{"id":2927,"date":"2021-11-16T15:36:45","date_gmt":"2021-11-16T21:36:45","guid":{"rendered":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/?post_type=tribe_events&#038;p=2927"},"modified":"2022-02-11T11:19:52","modified_gmt":"2022-02-11T17:19:52","slug":"lans-seminar-21","status":"publish","type":"tribe_events","link":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/event\/lans-seminar-21\/","title":{"rendered":"LANS Seminar"},"content":{"rendered":"<p><strong>Seminar Title<\/strong>: GPMR: An Iterative Method for Square Partitioned Linear Systems<br \/>\n<strong>Speaker<\/strong>: Alexis Montoison<br \/>\n<strong>Title<\/strong>: PhD Student<br \/>\n<strong>Affiliation<\/strong>: Polytechnique Montreal<\/p>\n<p><strong>Date\/Time<\/strong>: February 16, 2022 \/ 10:30 AM &#8211; 11:30 AM<br \/>\n<strong>Location<\/strong>: See meeting URL on the cels-seminars website\u00a0(requires Argonne login)<\/p>\n<p><strong>Host<\/strong>: Francois Pacaud<\/p>\n<hr \/>\n<p><strong>Description<\/strong>: We present a new iterative method named GPMR (General Partitioned Minimal Residual) for square 2&#215;2 block linear systems. GPMR is based on a new process that simultaneously reduces two rectangular matrices to upper Hessenberg form and is closely related to the block-Arnoldi process. We compare the performance of GPMR with GMRES on linear systems from the SuiteSparse Matrix Collection. In our experiments, GPMR terminates significantly earlier than GMRES on a residual-based stopping condition with an improvement ranging from around 10% up to 50% in terms of number of iterations.<\/p>\n<p>GPMR is implemented in Julia, as part of our Krylov.jl collection of Krylov methods. Krylov.jl provides Julia implementations of a growing number of the most useful Krylov method for linear systems, least-squares, and least-norm problems, together with facilities for saddle-point systems. We illustrate\u00a0 the main features of Krylov.jl on our implementation of GPMR.<\/p>\n<p><em>Please note that the meeting URL for this event can be seen on the <\/em>cels-seminars website<em>, which requires an Argonne login.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Seminar Title: GPMR: An Iterative Method for Square Partitioned Linear Systems Speaker: Alexis Montoison Title: PhD Student Affiliation: Polytechnique Montreal Date\/Time: February 16, 2022 \/ 10:30 AM &#8211; 11:30 AM Location: See meeting URL on the cels-seminars website\u00a0(requires Argonne login) &hellip; <a href=\"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/event\/lans-seminar-21\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":43,"featured_media":0,"template":"","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"_tribe_events_status":"","_tribe_events_status_reason":"","footnotes":"","_members_access_role":[],"_members_access_error":""},"tags":[],"tribe_events_cat":[2],"class_list":["post-2927","tribe_events","type-tribe_events","status-publish","hentry","tribe_events_cat-seminar","cat_seminar"],"acf":[],"_links":{"self":[{"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tribe_events\/2927","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tribe_events"}],"about":[{"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/types\/tribe_events"}],"author":[{"embeddable":true,"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/users\/43"}],"version-history":[{"count":3,"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tribe_events\/2927\/revisions"}],"predecessor-version":[{"id":2966,"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tribe_events\/2927\/revisions\/2966"}],"wp:attachment":[{"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/media?parent=2927"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tags?post=2927"},{"taxonomy":"tribe_events_cat","embeddable":true,"href":"https:\/\/wordpress.cels.anl.gov\/lans-seminars\/wp-json\/wp\/v2\/tribe_events_cat?post=2927"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}