M. Cotallo

Publications (4)7.37 Total impact

• Article: Nonequilibrium spin-glass dynamics from picoseconds to a tenth of a second.

  F Belletti, M Cotallo, A Cruz, L A Fernandez, A Gordillo-Guerrero, M Guidetti, A Maiorano, F Mantovani, E Marinari, V Martin-Mayor, [......], D Navarro, G Parisi, S Perez-Gaviro, J J Ruiz-Lorenzo, S F Schifano, D Sciretti, A Tarancon, R Tripiccione, J L Velasco, D Yllanes
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  ABSTRACT: We study numerically the nonequilibrium dynamics of the Ising spin glass, for a time spanning 11 orders of magnitude, thus approaching the experimentally relevant scale (i.e., seconds). We introduce novel analysis techniques to compute the coherence length in a model-independent way. We present strong evidence for a replicon correlator and for overlap equivalence. The emerging picture is compatible with noncoarsening behavior.
  Physical Review Letters 11/2008; 101(15):157201. · 7.37 Impact Factor
• Source

  Available from: ArXiv

  Article: Nonequilibrium spin glass dynamics from picoseconds to 0.1 seconds

  F. Belletti, M. Cotallo, A Cruz, L. A. Fernandez, A. Gordillo-Guerrero, M. Guidetti, A. Maiorano, F. Mantovani, E. Marinari, V. Martin-Mayor, [......], D. Navarro, G. Parisi, S. Perez-Gaviro, J. J. Ruiz-Lorenzo, S. F. Schifano, D. Sciretti, A. Tarancon, R. Tripiccione, J. L. Velasco, D. Yllanes
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  ABSTRACT: We study numerically the nonequilibrium dynamics of the Ising Spin Glass, for a time that spans eleven orders of magnitude, thus approaching the experimentally relevant scale (i.e. {\em seconds}). We introduce novel analysis techniques that allow to compute the coherence length in a model-independent way. Besides, we present strong evidence for a replicon correlator and for overlap equivalence. The emerging picture is compatible with non-coarsening behavior.
  05/2008;
• Source

  Available from: ArXiv

  Article: JANUS: an FPGA-based System for High Performance Scientific Computing

  F. Belletti, M. Cotallo, A Cruz, L. A. Fernández, A. Gordillo, M. Guidetti, A. Maiorano, F. Mantovani, E. Marinari, V. Martín-Mayor, [......], D. Navarro, G. Parisi, S. Pérez-Gaviro, M Rossi, J. J. Ruiz-Lorenzo, S. F. Schifano, D. Sciretti, A. Tarancón, R. Tripiccione, J. L. Velasco
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  ABSTRACT: This paper describes JANUS, a modular massively parallel and reconfigurable FPGA-based computing system. Each JANUS module has a computational core and a host. The computational core is a 4x4 array of FPGA-based processing elements with nearest-neighbor data links. Processors are also directly connected to an I/O node attached to the JANUS host, a conventional PC. JANUS is tailored for, but not limited to, the requirements of a class of hard scientific applications characterized by regular code structure, unconventional data manipulation instructions and not too large data-base size. We discuss the architecture of this configurable machine, and focus on its use on Monte Carlo simulations of statistical mechanics. On this class of application JANUS achieves impressive performances: in some cases one JANUS processing element outperfoms high-end PCs by a factor ~ 1000. We also discuss the role of JANUS on other classes of scientific applications.
  11/2007;
• Source

  Available from: ArXiv

  Article: Simulating spin systems on IANUS, an FPGA-based computer

  F. Belletti, M. Cotallo, A. Cruz, L.A. Fernández, A. Gordillo, A. Maiorano, F. Mantovani, E. Marinari, V. Martín-Mayor, A. Muñoz-Sudupe, D. Navarro, S. Pérez-Gaviro, J.J. Ruiz-Lorenzo, S.F. Schifano, D. Sciretti, A. Tarancón, R. Tripiccione, J.L. Velasco
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  ABSTRACT: We describe the hardwired implementation of algorithms for Monte Carlo simulations of a large class of spin models. We have implemented these algorithms as VHDL codes and we have mapped them onto a dedicated processor based on a large FPGA device. The measured performance on one such processor is comparable to O(100) carefully programmed high-end PCs: it turns out to be even better for some selected spin models. We describe here codes that we are currently executing on the IANUS massively parallel FPGA-based system.
  Computer Physics Communications. 04/2007;