AI & ML
KL Before and After Mixing: A Round-Complexity Separation in Parallel Sampling
arXiv math.IT0 views
arXiv:2610.13924v1 Announce Type: cross Abstract: A parallel sampler can choose at random which coordinates to generate together. For a target $p$ and the output law $q_U$ of a schedule $U$ drawn afresh for each output, we compare the schedule-averaged divergence $\mathbb{E}_U D_{\mathrm{KL}}(p\|q_U)$ with the output-law divergence $D_{\mathrm{KL}}(p\|\mathbb{E}_U q_U)$, in nats. Rounds commit independent draws from exact conditional marginals frozen at the round's start, each output's schedule is drawn before sampling from a finite mixture of schedules, and every scheduled round is charged. For the uniform distribution on binary strings of even length $n$ with $n/2$ ones, the least expected number of rounds at a fixed tolerance $\varepsilon>0$ is $\Theta_\varepsilon((\log n)^2)$ under the first criterion but $(e^{-\varepsilon}+o(1))\log_2\ln n$ under the second, and the double-logarithmic order is attainable with the same round count on every run. For this target, a count-state recursion gives the exact least output divergence at every round cap over all causal randomized policies. The separation extends to weighted fixed-count targets with bounded weight ratios and quota fractions bounded away from zero and one, without permutation symmetry, and to the full-support Beta$(1,1)$--Bernoulli target, where the sharp expected cost under the output-law criterion is $(e^{-\varepsilon}/2+o(1))\log_2\log_2n$, attained with rare $n$-round runs. Prior work implies the order of the schedule-averaged cost on the balanced target and its $O_\varepsilon((\log n)^2)$ upper bounds on both extensions.
Source:https://arxiv.org/abs/2610.13924PreviousGPU-Based Parallel BP Decoding for Quantum LDPC MemoryNextTowards a Measure Theory of Semantic Information
Related posts

Email: OpenAI plans to merge ChatGPT's Chat and Work tabs on desktop, rolling out to select users before a wider release; Codex remains a separate experience (Ivan Mehta/TechCrunch)
0Techmeme

Memo: Alphabet is issuing €6B in euro-denominated debt across seven tranches, attracting €17B+ of demand; the company sold €9B of bonds earlier in 2026 (Reuters)
0Techmeme

S-1: Anthropic reports Q3 revenue up 12x YoY to nearly $17B, a net loss of $23.3B, up from $12.1B in Q3 2025, and operating expenses up 292% to $17.5B (Bailey Lipschultz/Bloomberg)
0Techmeme

Sources: Apple is developing a tabletop robot with a 9" screen and a swiveling arm, set for release in 2027 or 2028 for ~$1,000, as John Ternus pushes robotics (Aaron Tilley/The Information)
0Techmeme
Shutting the Door on the XCPE Botnet (Threat Intelligence)
0LWN.net

Canva Brings Free All-in-One Affinity App to iPad
0MacRumors