arXiv Machine Learning

Imperfect Is Perfect: Learned Column Prefilling for Branch-Price-and-Cut

arXiv:2610. 21001v1 Announce Type: new Abstract: Column generation folklore warns that initial columns hurt: a warm start may bias the dual and slow the root of branch-price-and-cut.

arXiv Machine Learning
3d ago

Learning Warm Starts for the Simplex Method from Measured Solver Cost

The paper introduces CostStart, a method that learns warm starts for the simplex algorithm by predicting which variables will be basic at optimality and then selecting the number of predicted columns, algorithm, and pricing rule based on measured instruction counts. Experiments on 25 classes of linear programs show that while a strong supervised predictor can reduce dual simplex iterations by two thirds, it only cuts solve time by one third; CostStart mitigates this gap and roughly halves solve time compared to the solver’s default start, outperforming two published methods on unseen problems up to four times larger.

By Felix Parker, Danielle A. Ripsman, Emmett Springer, Kimia Ghobadi
arXiv Machine Learning
Sep 7

GNN-Guided Graph Coarsening and Adaptive QUBO Penalties for the Capacitated Vehicle Routing Problem with Time Windows on a Quantum Annealer

The paper presents a method for reducing the size of Quadratic Unconstrained Binary Optimization (QUBO) models used to solve the Capacitated Vehicle Routing Problem with Time Windows (CVRPTW) on quantum annealers. It introduces adaptive penalty calibration to improve constraint satisfaction and replaces hand‑tuned merge heuristics with a graph neural network (GNN) that consistently achieves higher feasibility across Solomon benchmark families. Experiments on simulated annealing and a D‑Wave Advantage2 processor show significant reductions in constraint violations and improved feasibility rates, with the QUBO size remaining 5–6 times smaller.

By Youssef Kamel Rezk, Pawe{\l} Gora
arXiv AI
Sep 16

Calibrate, Then Route: A Measured Study of Learned Request Routing for Disaggregated LLM Serving

The paper evaluates a learned request‑routing policy for disaggregated large‑language‑model serving, where compute‑heavy prefill and memory‑heavy decode stages run on separate GPU pools. Using a discrete‑event simulator and real NVIDIA A40 GPUs, the calibrated router—leveraging prompt length, predicted output length, KV‑cache pressure, and SLO class—outperforms round‑robin, least‑loaded, and length‑based heuristics, achieving the highest mean goodput (0.864) and lowest variance across three mixed, bursty arrival traces. Hardware calibration proves critical, providing a 4.5‑point goodput boost and roughly 40 % of the tail‑latency advantage, and the learned router can match round‑robin performance with one fewer GPU in certain scenarios.

By Srikanta Datta Tumkur, Jay Iyer, Mehar Simhadri, Sai Pavan Kumar, Sai Kapil Kumar, Ramesh Nampelly
arXiv Machine Learning
Sep 17

Temperon: Full-Time SAM Quality at a Third Less Wall-Clock

The paper introduces Temperon, a training strategy that uses plain SGD for the first 43% of the epoch budget and then hands off to a SAM‑wrapped Muon refiner for the remaining training. On datasets such as CIFAR‑10/100, SVHN, and Tiny ImageNet, Temperon achieves the same or better accuracy as full‑time SAM while reaching key performance targets faster and at lower cost. Ablation studies show that the Muon refiner contributes the majority of the performance gain, while the initial SGD explorer and its restarts add negligible benefit.

By Stamatis Mastromichalakis