how to solve numerical issues

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建城 张

2023年12月09日 12:17

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how to solve the problem？Model contains large objective coefficients.  Consider reformulating model or setting NumericFocus parameter  to avoid numerical issues.

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  Simranjit Kaur

  • Gurobi Staff

  2026年11月13日 01:33

  This post is more than two years old. Some information may not be up to date. For current information, please check the Gurobi Documentation or Knowledge Base. If you need more help, please create a new post in the community forum, or try Gurobot, our chatbot interface offering instant, expert-level support.
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  Riley Clement

  • Gurobi Staff

  2023年12月09日 12:45

  Hi 建城 张,

  Maliheh has given a very detailed answer to this question when it was asked previously: https://support.gurobi.com/hc/en-us/community/posts/4676253771025-Large-matrix-coefficients-and-large-RHS-warning

  Also, the section of our reference manual Does my model have numerical issues? and the pages that follow it will be useful reading.

  - Riley

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  建城 张

  2023年12月09日 13:15

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  hi Riley:

  So happy that u reply me soon. i had read the article u shown me above.but unfortnately,i had try the solving ways the article given and it didnt works. could u please give me some detailed solving answer.i will appreciate it .the detailed error are shown below

  Gurobi Optimizer version 11.0.0 build v11.0.0rc2 (win64 - Windows 10.0 (19045.2))

  CPU model: AMD Ryzen 5 4500U with Radeon Graphics, instruction set [SSE2|AVX|AVX2]
  Thread count: 6 physical cores, 6 logical processors, using up to 6 threads

  Optimize a model with 724 rows, 724 columns and 1445 nonzeros
  Model fingerprint: 0x5ee04fa0
  Variable types: 0 continuous, 724 integer (724 binary)
  Coefficient statistics:
    Matrix range     [1e+00, 1e+00]
    Objective range  [6e+02, 1e+10]
    Bounds range     [1e+00, 1e+00]
    RHS range        [1e+00, 1e+00]
  Warning: Model contains large objective coefficients
           Consider reformulating model or setting NumericFocus parameter
           to avoid numerical issues.
  Found heuristic solution: objective 2.187660e+08

  Explored 0 nodes (0 simplex iterations) in 0.00 seconds (0.00 work units)
  Thread count was 1 (of 6 available processors)

  Solution count 1: 2.18766e+08

  Optimal solution found (tolerance 1.00e-04)
  Best objective 2.187660000000e+08, best bound 2.187660000000e+08, gap 0.0000%

  your sincerely

  -zhang

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  Riley Clement

  • Gurobi Staff

  2023年12月09日 13:30

  Hi Zhang,

  The log indicates that the solver is finding an optimal solution very quickly - almost no time at all. I would not worry about the warning for this model.

  - Riley

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  建城 张

  2023年12月09日 13:47

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  hi Riley，

  words can not express how  grateful i am to u。i try to optimize my model now and i hope the work will

  pay off. if u have any suggestions or improved guidence to my codes or my model.please tell me asap.i will appreciate it.hope u have a good day. best wish for u. my bro. 

  yours sincerely

  -zhang

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