1 code implementation • 13 Jul 2022 • Paolo Boldi, Flavio Furia, Sebastiano Vigna
In this paper, we study the problem of score and rank monotonicity for classical centrality measures in the case of undirected networks: in this case, we require that score, or relative importance, improve at both endpoints of the new edge.
no code implementations • 2 Feb 2022 • Paolo Boldi, Flavio Furia, Sebastiano Vigna
We show that, surprisingly, the situation is very different for undirected graphs, and in particular that PageRank is neither score nor rank monotone.
2 code implementations • 3 May 2018 • David Blackman, Sebastiano Vigna
Then, we describe some scramblers, that is, nonlinear functions applied to the state array that reduce or delete the linear artifacts, and propose combinations of linear transformations and scramblers that give extremely fast pseudorandom number generators of high quality.
Data Structures and Algorithms Cryptography and Security Mathematical Software
1 code implementation • 2 Dec 2013 • Djamal Belazzougui, Paolo Boldi, Giuseppe Ottaviano, Rossano Venturini, Sebastiano Vigna
The computation of a peeling order in a randomly generated hypergraph is the most time-consuming step in a number of constructions, such as perfect hashing schemes, random $r$-SAT solvers, error-correcting codes, and approximate set encodings.
Data Structures and Algorithms
1 code implementation • 19 Jun 2012 • Sebastiano Vigna
Compressed inverted indices in use today are based on the idea of gap compression: documents pointers are stored in increasing order, and the gaps between successive document pointers are stored using suitable codes which represent smaller gaps using less bits.
no code implementations • 19 Nov 2011 • Lars Backstrom, Paolo Boldi, Marco Rosa, Johan Ugander, Sebastiano Vigna
It is not completely clear whether the selected individual is part of the five, so this could actually allude to distance five or six in the language of graph theory, but the "six degrees of separation" phrase stuck after John Guare's 1990 eponymous play.
Social and Information Networks Physics and Society
no code implementations • 25 Nov 2010 • Paolo Boldi, Marco Rosa, Sebastiano Vigna
Recently, the ANF algorithm (approximate neighbourhood function) has been proposed with the purpose of approximating NG(t) on large graphs.
Data Structures and Algorithms Social and Information Networks Physics and Society
1 code implementation • 1 Dec 2009 • Sebastiano Vigna
We sketch the history of spectral ranking, a general umbrella name for techniques that apply the theory of linear maps (in particular, eigenvalues and eigenvectors) to matrices that do not represent geometric transformations, but rather some kind of relationship between entities.