A.Omidi

1. Community
2. Modeling

Dear support team, I am trying to work on a scheduling problem based on its polyhedron reformulations. For that, I would like to reformulate a BigM model into its equivalent Convex hull, (CH),  for...

• A.Omidi
• August 17, 2024 08:35
• 2 followers
• 11 comments
• 0 votes

1. Community
2. Programming

Dear community team, I'm trying to write a constraint in the following form: $$(a_j * (s_j!)) / L \leq 1-\gamma$$ Where \(\texttt{a}\) and \(\texttt{gamma}\) are constants and \(\texttt{s}\) and \(...

• A.Omidi
• October 31, 2020 09:27
• Edited
• 3 followers
• 4 comments
• 0 votes

1. Community
2. Programming

Dear support team, I'm working on an optimization problem (MIP) which in the medium/large scale takes too much time to solve optimality. Then I tried to use Gurobi heuristic parameter to invoke a f...

• A.Omidi
• May 01, 2020 11:52
• Edited
• 2 followers
• 1 comment
• 0 votes

1. Community
2. Programming

Dear support team,   I'm trying to solve a scheduling problem using Gurobi 9. The model is solved and the optimal solution is found. Now, I would like to use a heuristic (which an instance could be...

• A.Omidi
• March 30, 2020 10:28
• 2 followers
• 1 comment
• 0 votes

1. Community
2. Systems

Dear support team,   I'm trying to solve a large scale optimization problem using Gurobi solver (V.9) on my local machine. As I have not accessed to an academic licence for Gurobi, I will need to u...

• A.Omidi
• March 24, 2020 22:05
• 2 followers
• 1 comment
• 0 votes

1. Community
2. Algorithms

Dear community team, I have tried to solve a special knapsack problem which contains an inequality with binary parameters. AFAIK, cover cuts families can be applied to solve the standard knapsack ...

• A.Omidi
• October 13, 2019 12:09
• 2 followers
• 2 comments
• 0 votes

1. Community
2. Algorithms

Dear support team, I was trying to solve a MIP using Gurobi and Java. I will need to turn off all pre-solving, heuristics and separating options and solve the problem using pure Branch and Bound. T...

• A.Omidi
• August 09, 2019 22:47
• 4 followers
• 6 comments
• 0 votes

1. Community
2. Programming

Hello support team, I define an integer variable as following: GRBVar[][] start = new GRBVar[mach.length][item.length]; for (int m = 0; m < mach.length; m++) { for (int k = 0; k < item.leng...

• A.Omidi
• May 20, 2019 10:42
• 2 followers
• 2 comments
• 0 votes

1. Community
2. Programming

Hello support team, I have worked on the transfer a GAMS/Gurobi model into the Gurobi Java API. The GAMS code is: Binary variable rank(i,k);Equations c1,c2;c1(k).. sum(i, rank(i,k)) =e= 1;c2(i).....

• A.Omidi
• April 21, 2019 16:56
• 2 followers
• 2 comments
• 0 votes

1. Community
2. Programming

Hello, I want to use SOS_type_1 in my model in Java language. I defined variable "rank" as the below form: // Definition variable rank[i][k]GRBVar[][] rank = new GRBVar[item.length][item.length];fo...

• A.Omidi
• April 06, 2019 10:02
• 2 followers
• 4 comments
• 0 votes