Now showing items 1-20 of 89

  • 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 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 ...
  • 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 ...
  • Álgebra lineal en la educación para el desarrollo sostenible 

    García Planas, María Isabel; Taberna Torres, Judit; Rina García, Natalia (Iniciativa Digital Politècnica, Oficina de Publicacions Acadèmiques Digitals de la UPC, 2018)
    Book
    Open Access
    El objetivo de este libro es desarrollar y trabajar, desde el álgebra lineal, aspectos vinculados al desarrollo sostenible, para sensibilizar sobre esta cuestión. Para ello, se han elaborado diversos proyectos, de dificultad ...
  • Álgebra lineal : teoría y práctica 

    Perelló, Miguel Ángel (Edicions UPC, 2002)
    Book
    Restricted access to UB, UAB, UPC, UPF, UdG, UdL, URV, UOC, BC, UVic, UJI, URL, UIC users
    El presente libro es sólo una parte del curso que con el mismo título se ofrece de forma gratutita en www.aprendes.com. Su único objetivo es presentar sus contenidos en formato pdf para que el estudiante pueda obtener una ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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 ...
  • 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 ...
  • Apuntes ACM 2019- Álgebra lineal y geometría 

    Carmona Mejías, Ángeles; Encinas Bachiller, Andrés Marcos (2019-02)
    External research report
    Open Access
  • 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 ...
  • Bounding the distance of a controllable and observable system to an uncontrollable or unobservable one 

    Clotet Juan, Josep; García Planas, María Isabel (1999)
    Article
    Open Access
    Let $(A,B,C)$ be a triple of matrices representing a time-invariant linear system $\left .\aligned \dot x(t)&=Ax(t)+Bu(t)\\y(t)&=Cx(t)\endaligned \right \}$ under similarity equivalence, corresponding to a realization ...
  • Bounding the distance of a controllable system to an uncontrollable one 

    Clotet Juan, Josep; García Planas, María Isabel (1998)
    Article
    Open Access
    Let $(A,B)$ be a pair of matrices representing a time-invariant linear system $\dot x(t)=Ax(t)+Bu(t)$ under block-similarity equivalence. In this paper we measure the distance between a controllable pair of matrices ...