Events in April–May 2022
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Polaris-tt: Achile Baucher: le modèle World3 Polaris-tt: Achile Baucher: le modèle World3
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April 7, 2022 -
Polaris-tt: Rémi Castera - Statistical discrimination in Stable Matchings Polaris-tt: Rémi Castera - Statistical discrimination in Stable Matchings
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April 14, 2022 -
Polaris-tt: Victor Leger – A large dimensional analysis of multi-task semi-supervised classification Polaris-tt: Victor Leger – A large dimensional analysis of multi-task semi-supervised classification
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April 28, 2022Seminar by Martin Schreiber (LJK, Airsea) Seminar by Martin Schreiber (LJK, Airsea)
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April 28, 2022Title: A Brief Glimpse on Emerging Time Integration Methods for Weather and Climate Simulations
Speaker: Martin Schreiber
Abstract:
Weather and climate simulations face new challenges due to changes in computer architectures caused by physical limitations. From a pure computing perspective, algorithms are required to cope with stagnating or even decreasing per-core speed and increasing on-chip parallelism. These trends will continue and already led to research on partly disruptive mathematical and algorithmic reformulations of dynamic cores, e.g., using (additional) parallelism along the time dimension.
This presentation provides an overview and introduction of a variety of promising newly developed and evaluated time integration methods for equations related to prototypical dynamical cores, all aimed at improving the ratio of wall clock time vs. error: Rational Approximation of Exponential Integration (REXI), Parallel Full Approximation Scheme in Space and Time (PFASST) and Semi-Lagrangian methods combined with Parareal. We get improved time-vs.-error rates, but sometimes with additional challenges on the way which needs to be further overcome. Overall, our results motivate further investigation and combination of these methods for operational weather/climate systems.
I gratefully acknowledge collaborators related to this presentation
Jed Brown, Finn Capelle, François Hamon, Terry Haut, Richard Loft, Michael Minion, Matthew Normile, Nathanael Schaeffer, Andreas Schmitt, Pedro S. Peixoto, Raphael Schilling -
Polaris-tt: Hugo Lebeau – A random matrix analysis of kernel-based online learning: coping with limited memory resources Polaris-tt: Hugo Lebeau – A random matrix analysis of kernel-based online learning: coping with limited memory resources
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May 5, 2022Polaris-datamove Seminar: Jonatha Anselmi (Title: Recent advances in load balancing: replication, speculation and auto-scaling) Polaris-datamove Seminar: Jonatha Anselmi (Title: Recent advances in load balancing: replication, speculation and auto-scaling)
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May 5, 2022Title: Recent advances in load balancing: replication, speculation and auto-scalingAbstract: In this talk, we will discuss modern approaches for load balancing in large-scale parallel-server systems: replication, speculation and auto-scaling. Replication sends multiple copies of a given job, simultaneously upon its arrival, to multiple servers and then uses the results from whichever copy responds first. Speculation sends one or multiple copies of a given job only once the system smartly detects it as a "straggler", i.e., as a job taking longer than expected to complete because of some unfortunate runtime phenomenon. Auto-scaling allows the net service capacity, or overall number of servers, to scale up or down in response to the current load and within the same timescale of job dynamics. We will review the state of the art and present some recent results in the flavour of mean-field and fluid limit theorems.
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Workshop d'axe Workshop d'axe
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May 12, 2022 -
Polaris-tt: Henry-Joseph Audeoud (title to be annouced) Polaris-tt: Henry-Joseph Audeoud (title to be annouced)
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May 19, 2022