Rolf van der Hulst

🔄 Updated Arxiv Paper

Title: Implied Integrality in Mixed-Integer Optimization
Authors: Rolf van der Hulst, Matthias Walter

Read more: https://arxiv.org/abs/2504.07209

At least on Linux there seem to exist specialized fast timing functions: see stackoverflow.com/a/47003703 , which recommends to use 'clock_gettime()' and claims it only takes 3-5 nanoseconds on their system. I think it is likely that alternative calls exist in other operating systems.

What kind of crazy FPS are you running at where a syscall is too expensive? In my experience, most syscalls take on the order of 100 - 1000 cycles, which would take less than a microsecond on a modern cpu.

This is now out, we're super proud to have won the Land-Doig MIP competition prize for our algorithm for mixed-integer quadratic optimization!

passagemath-cmr passagemath: Combinatorial matrix recognition

passagemath 10.5.27 contains (a preliminary version of) the new package passagemath-cmr, an interface to the Combinatorial Matrix Recognition library by Matthias Walter et al., implementing Seymour's decomposition of TU matrices etc.
pypi.org/project/pass...
#Python #SageMath #OpenSource #MathSky

If you are checking out Cargo, I would also check out NPM (node package manager), which is one of the most popular javascript package managers.

No of course not! I would say the opposite; the fact that it is open source helps because you can actually understand what is happening, as long as you take the time to figure it out.

I was mostly just talking about understanding the code, not just the parameters. I agree that it is annoying that a lot of parameters are repeated.

I spent a lot of time figuring out that a '>' should be a '<'...

What prompted me to write the comment, however, is the amount of details that are involved. I doubt many users could successfully tune any solver without strong knowledge of its internals.

After attempting to tune MIR cuts in SCIP for 3.5 days, I understand better why people are willing to pay so much for a commercial MIP solver license.

🔄 Updated Arxiv Paper

Title: Sparsity-driven Aggregation of Mixed Integer Programs
Authors: Liding Xu, Gioni Mexi, Ksenia Bestuzheva

Read more: https://arxiv.org/abs/2502.01192

registration for the 2025 school on column generation is now open www.gerad.ca/colloques/Co... #orms

gcg/CHANGELOG at v371 · scipopt/gcg Contribute to scipopt/gcg development by creating an account on GitHub.

The bugfix release 9.2.1 of the SCIP Optimization Suite is now available.

This brings updates to GCG, PaPILO, SCIP, and SoPlex:
- github.com/scipopt/gcg/...
- github.com/scipopt/papi...
- github.com/scipopt/scip...
- github.com/scipopt/sopl...

#orms

This is great, thanks for sharing!

Are these talks recorded and posted anywhere so that I can watch them back later?

YouTube video by Sophie Huiberts Open Problems & Diet Problems

I recorded my current talk for youtube! If you are interested in linear programming or theoretical computer science, this is for you

The #mip2025 computational competition is open! This year’s topic is finding feasible solutions for MIPs with quadratic functions. Student participation is encouraged and we may separately award outstanding student submissions. For more details, visit www.mixedinteger.org/2025/competi... #orms

I am very pleased to announce that a 1996 paper I wrote on graph coloring and column generation with Anuj Mehrotra was given a "Test of Time" award by the INFORMS Journal of Computing for papers written 1995-1999. The full citation is at pubsonline.informs.org/doi/10.1287/...