{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,1]],"date-time":"2026-05-01T23:03:27Z","timestamp":1777676607028,"version":"3.51.4"},"reference-count":15,"publisher":"SAGE Publications","issue":"4","license":[{"start":{"date-parts":[[2016,7,27]],"date-time":"2016-07-27T00:00:00Z","timestamp":1469577600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.sagepub.com\/page\/policies\/text-and-data-mining-license"}],"content-domain":{"domain":["journals.sagepub.com"],"crossmark-restriction":true},"short-container-title":["The International Journal of High Performance Computing Applications"],"published-print":{"date-parts":[[2016,11]]},"abstract":"<jats:p>This article presents a case study on the extension of parallel algorithms in tsunami and earthquake-cycle simulators for massively parallel execution on the K computer. We use two target applications: a tsunami-simulation program, \u201cJAGURS,\u201d and an earthquake-cycle program, \u201cRSGDX.\u201d Our optimization strategy for collective communication is to split the Message Passing Interface (MPI) communicator and perform multistage localized communication to minimize the communication frequency, transferred data size, and network congestion. Moreover, in the case of severe load imbalances, we apply cyclic distribution and extend the axes for parallelization. For each application, we conduct a performance evaluation with massively parallel execution on the K computer. It is shown that our optimized code enables JAGURS to attain a 21.8\u00d7 speedup for collective communication and a 7.9\u00d7 speedup for the time-step loop on 8748 nodes (69,984 cores). RSGDX attains a 4.25\u00d7 speedup for collective communication and an 18.7\u00d7 speedup for the time-step loop on 8192 nodes (65,536 cores).<\/jats:p>","DOI":"10.1177\/1094342016636670","type":"journal-article","created":{"date-parts":[[2016,3,15]],"date-time":"2016-03-15T20:29:26Z","timestamp":1458073766000},"page":"454-468","update-policy":"https:\/\/doi.org\/10.1177\/sage-journals-update-policy","source":"Crossref","is-referenced-by-count":2,"title":["Parallel-algorithm extension for tsunami and earthquake-cycle simulators for massively parallel execution on the K computer"],"prefix":"10.1177","volume":"30","author":[{"given":"Kazuto","family":"Ando","sequence":"first","affiliation":[{"name":"Center for Earth Information Science and Technology, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mamoru","family":"Hyodo","sequence":"additional","affiliation":[{"name":"Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Toshitaka","family":"Baba","sequence":"additional","affiliation":[{"name":"Institute of Technology and Science, University of Tokushima, Tokushima, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takane","family":"Hori","sequence":"additional","affiliation":[{"name":"Research and Development Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Toshihiro","family":"Kato","sequence":"additional","affiliation":[{"name":"1st Government and Public Solution Division, NEC Corporation, Tokyo, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Masaru","family":"Watanabe","sequence":"additional","affiliation":[{"name":"HPC Application Solutions Division, Technical Computing Solutions Unit, Fujitsu Ltd, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shin-ichi","family":"Ichikawa","sequence":"additional","affiliation":[{"name":"HPC Application Solutions Division, Technical Computing Solutions Unit, Fujitsu Ltd, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hisakuni","family":"Kitahara","sequence":"additional","affiliation":[{"name":"Integration Business Division, Fujitsu Social Science Laboratory Ltd, Kawasaki, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hitoshi","family":"Uehara","sequence":"additional","affiliation":[{"name":"Center for Earth Information Science and Technology, Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hikaru","family":"Inoue","sequence":"additional","affiliation":[{"name":"HPC Application Solutions Division, Technical Computing Solutions Unit, Fujitsu Ltd, Chiba, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"179","published-online":{"date-parts":[[2016,7,27]]},"reference":[{"key":"bibr1-1094342016636670","doi-asserted-by":"publisher","DOI":"10.1007\/s00450-012-0211-7"},{"key":"bibr2-1094342016636670","doi-asserted-by":"publisher","DOI":"10.1109\/MC.2009.370"},{"key":"bibr3-1094342016636670","doi-asserted-by":"publisher","DOI":"10.1007\/978-94-007-7269-4_3"},{"key":"bibr4-1094342016636670","doi-asserted-by":"publisher","DOI":"10.1177\/1094342015584090"},{"key":"bibr5-1094342016636670","doi-asserted-by":"publisher","DOI":"10.1007\/s00024-015-1049-2"},{"key":"bibr6-1094342016636670","volume-title":"Hierarchical matrices. 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