Zheren Zhang
- Total activity 19
- Last activity
- Member since
- Following 0 users
- Followed by 0 users
- Votes 0
- Subscriptions 5
Activity overview
Latest activity by Zheren Zhang-
Zheren Zhang created a post,
additional argument in callback function
AnsweredHi I'm trying to implement a callback function in which a list of variables that not belong to the model has to be updated when a MIP solution is found. My approach is to add the virable as the ar...
-
Zheren Zhang commented,
Hi Jaromił Thank you for your tipps. I will follow your suggestion and report the issue or try to implement a convex relaxation like McCormick relaxation if the values of Pi are still unexpected. B...
-
Zheren Zhang commented,
Hi The model of the primal and dual subproblem is based on the paper "A Benders decomposition approach to transmission expansion planning considering energy storage" without parallel installation...
-
Zheren Zhang commented,
Hi Jaromił I've expected that some Pi of the constraints which contain the fixed complicated variable of the original problem are not zero, like the LP. However, after adding the quadratic constrai...
-
Zheren Zhang commented,
Hi Jaromił You have understand my issue correctly despite my unclear discription. I've followed the tutorial of the RME and found out that are too many parameters to reproduce. Am I allowed to send...
-
Zheren Zhang created a post,
Retrieving the dual value from a model with quadratic constraints
AnsweredHi I've implemented a LP benders subproblem which fills the strong duality and retrieved the dual values of its constraints properly by calling Pi. Now I'm extending this benders subproblem to a NL...
-
Zheren Zhang commented,
Hi Mario I've uploaded the complete model and the Benders approach, which could be necessary, via the link you provide. I will work on the modification of the Benders cut using your tipps. Thank yo...
-
Zheren Zhang commented,
Hi Mario I do get two significantly different optimal objective values after setting IntegralityFocus = 1, while the worse one is as same as the solution of the Benders approach. Since the sense of...
-
Zheren Zhang commented,
Hi Mario Both solutions are feasible. In the solution of Gurobi, the decision variables do deviate by a value less than 1e-5, while the objective value of two approaches are significantly different...
-
Zheren Zhang commented,
Hi Mario You have a proper concept of my setup despite my unclear discription. What I should have mentioned is that the subproblems of my model are always feasible and there are no multiple optimal...