From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 54ce2237 for ; Wed, 18 Sep 2019 04:52:45 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id BA1449B9C5; Wed, 18 Sep 2019 14:52:43 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id E50EF947C8; Wed, 18 Sep 2019 14:52:27 +1000 (AEST) Received: by minnie.tuhs.org (Postfix, from userid 112) id D6AD9947C8; Wed, 18 Sep 2019 14:52:25 +1000 (AEST) Received: from darkstar.fourwinds.com (fourwinds.com [63.64.179.162]) by minnie.tuhs.org (Postfix) with ESMTPS id 6328394797 for ; Wed, 18 Sep 2019 14:52:25 +1000 (AEST) Received: from darkstar.fourwinds.com (localhost [127.0.0.1]) by darkstar.fourwinds.com (8.15.2/8.15.2) with ESMTP id x8I4qOdR002495 for ; Tue, 17 Sep 2019 21:52:24 -0700 Received: from darkstar.fourwinds.com (jon@localhost) by darkstar.fourwinds.com (8.15.2/8.15.2/Submit) with ESMTP id x8I4qOiO002491 for ; Tue, 17 Sep 2019 21:52:24 -0700 Message-Id: <201909180452.x8I4qOiO002491@darkstar.fourwinds.com> From: Jon Steinhart To: tuhs@tuhs.org In-reply-to: <2af4396e3f1133dfb93c2a92722e6f0e850ade55@webmail.yaccman.com> References: <2af4396e3f1133dfb93c2a92722e6f0e850ade55@webmail.yaccman.com> Comments: In-reply-to "Steve Johnson" message dated "Tue, 17 Sep 2019 21:47:47 -0700." MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-ID: <2489.1568782344.1@darkstar.fourwinds.com> Content-Transfer-Encoding: 8bit Date: Tue, 17 Sep 2019 21:52:24 -0700 X-JON-SPAM: local delivery Subject: Re: [TUHS] block operations in editors, was My EuroBSDcon talk X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" Steve Johnson writes: > This is one of my pet peeves.  "Random Access" memory is far from random when > you look at the time it takes to do the accesses.  With modern memories, > accessing a column can be 20 to 40x slower than accessing a row.  This is > particularly irritating when doing AI training, where training reuses 4-d > tensors transposed, a very painful operation. > > In FORTRAN days, I once used a vector package in which you described a vector > by giving the first element, the second element, and a count.  So you could > describe rows, columns, a matrix diagonal, and even rows and columns from back > to front.  Fortran passed arguments by address, which made the whole thing easy > and fast. > > Steve Remember the words of that great performance pioneer Jimmy Durante: ras-a-ma-cas.