Iason Liagkas

Hello guys you can ignore my previous post, the time was for parameter setting. My question is now on this run why don't I get the percentile gap per time on the log? I see the below Is there anyt...

Hello guys, I have an optimization model and It is feasible. It has one variable bound though that if I remove it it makes the problem infeasible without making any other change. Does that make sen...

I am solving a model sequentially and it is feasible in the first iteration. In the second iteration the model becomes infeasible but I get an objective function value when I run subproblem.objVal....

Hello guys, I have a model and when I do model.write() the created file contains the binary variables plenty of times and a constraint 2 times. I do not create the variables or the constraint 2 tim...

Hello guys, I am working on the Benders algorithm. I am wondering if I have a problem with a variable x with an upper bound of 1. Does that create a constraint of x<=1 on the solver? Because if tha...

Hello guys, I have a problem that all its extreme rays are 0. Do you have any idea of what could be the case? Can we check if there are numerical issues with a problem solution that produce this re...

Hello guys, What does a large matrix coefficient cause to our problem? can we say that the results will be very sensitive to coefficient values? what would be the consequences of this situation? Ki...

Hello guys, I have created a function named SP_define and inside I have formed an optimization model named SPmodel = gp.Model('SP'). On the final line of the function, I have written: return SPmode...

Hello guys, I am running the benders algo, When my subproblem is feasible I am using the following line to get the dual variable value:  gp.quicksum(BigM*deltars2kE[r,s,k]*subproblem.getConstrByNam...

Hello Guys, I am trying to code a Python function to build a model inside. The name of the function is SP_define. The function returns the model only. I run the below code. When I print the model I...