From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp1 ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id WdaJE9bKU2DeEwAA0tVLHw (envelope-from ) for ; Thu, 18 Mar 2021 21:49:10 +0000 Received: from aspmx1.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp1 with LMTPS id 8AzHDtbKU2DxawAAbx9fmQ (envelope-from ) for ; Thu, 18 Mar 2021 21:49:10 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id EC21D21BD8 for ; Thu, 18 Mar 2021 22:49:09 +0100 (CET) Received: from localhost ([::1]:50278 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lN0Vw-00032G-OK for larch@yhetil.org; Thu, 18 Mar 2021 17:49:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40158) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lN0Vq-00032A-O4 for guix-patches@gnu.org; Thu, 18 Mar 2021 17:49:02 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:36692) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lN0Vq-0006Y2-Gj for guix-patches@gnu.org; Thu, 18 Mar 2021 17:49:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lN0Vq-0002LO-FK for guix-patches@gnu.org; Thu, 18 Mar 2021 17:49:02 -0400 X-Loop: help-debbugs@gnu.org Subject: [bug#47237] [PATCH] gnu: metis: Use 64-bit floating pointer numbers on 64-bit architectures. 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spf=pass (aspmx1.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Migadu-Spam-Score: -1.31 Authentication-Results: aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=gmail.com header.s=20161025 header.b=DsS88tns; dmarc=fail reason="SPF not aligned (relaxed)" header.from=gmail.com (policy=none); spf=pass (aspmx1.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Migadu-Queue-Id: EC21D21BD8 X-Spam-Score: -1.31 X-Migadu-Scanner: scn0.migadu.com X-TUID: lMd6smlIVa6H Hi, On Thu, 18 Mar 2021 at 16:27, Emmanuel Agullo wrote: > In numerical linear algebra in particular and hpc in > general, the trend is more and more to use reduced > floating point arithmetic whenever possible (for memory > footprint, communication volume and possibly computational > time). I have no experience with using floating point > numbers in partitioners such as metis. But I strongly [...] > choice. Something like mypackage_i32_r64 (if there > is a general convention (beyond guix) to follow, > even better). [It may even be great to use two versions > of the same package to facilitate mixed arithmetic, > but we can certainly pospone that discussion as it > would certainly open two many issues for now]. I am probably out-of-scope, and it does probably not make sense for partitioners as Metis, how are considered mixed precision solvers? i.e., computing some part using 64 bits floating points and other part using 32 bits. (My memory is not clear but I remember reading couple of weeks ago an acceleration with 3 levels of float-pointing precision.) In the i32_r64 example of convention, what should be considered as rXY? The final accuracy, whatever the internals? Are these mixed precision solvers used and in the trend? Well, I do not know if these questions make sense. Cheers, simon