gurobi

问题 I have a question about how to change a coefficient in the constraint. For example, I have the following constraint: lhs.addTerms(temp, x[i]) model.addConstr(cost, GRB.EQUAL, 1.0/a*lhs, 'cost_cons') If I want change "temp" in the next iteration, how to modify the model? Thanks very much 回答1: Could you give a little more information? What I think you want to do is change the coefficients of x[i] in that particular constraint. If that's it, then you should save the constraint by assigned it to

问题 I've constructed a window in pyqt5, which by clicking on "optimize" button, the program reads the "Gurobi-model.lp" file(click here to get the file), and optimizes it by the help of the Gurobi software. How can I display the logs of the Gurobi on a QTextBrowser? I found some functions in the Gurobi such as OutputFlag, LogFile, LogToConsole. However, I searched a lot, and I didn't understand these functions might be helpful for me or not. Anybody can help me in this regard? For those who are

问题 I am a beginner in gurobipy. I would like to add an inverted indicator constraint. Indicator constraint is nothing but depending on a binary variable a constraint does or does not hold. In gurobipy this is written as model.addConstr((x == 1) >> (y + z <= 5)) where x is a binary variable, y and z are integer variables. This statement says that if x is True then the constraint y+z <= 5 holds. But I would like to have an inverted constraint like this. If y+z <= 5 then x == 1. But gurobi does not

问题 I want to analyze whether the boundary should increase or reduce in Constraints in a programming problem: The following is simplified problem. V[(i,t)] is decision variable and S[i] is input. I want to know if the obj increases or reduces when increasing one unit of S[i]`. I know may the shadow price and marginal cost are for decision variable not inputs. In Gurobi, Dual value (also known as the shadow price) can use the Pi function. for t in range(T): for i in range(I): m.addConstr(V[(i,t)]

问题 I want to analyze whether the boundary should increase or reduce in Constraints in a programming problem: The following is simplified problem. V[(i,t)] is decision variable and S[i] is input. I want to know if the obj increases or reduces when increasing one unit of S[i]`. I know may the shadow price and marginal cost are for decision variable not inputs. In Gurobi, Dual value (also known as the shadow price) can use the Pi function. for t in range(T): for i in range(I): m.addConstr(V[(i,t)]

问题 I want to analyze whether the boundary should increase or reduce in Constraints in a programming problem: The following is simplified problem. V[(i,t)] is decision variable and S[i] is input. I want to know if the obj increases or reduces when increasing one unit of S[i]`. I know may the shadow price and marginal cost are for decision variable not inputs. In Gurobi, Dual value (also known as the shadow price) can use the Pi function. for t in range(T): for i in range(I): m.addConstr(V[(i,t)]

问题 I need to optimize a model with different sets of constraints, but a subset of those constraints will be the same for each model. My idea was to build a base model with all the variables and all the constraints that will be needed every time. However, it doesn't look like the Gurobi Model.copy() method copies variables the way I imagined. Here's a very simplified version of what I am hoping to do that shows the error I'm getting. >>> from gurobipy import Model >>> m0 = Model("test") >>> v =

问题 I need to optimize a model with different sets of constraints, but a subset of those constraints will be the same for each model. My idea was to build a base model with all the variables and all the constraints that will be needed every time. However, it doesn't look like the Gurobi Model.copy() method copies variables the way I imagined. Here's a very simplified version of what I am hoping to do that shows the error I'm getting. >>> from gurobipy import Model >>> m0 = Model("test") >>> v =

问题 I would like to use Gurobi in a C++ project I have in Eclipse. I tried multiple manuals/tutorials (including THIS on how to do the same in Visual Studio) to add the hook up the Gurobi files with Eclipse/GCC, but I just couldn't make it work. I feel like I don't understand enough how these things should work in the first place. In my Gurobi folder I have 3 folders, that in my opinion are important: include (with .h files), lib (with .lib files and NO .so or .a files) and src (with .cpp & .h

问题 I am facing a problem where I must call the Gurobi engine iteratively. Between runs, I have to update the constant term in some of the constraints. I check the manual book in which I find GRBModel::chgCoeff() could be used to change the coefficient of variables in the constraint but there is no function related to changing the constant term. Any idea to do that? Thank you! 回答1: I think that you have to set the RHS attribute of the Linear Constraint object. So, if constr is your constraint,