Hongyu Zhang
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Hongyu Zhangさんの最近のアクティビティ-
Hongyu Zhangさんが投稿を作成しました:
Getting "DUAL_INFEASIBLE" when solving a very simple linear programming problem.
回答済みHello! I am solving a simple LP problem with dual simplex and presolve. I get the model is unbounded but I couldn't see why such a model is unbounded, can it relates to numerical issues? Please hel...
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Hongyu Zhangさんがコメントを作成しました:
Hi David, Thanks for your answers. The problem attached is a smaller example, but the real problem I am going to solve is a scale-up version of this problem, so I do need to use barrier to yield be...
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Hongyu Zhangさんが投稿を作成しました:
Why Barrier report numerical trouble encountered even the ranges are not large?
進行中Hello! I am using Barrier with persovle on to solve an LP. So I rescaled the model to make the matrix and objective range relatively small. And this model is solved with dual simplex without an iss...
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Hongyu Zhangさんがコメントを作成しました:
Hi Jaromił, Thanks very much for your answer. It confirms what we have been thinking. But I have two follow-up questions hope you could answer. 1. What will Gurobi do if we set "min 0" as a fake ...
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Hongyu Zhangさんが投稿を作成しました:
How Gurobi solves a optimisation problem that doesn't have an objective?
回答済みHello! I am solving an LP optimisation problem and wondering how Gurobi solves a problem without an objective? For example, an LP problem with some inequality constraints and some equality constra...
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Hongyu Zhangさんがコメントを作成しました:
Hi Simon, Thanks for your reply. I mean to extract all coefficients of all constraints into a dense or sparse array. Kind regards, Hongyu.
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Hongyu Zhangさんが投稿を作成しました:
Retrieve constraints matrix from Gurobi or MOI or JuMP in Julia
回答済みHello! I want to retrieve an LP model in matrix form from Gurobi. I am using package JuMP in Julia. I can print all the constraints using MathOptInterface but not in matrix form. I have no idea h...