arXiv Machine Learning

TreeWalker: Partial Evaluation for Grouped Tree-Ensemble Inference

TreeWalker is a method for efficiently evaluating tree‑ensemble models on groups of rows that share many feature values. By treating constant features as static and varying features as dynamic, it walks each tree only once per group, partitions row bitmasks at varying splits, and skips empty subtrees, achieving significant speedups over row‑independent traversal. Experiments on Intel and Arm CPUs show up to 9× speedup for large group sizes, with outputs matching existing libraries to within round‑off limits.

arXiv Computation and Language
Oct 12

PreSTO: Predictive Subtree Prefetching for Fast LLM Power Sampling

PreSTO introduces Predictive SubTree Prefetching to accelerate PowerMH, a power sampling method for large language models. By prefetching future proposals in a tree of accept/reject decisions and using a predictive traversal rule, PreSTO maintains the same Metropolis–Hastings transition kernel while reducing model calls. Experiments on seven datasets and five base LLMs show median speedups of 1.71×, 1.91×, and 2.33× for PowerMH, EntropyCut, and MultiTryMH, respectively, with fewer and shorter model calls.

By Nan Jiang, Panagiotis Theodoropoulos, Wei Deng
arXiv Computation and Language
Oct 19

DominoTree: Conditional Tree-Structured Drafting with Domino for Speculative Decoding

DominoTree is a speculative decoding method that builds a conditional tree of draft tokens using Domino’s path‑dependent causal correction while restricting to the top‑M candidates. It achieves significant speedups over standard autoregressive decoding—averaging 5.33× on Qwen3‑4B and 6.89× on Qwen3‑8B at temperature zero—and outperforms both Domino and DDTree variants across a range of temperatures and batch sizes. The approach also improves accepted token length and maintains higher acceptance rates than chain‑based methods in various serving scenarios.

By Saw S. Lin (Zhiqi Zhang), Jyh-Shing Roger Jang
arXiv Machine Learning
Oct 9

JevForest: Path Voting for Budgeted Feature Acquisition

JevForest is a feature‑acquisition policy that aggregates path‑dependent proposals from bootstrapped trees, weights them by global training information gain, and uses a shared masked classifier to predict from the acquired values. In online experiments, a four‑question forest on AG News achieved 0.729 accuracy versus 0.667 for a static gain ranking and 0.583 for random ordering, while on TREC the ordering reversed. Offline MiniBooNE tests showed accuracies of 0.845 with ten features and 0.885 with forty features, indicating that Jev’s effectiveness varies with task, predictor, and budget constraints.

By Yu Yan
arXiv Computation and Language
Oct 1

OPTS-TTPO: Enhancing Finite-Sample Policy-Gradient Learning with Tree Search

arXiv:2609.40035v1 Announce Type: new Abstract: The policy-gradient theorem gives the exact gradient under the current policy, but finite on-policy samples may miss rare high-return trajectories. We...

By Junyu Lu, Shichao Weng, Zhiqiang Wang, Haojie Luo, Jingfan Zhang, Yuhua Zhou, Cheng Du, Yuzhuo Zhang, Xi Li, Jinwei Du, Tiancheng Feng, Chuan Xiao, Shuyuan Zheng
arXiv Computation and Language
Oct 15

TreeSpark: Learning to Draft the Trees You Verify for Speculative Decoding

TreeSpark is a new training and inference framework that extends the semi‑autoregressive DSpark architecture to improve speculative decoding. It builds parent‑conditioned candidate trees in a single backbone pass and then replays their expansion, pruning, and packing during training, using survival negative log‑likelihood and a capped coverage hinge to weight retained edges and promote target‑important alternatives. Evaluations on Qwen3‑4B and Qwen3‑8B across nine general benchmarks and six writing domains show that TreeSpark increases mean acceptance length by 23.4%–31.6% and mean single‑request throughput by 15.1%–25.0% compared to DSpark, with additional gains when using the proposed supervision. whyItMatters":"TreeSpark demonstrates that a unified training and inference approach can substantially boost both acceptance length and throughput in speculative decoding, offering measurable performance improvements for large language models."

By Jihao Zhao, Qianyu Jiang, Shuaishuai Zu, Pengfei Li, Guanghuan Fang, Ben Feng, Biao Qin, Zhibin Wang, Baochuan Yang