ahmad alanaqreh
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Recent activity by ahmad alanaqreh-
Find the variable values for different solutions by PoolSolutions
AnsweredI have a MIP and I am solving the model and collecting all the possible solutions by using PoolSolutions parameter, now I am trying to get the value of x variable for each solution but unfortunatel...
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The bounds of the variables
AnsweredI have a model where I define three variables as follows : alpha[a] = model.addVar(lb=-GRB.INFINITY, name="alpha%d" % a)beta[i, j] = model.addVar(lb=-GRB.INFINITY, ub=0, name="beta%d,%d," % (i, j))...
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change the coefficient of the variables in the objective function
AnsweredI have a model that I am solving with callback, I need to change the coefficients of the variables in the objective function from time to time, I have seen the Model.chgCoeff() to change the coeffi...
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Improve performance of constraint-adding in Gurobi Python
OngoingIn the model I am working on I have to add constraints, the constraints based on the edges of a graph, I have the decision variable x = {}for (i, j) in E: x[i, j] = model.addVar(vtype=GRB.BINAR...
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Sort Decision variables' value in Gurobi Python
AnsweredI have a decision variables list as follows : vars=[ <gurobi.Var x1,5,>, <gurobi.Var x5,1,>, <gurobi.Var x1,22,>, <gurobi.Var x22,1,>] if I want to sort the elements based on the indices of each va...
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callback with variables based on the edges of a graph
AnsweredHi I have a callback to solve a graph problem, the variable in my model is x[i,j] where (i,j) is an edge in the input graph, now the edges of the graph are defined as follow: E = gp.tuplelist([(2,...
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infeasible model om gurobi python while it is feasible on AMPL
Awaiting user inputI have the following model and if I try to optimize it on python by using gurobi solver it is infeasible while the model is feasible and the output is -2 on AMPL by using gurobi solver !! \ LP for...
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how to get the variable values by indices
AnsweredI have a list containing the values of the variable as follows: [<gurobi.Var x1,2,>, <gurobi.Var x2,1,>, <gurobi.Var x10,16,>, <gurobi.Var x16,10,>, <gurobi.Var x18,24,>, <gurobi.Var x24,18,>] wher...
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get the variable value from list
AnsweredI am using call back to solve an LP , when the where value is simplex I am saving the values of a variable in a list called "variables" and send it to a function as follows: if where == GRB.Callb...
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FarkasDual and FarkasProof
AnsweredI am trying to apply benders decomposition for a specific problem, I have to add a cut constraint in each iteration, if the subproblem feasible I am adding an optimality cut by using Pi values of t...