Julian Hall

icon indicating a website link https://www.maths.ed.ac.uk/school-of-mathematics/people/a-z?person=47 icon indicating an email [email protected]

icon company University of Edinburgh @ERGO-Code icon location Penicuik, Scotland

Results 551 comments of Julian Hall

Incorrect Improvement in Solution After Adding a Cut in Iterative Process

Sorry about this. Probably due to an error in presolve. I'll investigate further in due course

Incorrect Improvement in Solution After Adding a Cut in Iterative Process

This is probably because bug fixes to the MIP presolve since 1.2.0 have caused the 1.7.2 MIP presolve to take a different path and exposed a bug. In other words,...

Incorrect Improvement in Solution After Adding a Cut in Iterative Process

And if you switch off presolve?

Incorrect Improvement in Solution After Adding a Cut in Iterative Process

Closed by #2066

Missing callbacks

OK These are soon added.

Missing callbacks

If I understand correctly, as well as a blanket "enable all callbacks", you also want a callback that is executed just before the return from `Highs::run()`?

Missing callbacks

> I want an "enable all interrupt callbacks". Of course, sorry I may be able to implement them this week

Presolver incorrectly reports infeasibility in awkwardly scaled problem

Although pathological, this is an instance that's easy to explore, so @jajhall and @fwesselm may learn something from it.

Presolver incorrectly reports infeasibility in awkwardly scaled problem

I see the issue, thanks - I've just worked through this with VScode. - The equal bounds should be an integer, so that they are shifted by `boundTol` either side...

Presolver incorrectly reports infeasibility in awkwardly scaled problem

Instance added as (failing) unit test in https://github.com/ERGO-Code/HiGHS/tree/fix-2084