edu.ucar.opensky::technotes:549 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-26T02:28:20.932044 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7z89fpb Accelerating CMIP data analysis with parallel computing in R 2017-06-30T00:00:00Z publication https://n2t.org/ark:/85065/d7z89fpb https://doi.org/10.5065/D61V5CP8 Milroy, Daniel author Chen, Sophia author Vanderwende, Brian author Hammerling, Dorit author UCAR/NCAR - Library publisher In this Technical Note we examine eight schemes for parallelizing Extreme Value Analysis (EVA) on Coupled Model Intercomparison Project data via R foreach, doParallel, and doMPI packages. We perform strong scaling studies to delineate the performance impacts of factors such as R cluster type (TCP/IP sockets and MPI), communication protocol (Ethernet, IP over InfiniBand, and MPI), loop parallelization (outer or inner loop), and approaches to reading data from the NCAR GLADE parallel filesystem. We elucidate peculiarities of R memory management and overhead associated with interprocess communication and discuss broadcast limitations of Rmpi. The best performing scheme parallelizes the outer EVA loop across latitude and reads only the subset of the data operated on in the inner loop over longitude; the different cluster types and communication protocols all perform about equally for this scheme. This configuration represents a parallel speedup of 50 with 96 R workers, and is scalable for EVA on larger problem sizes than those presented here. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Coupled climate models Statistical applications theme U.S. National Aeronautics and Space Administration Global Change Master Directory GCMD 2021-09-17 revision 11.2 NASA Global Change Master Directory originator Valids List: Science and Services Keywords Copyright Author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation