Krypt
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Activity overview
Latest activity by Krypt-
Krypt commented,
thanks for all the help!
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Krypt commented,
I see. I will check the numerical issue. If I understood you correctly, even if the model does not have a numerical issue, we can never guarantee that we will get the same performance irrespective ...
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Krypt commented,
Riley, this is really helpful. Thank you very much!One more question, what can I try to minimize this behavior as much as possible? What are the settings that I can potentially play with?
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Krypt created a post,
Changing the order of the constraints affects performance
AnsweredI am solving an MIP. I noticed that if I change the order in which constraints are added slightly, it drastically affects the solution runtime. Currently, I have an MIPGap = 1%. One order gets to t...
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Krypt commented,
Hi David, I thought negative reduced cost indicates that adding the variable would improve the objective value, as many textbooks say. I still do not understand why would the variable have negative...
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Krypt commented,
hi, could you please point out some gurobi-python example of adding columns? also, i am wondering if this approach reoptimizes using the current solution or solves the whole problem from scratch
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Krypt created a post,
Adding new columns to existing model
Hello, I am trying to implement column generation. Right now, I am redefining the model and solving it from scratch every time I generate a new column, this is very inefficient. I am wondering if t...
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Krypt created a post,
Enforcing arc (a,b)=1 in branch and price algorithm for routing problem
AnsweredI am trying to solve a vehicle routing problem using a branch and price algorithm. At the restricted master problem (RMP), we consider two branches: we enforce an arc (a,b)=0 and (a,b)=1 (I am fo...
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Krypt created a post,
Modeling variable multiplication and/or divisions
AnsweredHi, My optimization model contains constraints with variable multiplications and divisions. For example, I want to add constraints like below: mdl.addConstr(x/y >= (1/z) + epsilon)mdl.addConstr(x/(...
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Krypt commented,
Thank you!