Jack Keefer
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Latest activity by Jack Keefer
Jack Keefer created a post,
How to maximize an objective function given another objective function achieves a minimum value?
AnsweredI have an optimization problem that involves two possible objective functions. One variation of the problem involves me maximizing one of the objective functions such that the second objective func...

Jack Keefer created a post,
Code Hangs with Timeout Error in R when Calling Gurobi through Python API using reticulate
Awaiting user inputHello, I am calling Gurobi using the Python API from R using the reticulate package. In R, I have wrapped my Python call in outer functions as I perform a series of computations. However, I want to...

Jack Keefer commented,
Hello, Thank you very much for your reply. I was able to successfully being tuning with the gurobi_cl interface, and was able to set a baseline parameter "NonConvex=2". However, when I use the co...

Jack Keefer created a post,
Is there a way to fix a parameter value when using the automatic tuning tool?
AnsweredHello, There is a parameter I know makes my model solve orders of magnitude faster (PreQLinearization = 0). With it, the model takes less than 0.1 seconds to solve, without it, it won't solve in th...

Jack Keefer created a post,
Can constraints speed up solving a model? (Or would there be a better way to introduce information?)
AnsweredI am currently working a project in which I use Gurobi many times (as the inner most loop of a few nested loops). Each time, I construct a model in which I determine if an individual will participa...

Jack Keefer created a post,
How to test if a feasible solution is optimal
AnsweredI wanted to know if it was possible to use Gurobi to test if a feasible solution is the optimal solution to a nonlinear binary programming problem. Is it possible to have Gurobi use the solution I ...

Jack Keefer created a post,
Estimate a Coefficient from Objective Function so Optimization Result Fits Data (Tuning Model)
OngoingI am working on a problem that is a modified version of a twoknapsack knapsack problem. I am able to find the optimal choices by using Gurobi. However, I would like to estimate a coefficient that ...

Jack Keefer commented,
That was probably my mistake as there was a typo in what I typed up in question (44) as I wrote it pretty quickly to post here. Function \(F\) should really be a function of \(\mathbf{\lambda}, \ma...

Jack Keefer commented,
Hello, Thank you very much for your timely and helpful reply. I rewrote the problem, but wanted to confirm that I understood your instructions. For the function referred to a \(F(X_{i}, \lambda_{i}...

Jack Keefer created a post,
Can a Gurobi Produce Solve this nonlinear binary integer problem?
AnsweredHello, I am attempting to solve this problem where all variables, besides the Xi and Yi choice variables, are fixed/observed in data. Note than equation (43) and (44) are the same, simply reformula...