From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=BAYES_00,DATE_IN_PAST_12_24, FORGED_HOTMAIL_RCVD2,FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,ab436e97ff76821f X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII Received: by 10.204.151.213 with SMTP id d21mr3303930bkw.0.1342043330831; Wed, 11 Jul 2012 14:48:50 -0700 (PDT) Path: m12ni34bkm.0!nntp.google.com!news2.google.com!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail From: gautier_niouzes@hotmail.com Newsgroups: comp.lang.ada Subject: Re: Does Ada need elemental functions to make it suitable for scientific work? Date: Wed, 11 Jul 2012 01:41:50 -0700 (PDT) Organization: http://groups.google.com Message-ID: References: NNTP-Posting-Host: 206.122.158.4 Mime-Version: 1.0 X-Trace: posting.google.com 1341996111 10287 127.0.0.1 (11 Jul 2012 08:41:51 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Wed, 11 Jul 2012 08:41:51 +0000 (UTC) Cc: nma@12000.org In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=206.122.158.4; posting-account=gRqrnQkAAAAC_02ynnhqGk1VRQlve6ZG User-Agent: G2/1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Date: 2012-07-11T01:41:50-07:00 List-Id: Ada novice=A0: > In finite element formulations, one will usually end up with sparse matri= ces. I do not know whether Ada has support for such matrices. Matlab for in= stance has dedicated solver(s) for the system Ax=3Db when A is a sparse mat= rix. I think beside storage consideration, sparse matrices solvers are fast= er (I can be wrong though). They are fast but it all depends on the problem and the conditioning of the= matrix. Sometimes you are also well served by band matrices and a good alg= orithm to rearrange the node numbering so that nodes that are close in the = mesh end up with close indices and then the matrix has fewer non-zero diago= nal bands around the main diagonal. Choice of solvers for sparse matrices are limited - because they need to. e= .g. a LU decomposition would require to know where are the non-zeros for ha= ving L and U stored as sparse matrices. And probably they are not sparse at= all... You find a sparse matrix package and appropriate solvers in Mathpaqs pack t= here: http://sf.net/projects/mathpaqs/ ___________________________________________________________________________= ___ Gautier's Ada programming -- http://gautiersblog.blogspot.com/search/label/= Ada=20 NB: follow the above link for a valid e-mail address