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Another bug in MIP presolve

Open jajhall opened this issue 1 year ago • 2 comments

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 avatar Oct 04 '24 17:10 jajhall

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.

fwesselm avatar Oct 07 '24 11:10 fwesselm

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

jajhall avatar Oct 07 '24 12:10 jajhall

Fixed by #2151

jajhall avatar Jan 27 '25 17:01 jajhall