No. 12 (00081) Family name : Tkachov Given name : Fyodor Affiliation : Institute for Nuclear Research of RAS Abbreviation : INR RAS E-mail address : ftkachov@ms2.inr.ac.ru Title : POUZYRY: a new class of algorithms for modelling a function from a random sample Authors : F.V.Tkachov Abstract : Reexamined are mathematical foundations of the fundamental problem of modelling a function from a random sample, which has two important applications: multi-dimensional adaptive MC integration and construction of quasi-optimal observables (hep-ph/0001019) for data analysis. The concept of week convergence, although largely ignored beyond abstract mathematics, is central for a systematic exploration of algorithmic solutions for the problem, and is the basis of POUZYRY, a novel class of algorithms which has a considerable flexibility of implementation including: iterative schemes; applicability to non-positive functions; a relatively small number of random points required; a weak sensitivity to the dimensionality of the function's domain of definition; insensitivity to the choice of coordinate axes. POUZYRY is ideologically related to, and borrows some algorithmic solutions (without which it would be prohibitively slow) from, the Optimal Jet Finder (hep-ph/0301185), which also exploits the concept of weak convergence; this relation explains why POUZYRY can locate peaks of a distribution with a relative ease. A simple exploratory implementation of POUZYRY written in Oberon/Component Pascal is compared with VEGAS on some simple tests.