Now showing items 1-20 of 108

    • A case for malleable thread-level linear algebra libraries: The LU factorization with partial pivoting 

      Catalán Pallarés, Sandra; Herrero Zaragoza, José Ramón; Quintana Ortí, Enrique Salvador; Rodríguez Sánchez, Rafael; Van De Geijn, Robert (Institute of Electrical and Electronics Engineers (IEEE), 2019-01-31)
      Article
      Open Access
      We propose two novel techniques for overcoming load-imbalance encountered when implementing so-called look-ahead mechanisms in relevant dense matrix factorizations for the solution of linear systems. Both techniques target ...
    • A cross-layer review of deep learning frameworks to ease their optimization and reuse 

      Tabani, Hamid; Pujol Torramorell, Roger; Abella Ferrer, Jaume; Cazorla Almeida, Francisco Javier (Institute of Electrical and Electronics Engineers (IEEE), 2020)
      Conference report
      Open Access
      Machine learning and especially Deep Learning (DL) approaches are at the heart of many domains, from computer vision and speech processing to predicting trajectories in autonomous driving and data science. Those approaches ...
    • A general method to obtain the spectrum and local spectra of a graph from its regular partitions 

      Dalfó Simó, Cristina; Fiol Mora, Miquel Àngel (2020-07-12)
      Article
      Open Access
      It is well known that, in general, part of the spectrum of a graph can be obtained from the adjacency matrix of its quotient graph given by a regular partition. In this paper, a method that gives all the spectrum, and also ...
    • A geometric approach to the Carlson problem 

      Compta Creus, Albert; Ferrer Llop, Josep (Society for Industrial and Applied Mathematics (Filadèlfia), 2000)
      Article
      Open Access
      The possible observability indices of an observable pair of matrices, when supplementary subpairs are prescribed, are characterized when the “quotient” one is nilpotent. The geometric techniques used are also valid in the ...
    • A matrix derivation of a representation theorem for (trAp)1/p 

      Neudecker, Heinz (Universitat Politècnica de Catalunya. Centre de Càlcul, 1989)
      Article
      Open Access
      A matrix derivation of a well-known representation theorem for (tr Ap)1/p is given, which is the solution of a restricted maximization problem. The paper further gives a solution of the corresponding restricted minimization ...
    • A matrix function useful in the estimation of linear continuous-time models. 

      Neudecker, Heinz (Institut d'Estadística de Catalunya, 2006)
      Article
      Open Access
      In a recent publication Chen & Zadrozny (2001) derive some equations for efficiently computing eA and ∇ eA, its derivative. They employ an expression due to Bellman (1960), Snider (1964) and Wilcox (1967) for the differential ...
    • A new proof of the Milliken-Akdeniz theorem 

      Neudecker, Heinz (Universitat Politècnica de Catalunya. Centre de Càlcul, 1989)
      Article
      Open Access
      A simple proof is given for a theorem by Milliken and Akdeniz (1977) about the difference of the Moore-Penrose inverses of two positive semi-definite matrices.
    • A note on symplectic and Poisson linearization of semisimple Lie algebra actions 

      Miranda Galcerán, Eva (2015-03)
      External research report
      Open Access
      In this note we prove that an analytic symplectic action of a semisimple Lie algebra can be locally linearized in Darboux coordinates. This result yields simultaneous analytic linearization for Hamiltonian vector fields ...
    • A recursion formula for expected negative and positive powers of the central Wishart distribution 

      Neudecker, Heinz (Institut d'Estadística de Catalunya, 2007)
      Article
      Open Access
      We use Haff’s fundamental identity to express the expectation of Sp in lower-order terms, where S follows the central Wishart distribution.
    • A simple proof of the spectral excess theorem for distance-regular graphs 

      Fiol Mora, Miquel Àngel; Gago Álvarez, Silvia; Garriga Valle, Ernest (Elsevier, 2010-04-15)
      Article
      Restricted access - publisher's policy
      The spectral excess theorem provides a quasi-spectral characterization for a (regular) graph Γ with d+1 distinct eigenvalues to be distance-regular graph, in terms of the excess (number of vertices at distance d) of each ...
    • Algebra lineal 

      Boadas Elvira, Juan (Edicions UPC, 2002)
      Book
      Restricted access to UB, UAB, UPC, UPF, UdG, UdL, URV, UOC, BC, UVic, UJI, URL, UIC users
      Aquest text aborda els temes fonamentals de l'Àlgebra Lineal que formen part dels continguts de primer curs de les carreres d'Enginyeria i Ciències: aplicacions lineals, matrius, determinants, diagonalització, producte ...
    • Aligning modeled and observed behavior: A compromise between computation complexity and quality 

      Dongen, Boudewijn F. van; Carmona Vargas, Josep; Chatain, Thomas; Taymouri, Farbod (Springer, 2017)
      Conference report
      Open Access
      Certifying that a process model is aligned with the real process executions is perhaps the most desired feature a process model may have: aligned process models are crucial for organizations, since strategic decisions can ...
    • An alternative collection of structural invariants for matrix pencils under strict equivalence 

      Díaz, Adolfo; García Planas, María Isabel (WSEAS Press. World Scientific and Engineering Academy and Society, 2009)
      Article
      Restricted access - publisher's policy
      We consider pairs of matrices (E;A), representing singular linear time invariant sys- tems in the form Ex_ (t) = Ax with E;A 2 Mp£n(C) under restricted equivalence. In this paper we obtain an alternative collection of ...
    • An alternative complete system of invariants for matrix pencils under strict equivalence 

      García Planas, María Isabel; Díaz, Adolfo (WSEAS Press. World Scientific and Engineering Academy and Society, 2009-12)
      Part of book or chapter of book
      Restricted access - publisher's policy
      We consider triples of matrices (E; A;B), representing singular linear time invariant systems in the form Ex_ (t) = Ax(t) + Bu(t), with E;A 2 Mp£n(C) and B 2 Mn£m(C), un- der proportional and derivative feedback. Using ...
    • An Eigenvector pattern arising in non linear regression 

      Cuadras, C.M. (Carlos Maria) (Universitat Politècnica de Catalunya. Centre de Càlcul, 1990)
      Article
      Open Access
      Let A = (aij) be an n x n matrix defined by aij = aji = i, i = 1,...,n. This paper gives some elementary properties of A and other related matrices. The eigenstructure of A is conjectured: given an eigenvector v of A the ...
    • Analizing exact controllability of l-order linear systems 

      García Planas, María Isabel (WSEAS Press, 2017-01-01)
      Article
      Open Access
      In recent years there has been growing interest in the descriptive analysis of l-order time invariant linear dynamical system xl = Al-1xl-1 ++ A0x0 where Ai are square complex matrices and xi denotes the i-th derivative ...
    • Analyzing control properties of multiagent linear systems 

      García Planas, María Isabel (2020-09-30)
      Article
      Open Access
      The networked multi-agent systems that they are interconnected via communication channels have great applicability in multiple areas, such as power grids, bioinformatics, sensor networks, vehicles, robotics and neuroscience, ...
    • Aplicacions lineals, diagonalització i vectors propis. Contextualització i objectius per a la ciència de dades 

      Pozo Montero, Francesc; Ripoll Missé, Jordi (Fundació per a la Universitat Oberta de Catalunya, 2019-02)
      Part of book or chapter of book
      Restricted access - publisher's policy
    • Aplicacions lineals, diagonalització i vectors propis. Problemes per a la ciència de dades 

      Pozo Montero, Francesc; Ripoll Missé, Jordi (Fundació per a la Universitat Oberta de Catalunya, 2019-02)
      Part of book or chapter of book
      Restricted access - publisher's policy
    • Application of the multilevel decomposition algorithm to the frequency analysis of large microstrip antenna arrays 

      Parrón Granados, Josep; Rius Casals, Juan Manuel; Mosig, Juan R. (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2002-03-31)
      Article
      Open Access
      The application of integral equation methods based in the method of moments discretization to solve large antenna arrays is difficult due to the fact that the computational requirements increase rapidly with the number ...