Jacob Jin

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Latest activity by Jacob Jin
  • Jacob Jin commented,

  • Jacob Jin commented,

    Hi Jaromil,    How could I reset the coefficient of a specific variable in a specific objective function when I deal with a multi-objectives problem in Gurobi?   Thank you so much!

  • Jacob Jin commented,

    I find the point! from numpy import *import numpy as npimport pandas as pdimport gurobipy as gbfrom gurobipy import *from gurobipy import GRBfrom itertools import permutationsimport timeimport warn...

  • Jacob Jin commented,

    Hi Jaromi, I have tried your suggestion but it didn't work. The thing I can ensure is that I didn't let the sub_dual problem be preresolved when I defined the objective function in the callback fun...

  • Jacob Jin commented,

    Hi, Jaromił As for the difficulty we talked about, I realized that when I just set the sub_dual problem's presolve parameter as -1 in the callback function, the log result showed that the solver di...

  • Jacob Jin commented,

    Sorry for that. Here is the c202.txt.  https://drive.google.com/file/d/1sG4W6F2tGwZ7rTs-TVZOdHh-7FOweXYm/view?usp=sharing  Thank you!

  • Jacob Jin commented,

    Sorry, I didn't get your meaning about Could you please also incorporate this model change after the first iteration into your snippet to reproduce the issue? My core code:  https://drive.google....

  • Jacob Jin commented,

    Hi, I tried your suggestion. I feed a data which can be solved by reset method. In the first model, the sub dual problem has been solved for 231 times(6.3411 s in total) to get the final result, wh...

  • Jacob Jin commented,

    To be more specific, I use the reset method in the callback function m_sub.reset(1)# m_sub.Params.Presolve = -1start = time.time()m_sub.optimize()end = time.time()print(m_sub.Runtime)print(m_sub.o...

  • Jacob Jin commented,

    Did you try explicitly setting the Presolve parameter inside your callback before solving the sub_dual model? You could also try calling the reset method before optimizing and setting the paramete...