Thomas Leveringhaus

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Activity overview

Latest activity by Thomas Leveringhaus

  • Thomas Leveringhaus created a post,

    Using CSC or CSR?

    1. Community
    2. Modeling

    Dear Gurobi-Team, I would like to ask whether it makes sense to think about the format in which sparse matrices are transferred to Gurobi? I assume, Gurobi will internally use any of the formats CS...

    • Thomas Leveringhaus
    • 2 followers
    • 0 comments
    • 0 votes

  • Thomas Leveringhaus commented,

    1. Community
    2. Algorithms
    3. Concurrent Optimizer and callbacks

    Thank you David!

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    • Thomas Leveringhaus
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  • Thomas Leveringhaus commented,

    1. Community
    2. Algorithms
    3. Concurrent Optimizer and callbacks

    Hi David, thank you for your answer: Then it is a feature not a bug ;-) But that is a pity for me, because I can't save the new found solution to file during optimization. Is there a special reaso...

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  • Thomas Leveringhaus commented,

    1. Community
    2. Algorithms
    3. Concurrent Optimizer and callbacks

    Or maybe Callbacks are called from alle ConcurrentMIP-Instances but maybe identifying "if where == GRB.Callback.MIPSOL" doesn't work properly in different instances?

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  • Thomas Leveringhaus commented,

    1. Community
    2. Algorithms
    3. Concurrent Optimizer and callbacks

    Hi David, I have a callback-function like this (in python): def writesolution_callback(model, where):    if where == GRB.Callback.MIPSOL: [...] # processing of the solution and creation of t...

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  • Thomas Leveringhaus commented,

    1. Community
    2. Algorithms
    3. partition heuristic and threads

    Hi David, I redeveloped/improved my optimization modell. In the past I saw improvements with the heuristic, but actually gurobi does not even start the heuristic although I set PartitionPlace to 31...

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  • Thomas Leveringhaus created a post,

    partition heuristic and threads

    Awaiting user input
    1. Community
    2. Algorithms

    Dear Gurobi-Team, I set parameter Threads to value 64 so I got: CPU model: AMD EPYC 7502 32-Core Processor, instruction set [SSE2|AVX|AVX2]Thread count: 64 physical cores, 64 logical processors, us...

    • Thomas Leveringhaus
    • 2 followers
    • 2 comments
    • 0 votes

  • Thomas Leveringhaus created a post,

    Concurrent Optimizer and callbacks

    Answered
    1. Community
    2. Algorithms

    Dear Gurobi-Team, I am using Concurrent Optimizer and callbacks and it seems to me, that callbacks are not called, although they should (or shouldn't?). In the reference manual (https://www.gurobi....

    • Thomas Leveringhaus
    • 4 followers
    • 7 comments
    • 0 votes

  • Thomas Leveringhaus commented,

    1. Community
    2. Programming
    3. confusion about adding MVar.fromlist()

    Thanks, that works :-)

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  • Thomas Leveringhaus created a post,

    confusion about adding MVar.fromlist()

    Answered
    1. Community
    2. Programming

    Dear Gurobi-Team, I tried to use MVar.fromlist() (https://www.gurobi.com/documentation/10.0/refman/py_mvar_fromlist.html) but the given example does not work: import gurobipy as gpmodel = gp.Model(...

    • Thomas Leveringhaus
    • 2 followers
    • 2 comments
    • 0 votes