[Help-glpk] Definition of boundaries

[Stefan Herbergs]

Hello everyone,

 

I just have two short questions:

 

Is it better to define boundaries with the lpx_set_col_bnds() command or to define an extra row with x > 3 or is there no difference between these ways to set a boundary. I’m asking because I have to parse an external problem description, where the boundaries are defined as extra row and it would be easier not to change that.

 

I’m having the same problem with definitions like:

Q_dot = 3

Q_dot = 7 delta_T

Which is the same as delta_T = 3/7 , but this calculations are tricky to do automatically. Do you think it would do a big difference to the calculation speed to replace these equations?

 

Regards

 

Stefan Herbergs

 

Btw. If someone is having speed problems with the branch and bound algorithm (as I had) I can recommend using a genetic algorithm instead of the branch and bound to find at least “good” solutions for the integer variables. My system is ten times faster now, but the solution is worse of course. If anyone is having questions according to that, feel free to mail me.