244 research outputs found
Quadrature Points via Heat Kernel Repulsion
We discuss the classical problem of how to pick weighted points on a
dimensional manifold so as to obtain a reasonable quadrature rule
This problem, naturally, has a long history; the purpose of our paper is to
propose selecting points and weights so as to minimize the energy functional
\sum_{i,j =1}^{N}{ a_i a_j \exp\left(-\frac{d(x_i,x_j)^2}{4t}\right) }
\rightarrow \min, \quad \mbox{where}~t \sim N^{-2/d}, is the
geodesic distance and is the dimension of the manifold. This yields point
sets that are theoretically guaranteed, via spectral theoretic properties of
the Laplacian , to have good properties. One nice aspect is that the
energy functional is universal and independent of the underlying manifold; we
show several numerical examples
A generalization of short-period Tausworthe generators and its application to Markov chain quasi-Monte Carlo
A one-dimensional sequence is said to be
completely uniformly distributed (CUD) if overlapping -blocks , , are uniformly distributed
for every dimension . This concept naturally arises in Markov chain
quasi-Monte Carlo (QMC). However, the definition of CUD sequences is not
constructive, and thus there remains the problem of how to implement the Markov
chain QMC algorithm in practice. Harase (2021) focused on the -value, which
is a measure of uniformity widely used in the study of QMC, and implemented
short-period Tausworthe generators (i.e., linear feedback shift register
generators) over the two-element field that approximate CUD
sequences by running for the entire period. In this paper, we generalize a
search algorithm over to that over arbitrary finite fields
with elements and conduct a search for Tausworthe generators
over with -values zero (i.e., optimal) for dimension
and small for , especially in the case where , and . We
provide a parameter table of Tausworthe generators over , and
report a comparison between our new generators over and existing
generators over in numerical examples using Markov chain QMC
From van der Corput to modern constructions of sequences for quasi-Monte Carlo rules
In 1935 J.G. van der Corput introduced a sequence which has excellent uniform
distribution properties modulo 1. This sequence is based on a very simple
digital construction scheme with respect to the binary digit expansion.
Nowadays the van der Corput sequence, as it was named later, is the prototype
of many uniformly distributed sequences, also in the multi-dimensional case.
Such sequences are required as sample nodes in quasi-Monte Carlo algorithms,
which are deterministic variants of Monte Carlo rules for numerical
integration. Since its introduction many people have studied the van der Corput
sequence and generalizations thereof. This led to a huge number of results.
On the occasion of the 125th birthday of J.G. van der Corput we survey many
interesting results on van der Corput sequences and their generalizations. In
this way we move from van der Corput's ideas to the most modern constructions
of sequences for quasi-Monte Carlo rules, such as, e.g., generalized Halton
sequences or Niederreiter's -sequences
Applications of the Galois Model LFSR in Cryptography
The linear feedback shift-register is a widely used tool for generating cryptographic sequences. The properties of the Galois model discussed here offer many opportunities to improve the implementations that already exist. We explore the overall properties of the phases of the Galois model and conjecture a relation with modular Golomb rulers. This conjecture points to an efficient method for constructing non-linear filtering generators which fulfil Golic s design criteria in order to maximise protection against his inversion attack. We also produce a number of methods which can improve the rate of output of sequences by combining particular distinct phases of smaller elementary sequences
Some Results on the Complexity of Numerical Integration
This is a survey (21 pages, 124 references) written for the MCQMC 2014
conference in Leuven, April 2014. We start with the seminal paper of Bakhvalov
(1959) and end with new results on the curse of dimension and on the complexity
of oscillatory integrals. Some small errors of earlier versions are corrected
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