Tootfinder

Conversations that don't happen remote.
I stepped in the elevator - a colleague on the phone:
Him: "okay create a character for me... Yes..."
Me: which game?
Him: "Baldurs Gate 3"
Me: stepping out, "omg! I still need to finish it!"
Him: "it's our third walk through"

Hard Guarantees at a Measured Price: Entropy-Stable Learned Finite Volumes for Compressible Flow
Denis Gueyffier (ONERA -- Institut Polytechnique de Paris)
https://arxiv.org/abs/2607.20171 https://arxiv.org/pdf/2607.20171 https://arxiv.org/html/2607.20171
arXiv:2607.20171v1 Announce Type: new
Abstract: Learned solvers for compressible flow are usually compared to classical methods at equal mesh resolution rather than at equal computational cost, and they typically offer no guarantee that their solutions remain physically admissible. We present a learned finite volume scheme for the two-dimensional Euler equations on unstructured meshes, admissible by construction and with an entropy-stable interior flux. We evaluate it under protocols fixed before any computation: frozen thresholds, falsification clauses, negative controls, a factor decomposition of the learned components, and an iso-cost comparison against the refined classical baseline. The decomposition produced the central result: the guarantee machinery alone, with both learned heads switched off (the unlearned skeleton), is the strongest scheme at equal mesh on every periodic case. At equal wall-clock cost the picture inverts into a map. Learning pays robustly only on the wall case whose boundary-condition type it never saw (10.8%). Its periodic gains flip sign with the evaluation draw ( 10% on one held-out case, -12% on the hardest). The skeleton is the only method whose iso-cost gain never changes sign, at a measured overhead of 1.74x per step. The guaranteed variant completes 36 of 36 rollouts, Mach extrapolation and unseen wall included, with zero negativity events. We fix the guaranteed scheme's one remaining out-of-distribution weakness, Mach extrapolation, at inference time: with scale-invariant network inputs, a specific-entropy floor, and no retraining, the corrected arm overtakes the unconstrained arm on one Mach case, cuts its deficit on the other by a third, passes the skeleton on the unseen wall, and keeps the guarantee. A spatial gate closes the loop: activating the heads only near the walls beats both the skeleton and the corrected arm, and transfers unchanged to a second wall geometry.
toXiv_bot_toot

Something that I learned while working in the third ward is that there are a lot of ways to get into #Summerfest between noon and 3pm or 4pm but you can also get a stamp to come back through the gate. So, go get in for free with a non-perishable food item over lunch, listen to music for 20 minutes, get your hand stamped on the way back to the office and then go listen to more music after work.