• openAccess   3D high definition video coding on a GPU-based heterogeneous system 

      Rodríguez Sánchez, Rafael; Martínez, José Luis; De Cock, Jan; Fernández Escribano, Gerardo; Pieters, Bart; Sánchez, José L.; Claver, José M.; Van de Walle, Rik Elsevier (2013-11)
      H.264/MVC is a standard for supporting the sensation of 3D, based on coding from 2 (stereo) to N views. H.264/MVC adopts many coding options inherited from single view H.264/AVC, and thus its complexity is even higher, ...
    • openAccess   A Case for Malleable Thread-Level Linear Algebra Libraries: The LU Factorization With Partial Pivoting 

      Catalán, Sandra; Herrero Zaragoza, José R.; Quintana-Orti, Enrique S.; Rodríguez Sánchez, Rafael; Van de Geijn, Robert A. IEEE (2019-01)
      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 ...
    • openAccess   Adapting hierarchical bidirectional inter prediction on a GPU-based platform for 2D and 3D H.264 video coding 

      Rodríguez Sánchez, Rafael; Martínez, José Luis; De Cock, Jan; Fernández Escribano, Gerardo; Pieters, Bart; Sánchez, José L.; Claver, José M.; Van de Walle, Rik SpringerOpen (2013)
      The H.264/AVC video coding standard introduces some improved tools in order to increase compression efficiency. Moreover, the multi-view extension of H.264/AVC, called H.264/MVC, adopts many of them. Among the new features, ...
    • openAccess   Architecture-Aware Con guration and Scheduling of Matrix Multiplication on Asymmetric Multicore Processors 

      Catalán, Sandra; Igual, Francisco D.; Mayo, Rafael; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Springer US (2016-09)
      Asymmetric multicore processors (AMPs) have recently emerged as an appealing technology for severely energy-constrained environments, especially in mobile appliances where heterogeneity in applications is mainstream. ...
    • closedAccess   Arquitecture-aware optimization of an hevc decoder on asymmetric multicore processors 

      Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Springer Verlag (2016-05)
      Low-power asymmetric multicore processors (AMPs) have attracted considerable attention due to their appealing performance/power ratio for energy-constrained environments. However, these processors pose a significant ...
    • closedAccess   Energy Balance between Voltage-Frequency Scaling and Resilience for Linear Algebra Routines on Low-Power Multicore Architectures 

      Catalán, Sandra; Herrero, José R.; Quintana-Orti, Enrique S.; Rodríguez Sánchez, Rafael Elsevier (2018)
      Near Threshold Voltage (NTV) computing has been recently proposed as a technique to save energy, at the cost of incurring higher error rates including, among others, Silent Data Corruption (SDC). In this paper, we evaluate ...
    • openAccess   Energy Balance between Voltage-Frequency Scaling and Resilience for Linear Algebra Routines on Low-Power Multicore Architectures 

      Catalán, Sandra; Herrero Zaragoza, José R.; Quintana-Orti, Enrique S.; Rodríguez Sánchez, Rafael Elsevier (2017)
      Near Threshold Voltage (NTV) computing has been recently proposed as a technique to save energy, at the cost of incurring higher error rates including, among others, Silent Data Corruption (SDC). In this paper, we evaluate ...
    • closedAccess   Fast video transcoding from HEVC to VP9 

      De la Torre, Enrique; Rodríguez Sánchez, Rafael; Martínez, José Luis Institute of Electrical and Electronics Engineers (2015-10)
      HEVC and VP9 are the current state-of-the-art in video compression, since their bit-streams were recently finalized in January and May 2013, respectively. These codecs are the generational successors of the currently most ...
    • closedAccess   H.264/AVC inter prediction for heterogeneous computing systems 

      Rodríguez Sánchez, Rafael; Martínez, José Luis; Fernández Escribano, Gerardo; Claver, José M.; Sánchez, José L. Springer (2013)
      H.264/AVC is the latest standard for video compression and is a significant advance, but at the expense of increasing computing needs. Recently, the progress of GPUs has attracted considerable attention because they are ...
    • openAccess   H.264/AVC inter prediction on accelerator-based multi-core systems 

      Rodríguez Sánchez, Rafael; Martínez, José Luis; Fernández Escribano, Gerardo; Sánchez, José L.; Claver, José M. Springer (2013)
      The AVC video coding standard adopts variable block sizes for inter frame coding to increase compression efficiency, among other new features. As a consequence of this, an AVC encoder has to employ a complex mode decision ...
    • openAccess   Look-ahead in the two-sided reduction to compact band forms for symmetric eigenvalue problems and the SVD 

      Rodríguez Sánchez, Rafael; Catalán, Sandra; Herrero, José R.; Quintana-Orti, Enrique S.; Tomás Domínguez, Andrés Enrique Springer Verlag (2019)
      We address the reduction to compact band forms, via unitary similarity transformations, for the solution of symmetric eigenvalue problems and the computation of the singular value decomposition (SVD). Concretely, in the ...
    • closedAccess   Multi-threaded dense linear algebra libraries for low-power asymmetric multicore processors 

      Catalán, Sandra; Herrero Zaragoza, José R.; Igual, Francisco D.; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S.; Adeniyi-Jones, Chris Elsevier (2018-03)
      Dense linear algebra libraries, such as BLAS and LAPACK, provide a relevant collection of numerical tools for many scientific and engineering applications. While there exist high performance implementations of the BLAS ...
    • closedAccess   Multimedia Communications Using a Fast and Flexible DVC to H.264/AVC/SVC Transcoder 

      Corrales García, Alberto; Rodríguez Sánchez, Rafael; Martínez, José Luis; Fernández Escribano, Gerardo; Quiles, Francisco José Springer (2013)
      The evolution of network technologies and mobile devices (equipped with low-cost video cameras) offer new multimedia services for mobile telephony, such as video communications. However, this kind of multimedia services ...
    • openAccess   Programming parallel dense matrix factorizations with look-ahead and OpenMP 

      Catalán, Sandra; Castelló, Adrián; Igual, Francisco D.; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Springer (2019)
      We investigate a parallelization strategy for dense matrix factorization (DMF) algorithms, using OpenMP, that departs from the legacy (or conventional) solution, which simply extracts concurrency from a multi-threaded ...
    • openAccess   Revisiting conventional task schedulers to exploit asymmetry in multi-core architectures for dense linear algebra operations 

      Costero, Luis; Igual, Francisco D.; Olcoz, Katzalin; Catalán, Sandra; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Elsevier (2017)
      Dealing with asymmetry in the architecture opens a plethora of questions related with the performance- and energy-efficient scheduling of task-parallel applications. While there exist early attempts to tackle this problem, ...
    • closedAccess   Static scheduling of the LU factorization with look-ahead on asymmetric multicore processors 

      Catalán, Sandra; Herrero, José R.; Quintana-Orti, Enrique S.; Rodríguez Sánchez, Rafael Elsevier (2018)
      We analyze the benefits of look-ahead in the parallel execution of the LU factorization with partial pivoting (LUpp) in two distinct “asymmetric” multicore scenarios. The first one corresponds to an actual hardware-asymmetric ...
    • closedAccess   Time and energy modeling of a high-performance multi-threaded Cholesky factorization 

      Catalán, Sandra; Igual, Francisco D.; Mayo, Rafael; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Springer (2016-02-05)
      We present accurate time and energy piece-wise models of high-performance multi-threaded implementations for the general matrix multiplication, triangular system solve with multiple right-hand sides, and symmetric rank-k ...
    • closedAccess   Time and energy modeling of high–performance Level-3 BLAS on x86 architectures 

      Alonso-Jordá, Pedro; Catalán, Sandra; Igual, Francisco D.; Mayo, Rafael; Rodríguez Sánchez, Rafael; Quintana-Orti, Enrique S. Elsevier (2015-06)
      We present accurate piece-wise models for the time and energy costs of high performance implementations of both the matrix multiplication (gemm) and the triangular system solve with multiple right-hand sides (trsm) on x86 ...
    • closedAccess   Two-sided orthogonal reductions to condensed forms on asymmetric multicore processors 

      Alonso-Jordá, Pedro; Catalán, Sandra; Herrero, José R.; Quintana-Orti, Enrique S.; Rodríguez Sánchez, Rafael Elsevier (2018)
      We investigate how to leverage the heterogeneous resources of an Asymmetric Multicore Processor (AMP) in order to deliver high performance in the reduction to condensed forms for the solution of dense eigenvalue and ...