class/lpx_get_class API
> routines. Am I supposed to be able to change the problem type using
> these routines?

> The test case below used to pass around glpk 4.8, but it stopped
> working somewhere between.

Starting from the version 4.15 there is no need to set the problem
class explicitly. If the problem instance has at least one integer
variable, it is of MIP class, otherwise it is of LP class, so you can
use the api routine glp_get_num_int to determine the problem class.
This is normal, because LP can be considered as a particular case of
MIP. Api routines lpx_set_class and lpx_get_class are now obsolete
and kept only for backward compatibility. Lpx_set_class only checks
its parameter and then does nothing, while lpx_get_class reports the
class depending on the number of integer variables.


Andrew Makhorin