ahmad alanaqreh

I 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...

In 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...

I 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...

Hi  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,...

I 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...

I 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...

I 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...

I 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...

I have a minimization model as follow :   \ LP format - for model browsing. Use MPS format to capture full model detail.Minimize Z + 0 y6 + 0 y17 + 0 y25 + 0 y32 + 0 y37Subject To cut1: - Z - y1 -...

Hi  I have a model which contains variables and parameters in this way below with gp.Model ( "masterproblem" ) as model: Z_var = model.addVar ( name="Z") y = {} for a in range ( 1, n + 1 )...