From na-net@na-net.stanford.edu Sun Jun 18 16:38:09 1989 Received: from beauty.stanford.edu by antares.mcs.anl.gov (4.0/SMI-DDN) id AA19574; Sun, 18 Jun 89 16:37:47 CDT Received: from patience.stanford.edu by beauty.stanford.edu (4.0/inc-1.5) id AA07757; Sun, 18 Jun 89 14:07:55 PDT Received: from bravery.stanford.edu by patience.stanford.edu (4.0/inc-1.5) id AA11947; Sun, 18 Jun 89 13:58:49 PDT Received: by bravery.stanford.edu (4.0/inc-1.5) id AA04170; Sun, 18 Jun 89 14:11:19 PDT Date: Sun, 18 Jun 89 14:11:19 PDT From: na-net@na-net.stanford.edu Message-Id: <8906182111.AA04170@bravery.stanford.edu> Return-Path: Subject: NA-NET distribution message Errors-To: nanet@na-net.stanford.edu Maint-Path: maintainer@na-net.stanford.edu To: na-net@na-net.stanford.edu Reply-To: na-net@na-net.stanford.edu Comment: requests, comments or problems to nanet@na-net.stanford.edu Comment: submissions to na@na-net.stanford.edu Comment: alternate address: na%na-net@score.stanford.edu Status: RO NA Digest Sunday, June 18, 1989 Volume 89 : Issue 24 Today's Editor: Cleve Moler Today's Topics: NA News Policy on Long Conference Announcements Solution of Linear Congruence Equations Stability for Initial-Boundary Value Problems Scientific Computing/Computational Math/Numerical Science Linpack-like routines in C Continued Support for PRC Students/Researchers on NSF ------------------------------------------------------- From: Eric Grosse (and Cleve Moler) Date: Mon, 12 Jun 89 21:05:46 EDT Subject: NA News Policy on Long Conference Announcements As was suggested in last week's Digest, let's put long conference announcements in NETLIB. Since we're archiving the NA-Digest to the dawn of time, the switch won't even increase disk use. :-) Authors should choose a 14-character or less alphanumeric conference title, say NAConFab89, and include the hint mail netlib@research.att.com send NAConFab89 from meetings in their brief announcement in the NA-Digest. They should mail the long form to ehg@research.att.com with Subject: deposit meetings/NAConFab89 If the name collides with an existing file, the new announcement will be appended to the existing one. Best wishes Eric ------------------------------ From: Giuseppe Paruolo Date: Mon, 12 Jun 89 11:47:08 ITA Subject: Solution of Linear Congruence Equations Given the linear congruence equation a x = b mod m (*) we know that (*) does have solution if and only if gcd(a,m) divides b. In this situation: 1) is it possible to solve (*) analitically? (I think the answer is no, but I'd like confirmation anyway) If the answer to 1) is no as I suppose: 2) what are the existing algorithms to solve this problem? which of them is the most efficient? 3) what are the concrete problems, the real applications in which equations like (*) have to be solved, and where their solution affects heavily the computational complexity and/or the storage requirement? Bibliographical references on this problem and suggestions are welcome. Thank you in advance. Giuseppe Paruolo address: Giuseppe Paruolo - CINECA - via Magnanelli 6/3 40033 Casalecchio - Bologna - Italy e-mail: agg0@icineca.bitnet or na.paruolo@na-net.stanford.edu fax: + 39 51 598 472 ------------------------------ From: Rakesh Date: Mon, 12 Jun 89 10:14:44 EDT Subject: Stability for Initial-Boundary Value Problems I am looking for articles which have reasonable sufficient conditions for the stability of difference schemes, for initial_boundary value problems for the wave equation in 2 space dimensions i.e. u - u - u + q(x,y)u = F(x,y,t) x>0, y in R , t>0 tt xx yy IC u(x,y,0) = 0, u (x,y,0) = 0 t BC u(0,y,t) = f(y,t) { or u (0,y,t) = f(y,t) } x I am aware of the work on first order systems, but when I convert the above equation to a first order system it fails to satisfy the "non-characteristic" condition needed for the results for systems. Perhaps, I am overlooking something. I would appreciate any help on this matter. Thanks. rakesh@vax1.acs.udel.edu (on arpanet) (302) 451 2910 ------------------------------ From: Benedict Leimkuhler Date: 15 Jun 89 09:05:54 GMT Subject: Scientific Computing/Computational Math/Numerical Science I am interested in what the opinions of others are on the meanings of the terms "Scientific Computing," "Computational Mathematics," and "Numerical Science." Recently, these terms have become buzzwords in position announcements and popular science articles. For example, Stanford has recently created a "Program in Computational Mathematics and Scientific Computing." In an article in the latest issue of The Economist which focused on large scale simulation of physical phenomena on supercomputers, the above three terms are stated to be synonyms. I expect to see a large number of new positions created in the next few years with one of those terms in the title, and I'm rather curious about whether or not I'm in one of these fields. To add to the confusion, Bill Gear, in his farewell address as SIAM president, discusses the importance in the coming years of something called "Computing Science." I have always sort of considered myself to be a "Numerical Analyst." Now I know that the people who run supercomputer centers use some terms like "Supercomputing" or "Supercomputing Science," and if they work on graphical output from supercomputers they call it "Visualization Science." The parallel processing community has nothing against the term "Parallel Computing," as far as I know, since they and everyone else seems to use the term in titles and abstracts all the time. If you have any ideas or more terms to throw into this alphabet soup send me EMAIL and I will post a summary to the net. Ben Leimkuhler (Numerical Analyst?) Helsinki University of Technology, Finland ------------------------------ From: Daniel Q. Naiman Date: 16 Jun 89 06:55:14 GMT Subject: Linpack-like routines in C Does anyone out there know of alternatives to Linpack written in the C language and for which the source code is in the public domain. It is important that it have various matrix inversion programs, especially for banded matrices. Also, it is important that the programs be written with numerical issues taken seriously. Please post or send mail to Dan Naiman (msc_wdqn.jhunix) The Johns Hopkins University - HCF ------------------------------ From: National Science Foundation Date: Thu, 15 Jun 89 17:36:11 -0400 Subject: Continued Support for PRC Students/Researchers on NSF The following letter was signed today by Erich Bloch, Director, NSF, to announce the availability of supplementary funds to continue support for those students and researchers from the People's Republic of China whose tenure in the United States will be altered. As with other supplement requests, these should be sent to the NSF Program Officer who was designated as the cognizant program official when the research award was made. Dear Colleague: Last week, in response to events in the People's Republic of China (PRC), President Bush offered a one-year delayed departure to all PRC students, scholars and other visitors now in the United States. Many visitors from the PRC currently receive support through NSF awards, particularly as graduate students and postdoctoral researchers. Effective immediately, NSF will entertain requests for supplements if the duration of the stay of a PRC student or other researcher supported on an existing award is altered as the result of the President's initiative. Requests for supplements under this provision should be in the form of a brief letter, signed by both the principal investigator and the institutional official, and submitted directly to the appropriate NSF Program Official. The letter should state clearly that this is a supplemental request to provide continued support for a PRC student or researcher. The individual(s) involved should be identified and the circumstances of the case outlined in sufficient detail for the NSF Program Manager to evaluate the request. NSF staff will make every attempt to expedite the processing of these requests and provide notification of award to the institutions promptly. Erich Bloch Director ------------------------------ End of NA Digest ************************** -------