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Another bug in MIP presolve #1960

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jajhall opened this issue Oct 4, 2024 · 2 comments
Open

Another bug in MIP presolve #1960

jajhall opened this issue Oct 4, 2024 · 2 comments
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jajhall commented Oct 4, 2024 •
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In the MIP 1960.lp.txt, the optimal objective value is 681398.601399, but with presolve on, the optimal objective value is 821706.293706.

The error occurs in reduction 3346
@jajhall jajhall self-assigned this Oct 4, 2024
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fwesselm commented Oct 7, 2024 •
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I think this is caused by the fact that implied column bounds and implied row dual bounds are not updated when a variable is substituted in HPresolve::substitute. I will qualify my fix shortly.

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jajhall commented Oct 7, 2024

Great timing, as I'm about to visit the company that flagged this up! 🤩

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