,
Igor Shinkar
,
Emanuele Viola
,
Renfei Zhou
Creative Commons Attribution 4.0 International license
We obtain several results on sampling product distributions in a local and randomness-efficient fashion: 1) Let D = (D_1,D_2,…,D_n) be a product distribution where the D_i have constant support and have dyadic probability masses (i.e., of the form a/2^b where a,b are integers). Then D can be sampled in constant time in the bit-probe model (equivalently, in NC⁰) and randomness complexity (h(D)+ε)n, up to an exponentially small statistical error. The dyadic requirement is necessary. 2) Every p-biased distribution can be sampled in constant time in the cell-probe model with randomness complexity h(p)n + √n ⋅ polylog(n), up to a polynomially small statistical distance. 3) We determine the tradeoffs between locality and statistical distance for sampling the 1/4-biased distribution using non-trivial randomness complexity (e.g., 1.99n). For 2 bit probes, essentially no non-trivial approximation is possible; for 3 bit probes, we give a sampler with 1/poly(n) statistical distance and show that this is best possible; finally, 4 bit probes suffice for exponentially small distance. Our constructions rely on pseudorandom distributions that are bounded uniform on average. These distributions are obtained using various tools from low-density parity-check codes, and recent results on succinct and retrieval data structures by Hu, Liang, Yu, Zhang, and Zhou (STOC 2025).
@InProceedings{horacsek_et_al:LIPIcs.ICALP.2026.109,
author = {Horacsek, Jordan and Lee, Chin Ho and Shinkar, Igor and Viola, Emanuele and Zhou, Renfei},
title = {{Local Samplers for Product Distributions}},
booktitle = {53rd International Colloquium on Automata, Languages, and Programming (ICALP 2026)},
pages = {109:1--109:23},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-428-4},
ISSN = {1868-8969},
year = {2026},
volume = {374},
editor = {Bhattacharya, Sayan and Nanongkai, Danupon and Benedikt, Michael and Puppis, Gabriele},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2026.109},
URN = {urn:nbn:de:0030-drops-264981},
doi = {10.4230/LIPIcs.ICALP.2026.109},
annote = {Keywords: Sampling, Succinct data structures, Pseudorandomness}
}