Searcharxiv⌕ Search

arXiv subjects

Leo Liberti

Publications and source records attributed to Leo Liberti.

41 records · Page 3Linked to original sources
arXiv2007

Fast paths in large-scale dynamic road networks

Efficiently computing fast paths in large scale dynamic road networks (where dynamic traffic information is known over a part of the network) is a practical problem faced by several traffic information service providers who wish to offer a realistic fast path computation to GPS terminal enabled vehicles. The heuristic solution method we propose is based on a highway hierarchy-based shortest path algorithm for static large-scale networks; we maintain a static highway hierarchy and perform each query on the dynamically evaluated network.

cs.NI↗
arXiv2006

The Discretizable Molecular Distance Geometry Problem

Given a weighted undirected graph $G=(V,E,d)$, the Molecular Distance Geometry Problem (MDGP) is that of finding a function $x:G\to \mathbb{R}^{3}$, where $||x(u)-x(v)||=d(u,v)$ for each $\{u,v\}\in E$. We show that under a few assumptions usually satisfied in proteins, the MDGP can be formulated as a search in a discrete space. We call this MDGP subclass the Discretizable MDGP (DMDGP). We show that the DMDGP is \textbf{NP}-complete and we propose an algorithm, called Branch-and-Prune (BP), which solves the DMDGP exactly. The BP algorithm performs exceptionally well in terms of solution accuracy and can find all solutions to any DMDGP instance. We successfully test the BP algorithm on several randomly generated instances.

q-bio.BM↗
arXiv2003

A Theorem on Prime Numbers

The theorem presented in this paper allows the creation of large prime numbers (of order up to o(n^2)) given a table of all primes up to n.

math.GM↗
arXiv2002

Performance Comparison of Function Evaluation Methods

We perform a comparison of the performance and efficiency of four different function evaluation methods: black-box functions, binary trees, $n$-ary trees and string parsing. The test consists in evaluating 8 different functions of two variables $x,y$ over 5000 floating point values of the pair $(x,y)$. The outcome of the test indicates that the $n$-ary tree representation of algebraic expressions is the fastest method, closely followed by black-box function method, then by binary trees and lastly by string parsing.

cs.SC↗