Xuan Lin

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Gurobi-versary
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  • Total activity 34
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Activity overview

Latest activity by Xuan Lin

  • Xuan Lin commented,

    1. Community
    2. Algorithms
    3. An empty callback function makes the solver unable to find any feasible solution

    Hi Jaromił, Thank you for the explanation! I have a follow-up question regarding this issue. Are the techniques disabled by activating LazyConstraints inherently incompatible with lazy constraints,...

  • Xuan Lin created a post,

    An empty callback function makes the solver unable to find any feasible solution

    Awaiting user input
    1. Community
    2. Algorithms

    Hi, I am trying to implement the Branch and Benders Cut algorithm using callback functions. My simplified code setup has: // master.cpp file// Initialize the master problem classMaster::Master(){  ...

    • Xuan Lin
    • Edited
    • 2 followers
    • 3 comments
    • 0 votes

  • Xuan Lin commented,

    1. Community
    2. Algorithms
    3. Problem with enlarging the model

    Hi Riley, Thanks for the answer! I personally haven't used any GPU-based QP solver. I have heard about some research to accelerate QP solvers using GPUs, for example, this one. I think ADMM is know...

  • Xuan Lin commented,

    1. Community
    2. Algorithms
    3. Nodes in MIP logging

    Hi Jaromił, Thanks for the answer! I actually didn't know that QPs can be solved with simplex. May I ask a minor question: does the column "unexplored nodes" always goes to 0 as the algorithm termi...

  • Xuan Lin commented,

    1. Community
    2. Algorithms
    3. Nodes in MIP logging

    Hi Jaromił,   Thanks for the answer! The column It/Node shows the average number of Simplex iterations performed per node, i.e., the average number of Simplex iteration to solve a problem A to opt...

  • Xuan Lin created a post,

    Nodes in MIP logging

    Answered
    1. Community
    2. Algorithms

    Hi, I have a question regarding the explored nodes after reading the MIP Logging. I will start with my understanding of Branch and Bound: Initialize an empty list of relaxed problems L=[]. Put root...

    • Xuan Lin
    • Edited
    • 2 followers
    • 5 comments
    • 0 votes

  • Xuan Lin commented,

    1. Community
    2. Algorithms
    3. Problem with enlarging the model

    Hi Riley, Thanks for the answer! I think using simplex instead of concurrent solvers helps to reduce memory usage. I also managed to reduce the model size by improving the formulation. I have a mor...

  • Xuan Lin created a post,

    Problem with enlarging the model

    Answered
    1. Community
    2. Algorithms

    Hi, I am solving MILP models and trying to scale them up. When I try a smaller model like below, Gurobi quickly goes to the branch and bound procedure which solves the model very fast. I record one...

    • Xuan Lin
    • Edited
    • 2 followers
    • 4 comments
    • 0 votes

  • Xuan Lin commented,

    1. Community
    2. Programming
    3. Fast constraint rhs modification

    Hi Riley, Yes, what you said is correct, that is why the code I put here is a simplified model for debugging purposes. I have the complete model (~400 lines) that sets lb=ub to various nonzero valu...

  • Xuan Lin commented,

    1. Community
    2. Programming
    3. Fast constraint rhs modification

    Hi Riley, Thanks for the feedback and suggestions! I apologize for the complicated code, as I tried to keep the structure of the model to represent the original one. The x0_new[i_x] is always 0 - t...