Fabio David

Gurobi-versary
Conversationalist
Curious
  • Total activity 16
  • Last activity
  • Member since
  • Following 0 users
  • Followed by 0 users
  • Votes 1
  • Subscriptions 5

Activity overview

Latest activity by Fabio David

  • Fabio David commented,

    1. Community
    2. Modeling
    3. Efficient way to avoid quadratic constraints

    Thank you, Jaromił. Your suggestion had a slightly better performance than my best implementation, probably because it had fewer restrictions. Just a question: Is it more efficient or correct to...

  • Fabio David commented,

    1. Community
    2. Modeling
    3. Efficient way to avoid quadratic constraints

    Thanks for the quick reply (as always)! I know there is no magic formula for this, I understand that it is necessary to implement and test to see which is the best option for each case. I made some...

  • Fabio David created a post,

    Efficient way to avoid quadratic constraints

    Answered
    1. Community
    2. Modeling

    To solve a specific problem, I have created a set of integer decisions variables S[i,k] with lb=0 and ub=640, with a size of approximately 1000 indices, but in some instances it can reach tens of t...

    • Fabio David
    • 2 followers
    • 4 comments
    • 0 votes

  • Fabio David commented,

    1. Community
    2. Modeling
    3. How does the "ScaleFlag" option work?

    Hi Maliheh, Thank you for your quick response. I had checked out this option on https://www.gurobi.com/documentation/9.5/refman/scaleflag.html. However, the reference documentation for version 10.0...

  • Fabio David created a post,

    How does the "ScaleFlag" option work?

    Answered
    1. Community
    2. Modeling

    Using grbtune to analyze my problem, it suggested using the option ScaleFlag=1. This significantly reduced the execution time for solving it. Looking at the documentation on Gurobi site, it was not...

    • Fabio David
    • 5 followers
    • 4 comments
    • 0 votes

  • Fabio David commented,

    1. Community
    2. Modeling
    3. MCKP (multiple-choice knapsack problem) with many items

    Sorry for the long response time. I followed all the suggestions, but it didn't achieve much better results. I decided to change my approach.Anyway, I really appreciate your suggestions, as they ha...

  • Fabio David created a post,

    MCKP (multiple-choice knapsack problem) with many items

    Answered
    1. Community
    2. Modeling

    Hi,I have a problem that can be modeled as a MCKP (multiple-choice knapsack problem). It is possible to calculate all items i in advance (python script) and classify them in C classes. Each item is...

    • Fabio David
    • 2 followers
    • 2 comments
    • 0 votes

  • Fabio David commented,

    1. Community
    2. Programming
    3. Most efficient way to solve multiple objectives

    Hi Jaromil/Gurobi staff, Thanks for your explanation. After running some tests, the blended approach seems to be much faster than the hierarquical method, at least in my application. The problem no...

  • Fabio David created a post,

    Most efficient way to solve multiple objectives

    Answered
    1. Community
    2. Programming

    Hi I'm trying to solve a MILP with multiple objectives. For example, suppose I want to min x then min y and finally min z. I would like to know which is the most efficient way to solve it. Should I...

    • Fabio David
    • 2 followers
    • 3 comments
    • 0 votes

  • Fabio David created a post,

    Python filter list with mathematical operation in add.constr -> NotImplementedError

    1. Community
    2. Programming

    I need to add a constraint so that my decision var must be in a interval, so I tried to filter somethong like this: m.addConstrs( (O[i] == 1 for i in L if x[i] >= a[i] and x[i] <= a[i]+b), "co" ) U...

    • Fabio David
    • 3 followers
    • 2 comments
    • 0 votes